Upload
others
View
12
Download
0
Embed Size (px)
Citation preview
IHU,.IR-3273
TECHNICAL REPORT BRL-TR-3273
BRLPENETRATION OF SHAI’ED-CHARGE JETSINTO GLASS ANI) CRYS7’ALLINE QUARTZ
G. [;. IIA(JV1;l<P. 11. Nli’1’f II;l<}v(x)[)
R. F. EIENCKA. MEI.ANI
U.S. ARMY LABOI<A’I’OR}” COMMAND
BALLISTIC RESEARCH LABORATORY
ABERDEEN PROVING GROUND, MARYLAND
BRL·TR·3273
• •
ntE copy
TECHNICAL REPORT BRL-TR-3273
PENETRATION OF SHAPED-CHARGE JETS INTO GLASS AND CRYSTALLINE QUARTZ
G. E. IIAUVER P. II. NETIIERWOOD
R. F. BENCK A. I\lELA['\!
S E PTEivlB E R j()l) 1
APPROVED FOR PUBLIC RI'LI'i\SF; DISTRIIll' no" IS U:'-:UMITI'D.
U.S. ARMY LABORATORY COMMAND
BALLISTIC RESEARCH LABORATORY
ABERDEEN PROVING GROUND, MARYLAND
NOTICES
Destroy this report when it is no Iongcr needed. DO NOT return it to the originator.
Additional copies of tt]is report may be obtained from the Nation:]l Technical Informa!lon S(?rvlcc,
U.S. Department of Commcrc[; , 5285 Port RoyGl Road, Springfield, VA 22161
The findings of this report are not to k construed ,X an of fic]al Department of tile Army posltlon,
unless so design atccj by other authorized documents
The use of trade names or mar~ufacturcrs’ names Ir) tt]is r[eport does not consti[~lte lmdorse[]lcf)t
of any commercial product.
NOTICES
Destroy this report wrlen it is no longer needed. DO NOT return it to the origin3tor.
Additional copies of this report rn3y be obt3ined frorn the N3tional TechniC(l1 Information S(;rvlcc. U.S. Dep3rtrnent of Cornrnerce, 5285 Port Royal Road, Sprirlgfield, VA 22161
The findings of this report are not to be construed 3S 3n officl;]1 Ocp3rtrnent of ttle Arrny position, unless so design3tcci by otrwr 3uthorized documents
The use of tr3de names or m3flufacturers' n3fTlCS in trlis report does not corlstltllte Ifldorseflleflt of any cornrnerci31 product.
REPORT DOCUMENTATION PAGEform Approval
(IMB No i2/OJ 0188
Penetration of Shaped-Charge Jets Into Glass and Crystalline Quartz
6. AUTHOR(S)
G. E. Hauver, P. H. Netherwood, R. F. Benck, and A. Melani
7. PERFORMING ORGANIZATION NAME(S) AND AOORESS(E5)
DirectorU.S. Army Ballistic Research LaboratoryATTN: SLCBR-TB-AMAberdeen Proving Ground, MD 21005-5066
1L161102AH43
8. PERFORMING ORGANIZATIONREPORT NUMBER
19. SPONSORING MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSORING MONITORING
AGENCY REPORT NUMBER
U.S. Army Ballistic Research LaboratoryATTN: SLCBR-DD-TAberdeen Proving Ground, MD 21005-5066
BRL-TR-327 3
12a. DISTRIBUTION AVAILABILITY STATEMENT 12b. DISTRIBUTION CODE
Approved for public release; distribution is unlimited.
I13. ABSTRACT (Max/mum 200 words)
Penetration of shaped charge jets into glass and crystalline quartz was studied by high-speed photographyand flash radiography to identify behavior responsible for the effectiveness of glass against shaped chargethreats. The behavior of crystalline quartz was relatively conventional. The greater effectiveness of silica andhigh-silica glasses was clearly indicated by an abrupt decrease in penetration velocity shortly after impact.High-speed photographs showed that the penetration path opened to its maximum diameter within a fewmicroseconds and then rapidly closed after the penetration front passed. The penetration velocity decreasedwhen jet elements, disturbed by cavity closure, arrived at the penetration front. The penetration path inrecovered targets was filled with a red copper-glass that resulted from an extended interaction between jet andtarget materials, Closure preceded brittle failure in the surrounding glass target, and it was concluded thatprimary closure is caused by recovery from high pressures near the penetration front.
14. SUBJECT TERMS 15 NUMBER OF PAGES
59penetration; jets; shaped-charge jets; glass; quartz; cavity closure 16 PRICE COOE
17. SECURITY CLASSIFICATION 18 SECURITY CLASSIFICATION 19 SF CURITY CLASSIFICATION 20 LIMITATION OF ABSTRAC1OF REPORT OF THIS PAGE OF ABSTRACT
UNCLASSIFIED UNCLASSIFIED UNCLASSIFIED SARUSPJ754001 :80 5’)01)
UNCLASSIFIED\+c+flcjdrdirr~.’98RWJ?H9j,,, (1,-! :, .,.J! !11 * I h!I! ‘w’,
IINr.1 A~~IFIED DOCUMENTATION PAGE
form Approv('d REPORT OMB No 01040188
PiJOJI' rl'p ,rl I' ; t'l. r ~, '1 ~ ,r :' 1 " It' ' 'C' t ., 'CC,' " ,,1 l""1j"-':' , " ""
, , c J',' ; P!' 1'-',," r 'I', >',', '11 ,r",:' J' :1, '1', ", p, "". I ,-. ',1"1 I : Il,! , ",r ",
l IT r~'( r 1 1 'i ~ 1 \ r • I r I , 1 11 1 I I ". "~" j I, j 11-.,,'111'; Ii" ",', , ,
" " "-I,i ., .... ,,''1 r., I " I \, :11 I rr, ~ :)I,r,jl'rl I" I' rT ar, II" p'!'[ j"~)" t ,t """ \ Iit'd' .'1 • ,.t, 11'- \T\ ,11)\ .'\ J "",1" r"j,,'I"l')
" '" , ,'. l',I' • , ~ l' l ". ·'1 " ',r·',· ",1" (,' r't '1'l'1 tl', '1' I ,[",pr dl ,I" jl d H"r,' r~ ,''J,.jt''I\,'rl
I I"" I ~ I j 1'1' " t I ,j I'" ., .: ",Ir ll' II .. '.' ,\,' , 'ii,' 1 j 1 !'o> ." t -,11 1,"" . , ' I :jl I' 'r "'I .', " I~' 'I j I, t I' " f " i'" • ; IJ 'i 1,1 11' ,>4,M J '/\' 1', l' r lit r' 1\ .')',1,)1
1. AGENCY USE ONL Y (l t'JVt' hlank) -,2 REPORT DATE 13. REPORT TYPE AND DATES COVERED
September 19lJ 1 Final, January 1984-January 1989
4, TITLE AND SUBTITLE 5. FUNDING NUMBERS
Penetration of Shaped-Charge Jets Into Glass and Crystalline Quartz
6, AUTHOR(S) 1L161102AH43
G. E. Hauver, P. H. Netherwood, R F. Benck, and A. Melani
7, PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PE RFORMING ORGANIZA TION
Director REPORT NUMBER
U,S. Army Ballistic Research Laboratory AnN: SLCBR-TB-AM Aberdeen Proving Ground, MD 21005-5066
9. SPONSORING MONITORING AGENCY NAME(S) AND ADDRESS(ES) 1O, SPONSORING i MONITORING AGENCY REPORT NUMBER
U,S. Army Ballistic Research Laboratory BRL-TR-327 3
AnN: SLCBR-DD-T Aberdeen Proving Ground, MD 21005-5066
11. SUPPLEMENTARY NOTES
12a. DISTRIBUTION AVAILABILITY STAHMENT 12b. DISTRIBUTION CODE
Approved for public release; distribution is unlimited,
13, ABSTRACT (MaXImum 200 words)
Penetration of shaped charge jets into glass and crystalline quartz was studied by high-speed photography and flash radiography to identify behavior responsible for the effectiveness of glass against shaped charge threats. The behavior of crystalline quartz was relatively conventional. The greater effectiveness of silica and high-silica glasses was clearly indicated by an abrupt decrease in penetration velocity shortly after impact. High-speed photographs showed that the penetration path opened to its maximum diameter within a few microseconds and then rapidly closed after the penetration front passed, The penetration velocity decreased when jet elements, disturbed by cavity closure, arrived at the penetration front. The penetration path in recovered targets was filled with a red copper-glass that resulted from an extended interaction between jet and target materials. Closure preceded brittle failure in the surrounding glass target, and it was concluded that primary closure is caused by recovery from high pressures near the penetration front.
14, SUBJECT TERMS 15 NUMBER OF PAGES
59 penetration; jets; shaped-charge jets; glass; quartz; cavity closure 16. PRICE CODE
17, SECURITY ClASSIFICATION 18. SECURITY CLASSIFICA TlON 19 Sf CURITY ClASSIFICA TION 20. LIMITATION OF J\BSTRACT OF REPORT OF THIS PAGE OF ABSTRACT
UNCLASSIFIED UNCLASSI FI ED UNCLASSIFIED SAR , ,
UNCLASSIFIED \ '\. ' ,) :' ~ • \ t l " , 1 1 -\' ~ '"I
• 1K 'IJ.1
il
INTfcNflONALLY II r r 131ANK
II
TABLE OF CONTENTS
Ei3Q
LIST OF FIGURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ACKNOWLEDGMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2. EXPERIMENTS AND DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.1
2.2
2.3
2.4
2.4.1
2.4.2
2.4.3
2.5
2.6
2.7
2.8
Test Charge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Examination of Penetration-Time Data . . . . . . . . . . . . . . . . . . . . . . . . . . .
Flash-Radiographic Observations During Jet Penetration . . . . . . , . . . . . .
Photographic Measurementsof Penetration-Time . . . . . . . . . . . . . . .
Experimental Configurations for Photographic Studies . . . . . . . . .
Jet Penetration Into Fused Quartz . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Jet Penetration Into Soda-Lime Glass . . . . . . . . . . . . . . . . . . . . . . . . . .
Examination of Recovered Glass Targets . . . . . . . . . . . . . . . . . .
Formation and Role of Red Glass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Test for Permanent Densification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Examination of Recovered Crystalline Quartz Targets . . . . . . . . . . . . . . . .
3. SUMMARY AND FINAL DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4. REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DISTRIBUTION LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
vii
1
2
2
3
3
8
911
16
3242
44
46
46
51
53
Ill
TABLE OF CONTENTS
LIST OF FIGURES ........................................... v
ACKNOWLEDGMENTS .............. . . . . . . . . . . . . . . . . . . . . . . . . . . vii
1. INTRODUCTION ............................................ .
2.
2.1 2.2 2.3 2.4 2.4.1 2.4.2 2.4.3 2.5 2.6 2.7 2.8
3.
4.
EXPERIMENTS AND DISCUSSION .............................. .
Test Charge ............................................. . Examination of Penetration-Time Data .......................... . Flash-Radiographic Observations During Jet Penetration ............. . Photographic Measurements of Penetration-Time .................. .
Experimental Configurations for Photographic Studies ............. . Jet Penetration Into Fused Quartz ........................... . Jet Penetration Into Soda-Lime Glass ......................... .
Examination of Recovered Glass Targets ........................ . Formation and Role of Red Glass .............................. . Test for Permanent Densification .............................. . Examination of Recovered Crystalline Quartz Targets ............... .
SUMMARY AND FINAL DISCUSSION ............................ .
REFERENCES ............................................. .
2
2 3 3 8 9
11 16 32 42 44 46
46
51
DISTRIBUTION LIST ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
iii
Iv
INTE N IIONAl lY l Ff T RLANK.
IV
LIST OF FIGURES
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
Photograph of a Glass Target During Penetration by a Shaped Charge Jet . .
Target Configurations for Radiographic Tests . . . . . . . . . . . . . . . .
Flash Radiographs Showing Jet Penetration Into (A) Fused Quartz and(B) Crystalline Quartz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Profiles of Optical Density Across Penetration Paths in (A) Fused Quartz and(B) Crystalline Quartz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Configuration for Photographic Tests With Back Lighting . . . . . . . . . . . . . . . .
Configuration for Photographic Tests With Front Lighting . . . . . . . . . . . . . . . .
Penetration-Time Data for the Initial Part of Jet Penetration Into FusedQuartz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Combined Radiographic and Photographic Data for Jet Penetration IntoFused Quartz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Comparison of Penetration-Time Data for Jet Penetration Into Fused Quartz(FQ)and Crystalline Quartz (CQ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Photographs of a Soda-Lime Glass Target During Penetration by aContinuous Jet (Test I ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Penetration-Time Data for the Jet Penetration Shown in Figure 10 . . . . . . . . .
Photographs of a Soda-Lime Glass Target During Penetration by aContinuous Jet(Test 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Penetration-Time Data for the Jet Penetration Shown in Figure 12 . . . . . . . . .
Path Diameter as a Function of Time (Continuous Jets) . . . . . . . . . . . . . .
Penetration-Time Curves From Figure 13, Including a Path for the JetElement That Arrives at the Transition Point . . . . . . . . . . . . . . . . . . . . .
Photographs of a Soda-Lime Glass Target During Penetration by aParticulated Jet(Test l) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Path Diameter as a Function of Time (Particulate Jet) . . . . . . . . . . . . . . . . .
Penetration-Time Data for the Jet Penetration Shown in Figure 16 . . . . . . . .
v
!2.!?Q
2
4
5
7
9
10
12
13
15
17
18
20
21
22
23
24
26
27
LIST OF FIGURES
Figure
1 . Photograph of a Glass Target During Penetration by a Shaped Charge Jet 2
2. Target Configurations for Radiographic Tests ........................ . 4
3. Flash Radiographs Showing Jet Penetration Into (A) Fused Quartz and (B) Crystalline Quartz ....................................... . 5
4. Profiles of Optical Density Across Penetration Paths in (A) Fused Quartz and (B) Crystalline Quartz ....................................... . 7
5. Configuration for Photographic Tests With Back Lighting 9
6. Configuration for Photographic Tests With Front Lighting 10
7. Penetration-Time Data for the Initial Part of Jet Penetration Into Fused Quartz ................................................. . 12
8. Combined Radiographic and Photographic Data for Jet Penetration Into Fused Quartz ............................................ . 13
9. Comparison of Penetration-Time Data for Jet Penetration Into Fused Quartz (FQ) and Crystalline Quartz (CQ) .............................. . 15
10. Photographs of a Soda-Lime Glass Target During Penetration by a Continuous Jet (Test 1) ..................................... . 17
11. Penetration-Time Data for the Jet Penetration Shown in Figure 10 ........ . 18
12. Photographs of a Soda-Lime Glass Target During Penetration by a Continuous Jet (Test 2) ..................................... . 20
13. Penetration-Time Data for the Jet Penetration Shown in Figure 12 ........ . 21
14. Path Diameter as a Function of Time (Continuous Jets) ................ . 22
15. Penetration-Time Curves From Figure 13, Including a Path for the Jet Element That Arrives at the Transition Point ...................... . 23
16. Photographs of a Soda-Lime Glass Target During Penetration by a Particulated Jet (Test 1) ..................................... . 24
17. Path Diameter as a Function of Time (Particulated Jet) ................ . 26
18. Penetration-Time Data for the Jet Penetration Shown in Figure 16 27
v
1!3. Photographs of a Soda Lime Glass Target During Penetration by a
Particulated Jet(Test 2) ..,..... . 28
29Penetration Time Data for the Jet Penetration Shown in Figure 1920.
21. Back-Lighted Photographs of a Soda-Lime Glass Target During Penetration
bya Particulated Jet(Test 3)... . 30
3122.
23.
Penetration Time Data for the Jet Penetration Shown in Figure 21
Photograpt~s of a Monolithic Soda-Lime Glass Target During Penetration by
aParticulated Jet(Test 4).... . 33
34Penetration Time Data for the Jet Penetration Shown in Figure 2324.
25. Fused Quartz Target Sectioned to Expose the Penetration Path Filled With
Rcd Glass..,..,.. .
26. (A) Static R:dograpt) of the Penetration Path in Fused Quartz: (B) SEM
Micrograph of Fled Glass From the Pen[:tration Path Irl Fused Quartz
27. Red Glass That Flowed From tile Back of a Perforated Fused Quartz
Target . . 38
28. Recovcrcd [argot of Boroslhcate Glass St~owlng Red Glass Displaced When
the Slug l:ntercd the Target . . . . .
Glass Targe:s Penetrated by (A) a Copper Jet, (B) a Steel Jet, and (C) In
Aluminum Jet. (D) is a Deposit of Material Ejected Frorr] tllc Pc[lutratlon
Path ln (C.. .
29.
40
41
43
Tapered Jet Particles In Red Glass30.
31.
32.
Data of Meade and Jeanloz
Target Cor]figuration Used to Recover Per[lla[lc[)tly Denslfied Fused
Quartz .
(A) Static Radiograph] of tt]e Crystalline Quartz Target; (B D) Arc Cross
Suctions of the Target III (A) Showing Cavity Closurt:
33.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33
Photographs of a Soda Lime Glass Target During Penetration by a Particulated Jet (Test 2)
Penetration Tirne Data for the Jet Penetration Shown in Figure 19
Backlighted Photographs of a Soda-Lirne Glass Target During Penetration by a Particulated Jet (Test 3) ...
Penetration Time Data for the Jet Penetration Shown in Figure 21
Photographs of a Monolithic Soda·Lirne Glass Target During Pelletr<ltion by a Particulated Jet (Test 4)
Penetration Tirne Data for the Jet Penetration Shown in Figure 23
Fused Quartz Target Sectioned to Expose trw Penetration Path Filled With Red Glass ..
(A) Static Rddiograpl1 of the Penetration Path in Fused Quartz: (B) St=M Micrograph of Red Glass Frorn the Penetration Path in Fused Quartz
Red Glass That Flowed Frorn the Back of a Perforated Fused Quartz Target
Recovered r arget of Borosilicate Glass SI10wing Rud Glass Displacud Wlwn the Slug E:ntered the Target
Glass Targe:s Penetrated by (A) a Copper Jet. (B) a Steel Jet. and (C) ,111
AlurninulT1 Jet. (D) is a Deposit of Material Ejected From tlw Pelwtratl011
Path in Ie)
Tapered Jet Particles in Red Glass
Data of Meade and Jeanloz
Target COl1figuration U~;ed to Recover P8rlnJner1tly Denslfied Fw,ed
Quartz
(A) Static Radiograph of the Crystalline Quartz Target: (B D) Are Cross Sections of Itw Target III (A) Showing Cavity Closurl:
VI
28
29
30
31
II
34
39
40
41
43
ACKNOWLEDGMENT
The authors are indebted to Dr. W. Bruchey who obtained the analysis of red glass, and to
Ms. D. Montiel who provided the SEM micrograph of red glass which appears as Figure 26B.
vii
ACKNOWLEDGMENT
The authors are indebted to Dr. W. Bruchey who obtained the analysis of red glass, and to
Ms. D. Montiel who provided the SEM micrograph of red glass which appears as Figure 26B.
vii
IN II- NT IONAI.LY LFFT BLANK.
Vlll
IN1~NrIONAU Y LFFT mANK
VIII
1. INTRODUCTION
Experiments performed at the Carnegie Institute of Technology (CIT) during World War II
showed that glass has an unusual ability to resist penetration by shaped charge jets. After
World War 11,Pugh and his associates at CIT studied the performance of glass targets and
established general principles (Heine-Geldern 1954; Allison 1960) that apply to the use of
glass for shaped charge protection. However, the physical behavior underlying these
principles remained obscure. The studies described in this report were undertaken to identify
dynamic behavior responsible for the effectiveness of glass targets.
As an introduction to the recent studies, it may be useful to examine Figure 1, which is a
photograph from a 1955 publication (Zernow and Hauver 1955). This back-lighted photograph
shows an unconfined glass target as it is penetrated by a small copper jet. The most
prominent features in the photograph are (A) the central dark region, (B) the dark envelope
that resembles a bow wave, (C) the envelope of trailing fracture, and (D) the impact shock
which is still visible at the lower extremes. The central dark region was assumed to define the
penetration path. The penetration velocity of the jet in Figure 1 is subsonic, so the only shock
wave is the one produced at impact. Consequently, the envelope that resembles a bow wave
must have another origin. Earlier Kerr-Cell photographs at CIT (Pugh et al. 1951) clearly
showed that this envelope encloses a cylindrical volume around the penetration path in soda-
Iime glass.
Concurrent with the CIT investigations, Bridgman and Simon (1953) discovered that fused
quartz and other glasses become permanently densified under static compression at high
pressure. Since that time, many studies of permanent densification under static and dynamic
compression have been conducted, including Viard (1959), Wackerle (1962), Cohen and Roy
(1965), Arndt, Hornemann, and Muller (1971), Gibbons and Ahrens (1971), Anan’in et al.
(1974a), Kanel, Molodets, and Dremin (1 976), Cagnoux (1 981), and Sugiura, Kondo, and
Sawaoka (1981) which are considered most pertinent to the present investigation. In the
present investigation, particles ejected from a fused quartz target during jet penetration were
found to be permanently densified by up to 10O/~. This observation supports the assumption
that the envelope surrounding the penetration path is a boundary between glass which is
1
1. INTRODUCTION
Experiments performed at the Carnegie Institute of Technology (CIT) during World War II
showed that glass has an unusual ability to resist penetration by shaped charge jets. After
World War II, Pugh and his associates at CIT studied the performance of glass targets and
established general principles (Heine-Geldern 1954; Allison 1960) that apply to the use of
glass for shaped charge protection. However, the physical behavior underlying these
principles remained obscure. The studies described in this report were undertaken to identify
dynamic behavior responsible for the effectiveness of glass targets.
As an introduction to the recent studies, it may be useful to examine Figure 1, which is a
photograph from a 1955 publication (Zernow and Hauver 1955). This back-lighted photograph
shows an unconfined glass target as it is penetrated by a small copper jet. The most
prominent features in the photograph are (A) the central dark region, (B) the dark envelope
that resembles a bow wave, (C) the envelope of trailing fracture, and (D) the impact shock
which is still visible at the lower extremes. The central dark region was assumed to define the
penetration path. The penetration velocity of the jet in Figure 1 is subsonic, so the only shock
wave is the one produced at impact. Consequently, the envelope that resembles a bow wJ.ve
must have another origin. Earlier Kerr-Cell photographs at CIT (Pugh et al. 1951) cieJ.rly
showed that this envelope encloses a cylindrical volume around the penetration path in soda
lime glass.
Concurrent with the CIT investigations, Bridgman and Simon (1953) discovered that fused
quartz and other glasses become permanently densified under static compression at high
pressure. Since that time, many studies of permanent densification under static and dynamiC
compression have been conducted, including Viard (1959), Wackerle (1962), Cohen and Roy
(1965), Arndt, Hornemann, and Muller (1971), Gibbons and Ahrens (1971), Anan'in et al.
(1974a), Kanel, Molodets, and Dremin (1976), Cagnoux (1981), and Sugiura, Kondo, and
Sawaoka (1981) which are considered most pertinent to the present investigation. In the
present investigation, particles ejected from a fused quartz target during jet penetration were
found to be permanently densified by up to 10%. This observation supports the assumption
that the envelope surrounding the penetration path is a boundary between glass which is
~5mm~
Figure 1. Photograph of a Glass Target During Penetration by a Shaped Charge Jet.
elastically deformed and glass which has yielded to become permanently densified. In
Figure 1, permanently densified glass resides between the envelope (B) and the penetration
path (A).
Tests were recently conducted with targets of glass and crystalline quartz to obtain further
information about jet-target interactions. These tests used flash radiography and high-speed
photography to observe behavior during penetration. In the tests that used flash radiography,
metallic confinement allowed the targets to be recovered for post-test examinations which
further helped to identify behavior. These recent tests will be described and discussed in the
following sections of the report.
2. EXPERIMENTS AND DISCUSSION
2.1 Test Charge. Most of the penetration experiments were conducted with the jet from a
shaped charge liner with a base diameter of 35 mm. This liner was obtained by reducing the
2
base diameter of an obsolete M9A1 copper cone which had an apex angle of 42” and a
nominal wall thickness of 0.89 mm. The explosive was unconfined Composition B
(diameter =35 mm) which extended to 1.5 tin]os ttlc cone height. This explosive was initiated
by a PBX booster (diameter = 19 mm; height 13 mln) in combination with an Ml 8 detonator.
An earlier study (Hauver and Benson 1955) showed that an Ml 8 improves the axial symmetry
of a detonation wave, mainly by restricting the area over which the booster is initiated. The
primary detonator contained PETN powder wtlic!l was initiated by an exploding bridgewire.
The velocity of the jet tip was approximately 7,830 Ills, and during free flight, breakup
occurred approximately 20.7 y.s after the jet emOrg[}d from the base of the liner, producing
particles with an average length of 2.6 mm (Franz and Lawrence 1987).
2.2 Examination of Penetration-Time D<~a]. Data for depth of penetration as a function of
time were always examined with the aid of a Modified Bernoulli Model (Tate 1967, 1969),
assuming a virtual origin and a linear distribution of velocity along the jet. The jet was
assumed to elongate until the breakup time determined experimentally during free flight in air.
At breakup, the jet was subdivided into segments with the average length determined
experimentally. During free flight, segments were assumed to maintain both their assigned
length and their axial alignment. In metallic targets. the target-strength term in the model is
defined as the quasi-static pressure, R, required to open a spherical cavity frorm zero initial
radius. In applying the model to glass targets, R was considered only as a measure of
resistance to penetration, and it served as a fitting parameter. In this method of application,
values for R were clearly dependent not only on the target material, but also on jet behavior
and details of the jet-target interaction. Basically, the simple model has no realistic means for
treating the complexity of penetration in a glass target. Despite a loss of fundamental
significance, values of R were useful for comparing one test with another, and for locating
changes in penetration behavior during a single test. Reasons for changes in the value of R
were then subject to interpretation based on experimental evidence. The stress unit is
included with R values cited in the text, as a formality, but it is omitted in figures where
relative magnitudes of R are of primary interest.
2.3 Flash-Radiographic Observations During Jet Penetration. Jet penetration into targets
of fused quartz and crystalline quartz was observed by 450-kV flash radiography. Targets for
the flash-radiographic tests are shown in Figure 2. Although target configurations (A) and (B)
3
base diameter of an obsolete M9A 1 copper cone which had an apex angle of 42' and a
nominal wall thickness of 0.89 mm. The explosive was unconfined Composition B
(diameter = 35 mm) which extended to 1.5 time:; the cone height. This explosive was initiJ.ted
by a PBX booster (diameter = 19 mm; height 13 mm) in combination with an M18 detonator.
An earlier study (Hauver and Benson 1955) stlowed that an M18 improves the axial symmetry
of a detonation wave, mainly by restricting the mea over which the booster is initiated. The
primary detonator contained PETN powder whictl was initiated by an exploding bridgewire.
The velocity of the jet tip was approximately 7,830 Ill/s, and during free flight, breakup
occurred approximately 20.7 ~tS after the jet emerged from the base of the liner, producing
particles with an average length of 2.6 mm (Franz and Lawrence 1987).
2.2 Examination of Penetration-Time QQ1r Data for depth of penetration as a function of
time were always examined with the aid of a Modifil~d Bernoulli Model (Tate 1967, 1969),
assuming a virtual origin and a linear distribution of velocity along the jet. The jet was
assumed to elongate until the breakup time determined experimentally during free fligtlt in air.
At breakup, the jet was subdivided into segments with the average length determined
experimentally. During free flight, segments were assumed to maintain both their assigned
length and their axial alignment. In metallic targets. the target-strength term in the model is
defined as the quasi-static pressure, R, required to open a spherical cavity from zero initial
radius. In applying the model to glass targets, R was considered only as a measure of
resistance to penetration, and it served as a fitting parameter. In this method of application,
values for R were clearly dependent not only on the target material, but also on jet behavior
and details of the jet-target interaction. Basically. tile simple model has no realistic means for
treating the complexity of penetration in a glass target. Despite a loss of fundamental
significance, values of R were useful for comparing one test with another, and for locating
changes in penetration behavior during a single test. Reasons for changes in the value of R
were then subject to interpretation based on experimental evidence. The stress unit is
included with R values cited in the text, as a formality, but it is omitted in figures where
relative magnitudes of R are of primary interest.
2.3 Flash-Radiographic Observations During Jet Penetration. Jet penetration into targets
of fused quartz and crystalline quartz was observed by 450-kV flash radiography. Targets for
the flash-radiographic tests are shown in Figure 2. Although target configurations (A) and (B)
3
—————
38mm
DIAMETER
__-L.-—._.ALUMINUM
—
II
I
‘!=------ 102“m ~— .—
STEEL
38rnm
DIAMETER
ALUMINUM
7075T6AL
I
B
Figure 2. Tarqet Configurations for Radloqraphic Tests.-.
were both used for tests with fused quartz, only configuration (A) wos [Iscd for tests wIttl
crystalhne quartz. “[IIc small size of ttIc jet (1 O 1,5 rnnl dlanletcr), tllc l~?;lterl(~l of thu jet
{c;opper~, tlIe relatively Iargu x r,l’y $,OLJFCC SIZC (5 O ITIIII dl:j[ll(:tl’rl. :Illd :;[; clttcr(:d fcidl:itlorl
contributed to imagng pro ble[~ls, arid httle detail could bu discerned befort~ tr:~cer materl;]l was
introduced into targets. Different tracer materials and configur:ltions w[:rc tcstod. and
rad~ographs of jet penetration into targets containing tracers arc showrl irl ~ lgur(} 3
TIIC target rnutcrlal in F-lgure 3A IS fused quartz with a den:;ity of 2.2(1 FJIg[11’, and tt]c
tracer material is lead glass. Penetration has proceeded from top to bottoin Irl the figure
Although pcnetratlorl has advanced beyond the lower tracer, dctwls rlear tl]e punetratlor) frorlt
are not well de finccl and the jet can be resolved only {above th~> upper tracer where It is clcnrly
disrupted. Tracer rnaterl:il has flowed Into th[~ target (toward the bottom of tllc figure) and
dcflncs portions of the penetration path. Displaced tracer rT]~]tcrl;]l IS not concentrated :Ilo IIg
4
: _ [ A\UMINUM I
--r--~ . ----1 F -~-r--,--
i STEEL_ I I , I r--------~
38mm DIAMETER
ALUMINUM
7075T6 AL
---------------.--. ------'
A
~-------I I ,
----102 mm ------'1
I STEEL ------r-
I 7075T6
I AL
38 rnm I DIAMETER I
i'l.LUMINUM L---____ ~ ____ . __ ~ _______________ _
B
r.:.igure 2 Target Configurations for RadiographicTests,
were both used for tests wiHI fused qU3rtz, only configuration (A) WZ1S lls(;d for u;sts wiO]
crystalline quartz, -rile small size of ttle Jct (1 0 1,5 1111ll diameter), Hie 1]1(!tIHIZll ot tilL: Jl;t
(copper), \tIt: rt;latlvely largf.; j ray ~jource Sill: (50 ITHli dlallll:tl'!I, ~lI1d ~;cdttL:r(;d r,ldl~ltlon
contributed to imaging problems, ,md little dutail could bu discerrwd beforl: tracer material was
introduced Into targets Different tracer materials and configurrltions we:rl! tc:stf'd, and
radiogr3phs of Jet penetration into targets containing tracers ar,; shown in r-igure 3
TIl(; target matcri31 in F~igure 3A IS fused qU3rtz wiHl a den~;ity of 2:?O ~J1grll', and ttlL:
tracer material is le3d glass Penetration has proceeded from top to bottorn In tlw figurL:
Although penetration has advanced beyond tile lower tracer, dl!talls rwar Hll; pL:rwtratioll front
arc not well detinuel and Ole Jet can be resolved only above tiw uppc;r tracer wllere It is CII;iUly
disrupted Tracer rnaterial has flowud Into the target (toward Oil; bottorn of tile figure,! and
duflrlCs portions of ttw penetration pan] Displaced traCL:r 1T1;l!l;rlal is 110t COIlCL:lltratod alollg
4
r-IOmm -l
Figure 3. Flash Radiographs Showing Jet Penetration Into (A) Fused Quartz and (8) Crystalline Quartz.
5
the wall of the penetration path. The arrows in Figure 3A indicate the location of optical
density measurements across the image of the penetration path, and Figure 4A shows the
density change, ,~D, as a function of distance. A uniform distribution of absorbing material
within the path woulId be expected to produce the dashed profile. The measured profile is
sirnllar, but asymmetry is present and is probably caused by displaced jet lnaterlal Tt]e
displaced jet matcrlal IS seen above the upper tracer, and its location is In qL~allt,itlvc
agrcelnent witt] tllc asymnletry, although the jet carlnot be resolved at tt]e location of derlwfy
measurcmfents Tt]e penetration path between tile two upper tracers has ;] di[il~leter of
:lppr Oxltllrltt?ly .5 rr]l~ wtlif. tl was corlfirnlcd Wt![!rl ttlc rccovc’rcd tilrgt>t w,l$; sf:cl Ion(xj nrld
rT7C;lSU[L?d.
the wall of the penetration path. The arrows in Figure 3A indicate the location of optical
density measurements across the image of the penetration path, and Figure 4A shows ttw
density change, /\0, as a function of distance. A uniform distribution of absorbing material
within the path would be expected to produce the dashed profile. The measured profile is
similar, but asymmetry is present arld is probably caused by displaced jct material Trlc
displaced Jet material IS seen above the upper traccr, and its location is ill quallt<ltlvc
agrc(]lnent with HII: asymmetry, although the wt cannot be resolvf]d at \118 location ot dUII:;lly
mf:a:;urulm;nts TIlE: penetration patti between tllU two upper tracers has () c1izlIllclur ot
apprOxllTldtl:ly 5 rTlll. whidl was COfllirrTl(;d Wll(:fl till: r(]Cl)vcrud target Wd~; sc:ctll)lwd zlild
measured
TliI: tcuc]d III fi(jIHf: 30 is polycrystallirw qUelfl: Willi d dl'rlSlty of 2 (i<l f'l.1CJ Ill" :me) Hit'
tr,lu'r Ill:ltl;II,11 I', LllltdllHl1 CJrblc1c: ((:f,lIlIie I ';old ql,I:;:; tfdCl;r:~ Wl:f(: Ilot u:;l'd 1!1 (lrd .. 'r tu
i',·()"j ,lilY C1II';lIl1c'rpI':LltICHI tlidt 11l1(]llt rl;';ult f!UIII tlt:I'dVIUI clldldrtl:rl:;tl(. of ql,l:', f"'III'tl,I1I I.'11
:1:(0 II t·Ll!'::." q::,I'L~ ,1PPfl,tr', tu r)C 1110[(; COII/l;lltluILII ttldll Pl;'llItfdtIOIl ,11(11 lu' I'd qu.IrL'
rill' ,t I ,If' tH' (II" IIIJ w;I:i'rj ,It !II<' IWI]fltrdtloll flll!1 ,lild III Ilt'll II dl:~pl,11 I'd trUI'i tilt' 11.'lltl.:1
tl,IU" '!I)pf'cl': t,; i· I i)11l:I'I:t1dtl;ri.ilUllq ttil' r;'l, • .."Iil Till' d"( Iv 1:: i ICj .. 'I; :H I;'d .1:>' !Ii"
:I!: rj(",c':I', 1,'!lHl" \'1,.1 ,I 'IJr'(t!(HI ell ril' j 1"( f' Ti", ti,I;,I!>'I) Ii' ." I" 1111 ',' 1,' ,i· j"
!df'(l1171'(j d,:' '.,t, ;1'::11'1' It· I: 'N(;uld~)I' "'P!',.l\'(] I' It,' u:III'(l 'll ,t.,,, I: \V'" ,"' , !
NIH] d dl,lfTlf 1,;1 Ii! 1 ;' 'Ill" ;F,j .! tllt)1 Wltll ,lI' ;lld' "11 Ill. WII'!! 'I .)1.) q, Iii" 1'1: .,,: I
, ; i' j C ; t I!'; '1 cl :.,!! I d ( Ii' CJ r , I~) Ii! I: r i(] I:;' ~ fJ (h f" '1 () t I: r : .• I ri 1 (i, 'cl I ,"y'! cJ I 'i HY I) ~ :. d. : J i' 1! Jr l '
riurillCJ PI;I'I;\rd\IUI: dltllOuql1 clo:;url Wd'; fOLHId III 111(' rc;covL:rc'd LnC]!:t
TIl(; loc;ltiofl:~ fO' denSity scans In FIC)lJrf;~~ 3 ;Hld 4 WLire flat :1rbrtrclrlly (',I ·illl I! 'CJ 111l'Y
W(}rr: :;(:If:c1(;d to lilw.;tratu 11IO:;t cludrly thfi CpJillt;!tIV(; OIY,l'rvdtloflS about (j,:;tllllllh,rl'; uf I,'t
dnd tingf;t Illd!f,lld, Nillilfl pl;rH;trdti()[l P;]tiIS Ifl fil:;('d qu.Htz dfld uyst;llllll1' qL1,lIt' If] til(' (,1:;(:
of fused l1uartz. thL' most SUitable location was bctwcurl ttw upper two tracers Gec:lLJse of
6
0.( “
‘6m, --..,- -
)0-! I ! 1 I3
1-4 5
UI>IANLL , mrn
A
-0’*8~–- 1 r
-0.06
I d.-,.\
{’ 1\\,’
I
/ \\:
1 T;/
// 1<
-o,02- 1“I!4I
1 1 13 4 5 fi
DISTANCE , mm
B
Figure 4. Profiles of Optical Density Across Pf:tlt:trat!orl Potlls in (A) Fused Quortz ond {B)
Crystalline Qunrtz.
7
o <1
0 <1
-0.10
-0.08
-0.06
-0.04
-0.02
0.000
-0.08
-0.06
-0.04
I
I
I I
I I
I
I
I
I I
I /
\
/ /
\
/
/
/
/
2 3 DISTANCE
A
'- ... , I
\
I \ \
\
I ... 'J 1-
... , , , , , , \
4 mm
5 6
0000!:------------:2~-----:3=---4~---':5~-~6
DISTANCE mm B
Figure 4. Profiles of Optici11 Density Across P(:lldrzll!on Patils in (A) Fused QUZ"Jrtz and (8) Crysti1lline Quartz.
7
low image contrast, a location closer to the upper tracer provided a higher concentration of
tracer material and Improved the contrast for measurements. In the case of crystalllnu quirt~,
the critical location was between the central tracer and the next lower tracer. Qualitatively, tt~e
jet was visible (In the original radiograph) within this entire region. However, tracer matcrlal
was more concentrated close to the central tracer, so the density scan was conducted at Itlls
location where it could benefit from improved image contrast.
Strain fields are observed to be different in the fused quartz and crystalline quartz tarq[:ts
shown in Figure 3. In fused quartz, displacement at the bottom surface of tracers deflncs a
column with a dlarmeter of 9-10 mm which, in high s[lica glasses, corresponds closely to tt~c
diameter of the en~elope containing permanently densified material. In crystalline quartz,
displaced material at the bottom surface of tracers defines a column wtth a larger diameter of
15–16 mm, It is assumed that large displacements in crystalline quartz were associated with
failure Into particle$; or microblocks (Anan’in et al. 1974b) which were subsequently displ:~ced.
Displaced particles should not fit together compactly, and this represents a source of dllatar]cy
ti~at might produce cavity closure However, Figure 3B suggests that cavity closure in
crystalline quartz does not proceed rapidly since there is no clear evidence of closure {it this
stage of the penetration.
2.4 Photo~raphlc hAea SLJre~TICntS -Qf Penc?tral!on Tl[ne. J[:t penctr~tlo[l l!lto glass w;i;
observed by higtl speed photography irl an effort to examine th[: pcnctratlor] pattl n[>ar tt]u
penctrtitior] frorlt wtlcre flasl! radiograpl]s did not provide w[;II d[fIncd f(:,itur~::, 111fu~j IJ,Irt;
Tt~e Inltlal photogr;~plllc studlcs were conductecj wltt~ blocks of fused quart?, but l,~ttr :tuj( :;
used targets of commercial soda lime glass. Thu blocks of fused quartz offered gooc oI)tIL:,iI
quallty and no interfaces where failure could be initiated by the impact shock. However,
fracture propagated at a velocity nearly equal to the penetratiorl veloclty r] fUS(2d quartz nr)d
quickly obscured details near tile penetration front, making this material ;I poor CI1OICC?for
optical studies Despite this short corlllng. fused qu(~rtz was of Interest bt’cciu:;~) If I)c]s b~’(1[1
the subject of ITIJIIy Illgl) pressure studies and offers a dlrcct co[nparson wltt] pcnctratlc[l
behavior in crystalhne quartz. In later tests with sodalirne glass, the penetration vclo[lfy
greatly exceeded the fracture velocity during the early part of penetration. Photographs of tt~e
exposed penetration path in soda-lime glass provided insight into behavior during jet
8
low image contrast, a location closer to the upper tracer provided a higtler concentration ot
tracer material and Improved the contrast for measurements. In the case of crystalline qu,lrt7,
the critical location was between the central tracer and ttle next lower tracer. Qualitatively, the
jet was visible (in the original radiograph) within ttlis entire region. However, tracer rnateml
was more concentrated close to the central tracer, so the density scan was conducted at ttliS
location where it could benefit from improved image contrast.
Strain fields are observed to be different in the fused quartz and crystalline quartz t;lrC)(ds
shown in Figure 3. In fused quartz, displacement at the bottorn surface of trGcers dctrn(;s Zl
column with a diameter of 9-10 mm which, in high silica glasses, corresponds closely to till':
diameter of the envelope containing permanently densified material. In crystalline quartz,
displaced material at the bottom surface of tracers defines a column With a Idrger diameter of
15-16 mm. It is assumed that large displacements in crystalline quartz were 3ssociated witll
failure Into particles or microblocks (Anan'in et al. 1974b) which were subsequently displaced.
Displaced particles should not fit together compactly, and this represents a source of dilatHlcy
tilat might produce cavity closure However. Figure 38 suggests tt13t cavity closure in
crystalline quartz does not proceed rapidly slflce trlCre is no clear evidence of closure Zit tllis
stage of the penetration
2.4 PrlOtographic MeasurerncntsQf PerlQ1f'~ltloJl __ lIiTl_Q J(:t pcnetr,ltloll l[ltO CJI;I~-:;S w;r;
observed by high ~;peed photography in em (;ffort to examine the fwnetratiofl path near till.:
perwtrutlon front wtlere flash radiographs did not prOVide wf;11 o('flncd f(~,itLJrl;~, 1[1 fll'l.:tJ !lUcHt'
Tt1C mitlal prlotoCjr:lptllc studies were conducted Wlttl blocks of fused qUdrtz, tJUt I,lll'r :tUrJd :;
used t3rgets of cornrnerciClI soda lime gI3SS. TIll' blocks of fused quartz otfcr(;d good optlcdl
quality and no interfaces where failure could be initiated by the impact shock. However,
fracture propagated at a velocity nearly equal to the penetration velOCity In fused quartz Zlnd
quickly obscured details ncar the pcrwtration front, making \tlis material (l poor cl10ice for
optical studl(;s Despite \tlis sllortco[ning. fused quartz was of interest oec,lu:;L' it lIas OL:I;[l
the subject of fTJdlly high prussuw studies iHld ofters 3 direct cornp,1rison wltll pcrwtr,ltIC[l
behaVior in crystalline quartz. In later tests Witrl soda lime glass, the penetration vdocity
greatly exceeded the fracture velocity during the early part of penetration. Photographs of tile
exposed penetration path in soda~lime glass provided insight into behavior during jet
8
penetration and made this material more useful for photographic studies, even though
thicknesses greater than 25 mm were not readily available.
2.4.1 Experimental Configurations for Photographic Studies. Representative
configurations for photographic observations of penetration are shown in Figures 5 and 6.
The earliest tests were conducted with back lighting as shown in Figure 5. A plastic Fresnel
lens imaged the light from an exploding wire into the aperture of a high-speed framing
camera. The target was located close to the Fresncl lens and consisted of a glass block,
backed by steel, with a cover of polymethylmethacry late (f MMA). The PMMA cover was
usually 25 mm thick and shielded the glass from debris that might precede the jet.
Penetration in the PMMA was supersonic, allowing the jet to arrive at the glass before other
disturbances that could produce damage. Targets commonly had a 102-mm-square cross
section. Waves reflected from the lateral boundary never produced troublesome surface
damage and did not return to the axis of penetration before measurements were completed,
JET
I
I PMMA
GLASS
GLASS
GLASS
STEEL
CAMERA3VIEW
Figure 5. Configuration for Photographic Tests With Back Liqhtinq,
9
penetration and made this material more useful for photographic studies, even though
thicknesses greater than 25 mm were not readily available.
2.4.1 Experimental Configurations for prlOtographic Studies. Representative
configurations for photographic observations of penetration are shown in Figures 5 and 6.
The earliest tests were conducted with back lighting as shown in Figure 5. A plastic Fresnel
lens imaged the light from an exploding wire into the aperture of a high-speed framing
camera. The target was located close to the Fresnel lens and consisted of a glass block,
backed by steel, with a cover of polymethylmethacrylate (PMMA). The PMMA cover was
usually 25 mm thick and shielded the glass from debris that might precede the jet.
Penetration in the PMMA was supersonic, allowing the jet to arrive at the glass before other
disturbances that could produce damage. Targets commonly had a 1 02-mm-square cross
section. Waves reflected from the lateral boundary never produced troublesome surface
damage and did not return to the axis of penetration before measurements were completed.
JET
~ FRESNEL PMMA LENS
GLASS
* -< CAMERA
~ GLASS VIEW
GLASS EXPLODING WIRE
STEEL
Figure 5. Configuration for Photographic Tests With Back Lighting.
9
*
JETAXIS
L/ CAMERA
VIEW
* -%---- ;;:):;
JTOP VIEW \ EX&;PL.:lNG
WHITEREFLECTOR/
DIFFUSERJET
SHIELD
GLASS
‘J “
CAMERA
VIEWGLASS
GLASS~ EX&:PL:lNG
STEEL
SIDE VIEW
Figiure 6. Configuration for Photoq raphic Tests With Front Llqhtinq.
10
JET AXIS
~
TOP VIEW
WHITE REFLECTOR!
DIFFUSER JET 1-
PMMA
GLASS
GLASS
GLASS
STEEL
SIDE VIEW
~ CAMERA VIEW
• ~OPAQUE SHIELD
\EXPLOOING WIRE
/S
k~ ~
HIELD
~ CAMERA VIEW
EXPLODING WIRE
Figure 6. Configuration for Photographic Tests With Front Lighting.
10
Damage that limited photographic observations W;IF lt~,-ir:+ct[>ristlc[ally imtiated close to the axis
of penetration at interfaces or imperfection:’ ir~ III(: .:i.::lC Unfortunately, the permanen!ty
densifled region around the penetration patl :!rI.?Wr;iYrf!fractcd the back light and prevcrltcd
critical observations. Consequently, ttle frorll i ,! I II ?I:st conflguratiorl in Figure 6 was
introduced to overcome the refraction proti~l~l, .{ .,.: ~!~xf wittl back Iigtltlng. Front Iigtlting
was providc?d by exploding tungster~ wire:, ~!t ‘ ,A;..i~ : Iliclded frorr~ dirt?ct observation by tt]u
‘}[~ wt:]k, diffust;d back lighting incanlwa A whd(? card at the bock of th[? tnrk~!l ~:r:. :...
acfditiotl to tile strong front lighting, and ttll: ~ ~:. ~~‘:’i was judg~?d to provide the rllo$t
complctc photograpl}lc detail.
Glass targets were photographed durir!!} p , !:i~[] by t)otl] corltlnuouss and partlculatc[j
jots. In all tests to be reported, photograph:; wt.: ~ ,,.,. !.,‘ {~’] ,]t 1 ps intcrv:ds. When tt]e standoff
distance was approximately 140 mm, j[?t bri:~~ . i ur~(’[j tjuring penotratlon in the tt~ick
PMMA cover and p[?netration in the glass wi~L ;.::!:t,;y by Jet s[?grllents or particles. When tllc
standoff distance was approximately 50 mnl, I!!C j~:[ usu;]lly remained continuous throughout
all of the observed penetration into glass.
2.4.2 Jet Penetration Into Fused Quartz I IJ(I;,I 7 shows penetration] tilnc data obtained
by high speed photography during jet penctr;~timl Intl.: [I!onolitllic fused quartz. Jet breakup
occurred during penetration in the PMMA cover. Ttw penetration model generated a
penetration path in agreement with the experirllt’ntat d,~ta when the assigned target resistance
was 11 GPa. After approximately 10 ps of pen[;tr(itltirl into fused quartz, the experimental
data began to deviate slightly from the calculat[xf penetration path. Agreement with the later
data points was achieved by assigning a higl~(?r rcwstance value of 22 GPa. Photographic
measurements ended at approximately 16.3 ps when the penetration front was overtaken and
obscured by trailing fracture.
Flash radiographic tests, reported in Section 2.3, provided a few measurements of the
penetration depth in fused quartz after fracture obscured the penetration front and ended
photographic measurements. In Figure 8, these radiographic data are combined with the
photographic data. The radiographic data on Curve A were obtained from tests with Target A
in Figure 2; the one datum point on Curve B was ot~tainc?d from a test with Target B. For
11
Oamage Olat limited photograp~lic obscrvatlufh W;l~, I .. ll<1rdcteristically initiated close to Hw axis
of penetration (1t interfaces or imperfection~; In til[;lt.l:,c, Unfortun(ltely, trw permanently
densified region (1round the penetr(1tion p;lth ~;tr'Ylqiy rrdractcd th(~ back light (1nd prevC'rltud
critical observations. Consequently, tile frem! : :~i(.d t!~sl configuration in Figure 6 was
introduced to overcome the refraction probl/'il\ Y' '~'" !kd with back lighling. Front ligtlting
was provid(~d by exploding tungsten wirc~;\'\il" "">,, :11Il:lded troln direct observation by tile
camer;l A wtlite card 3t ttw back of the t:Jlq:': ,'r,\\ ,j,'d wl~,lk, diffuSL~d back ligtlting in
additioll to tlw strong front lighting, and Uli~ ., t 'hi'] was judged to provide thu most
complete ptlOtographlc detail.
Glass targets were pl1otograptlcd durirH) 1,,1, HI II tly twill COlltlrllJOLJS c!rld paltlculatl:d
jets. In all tests to be reported, ptlOtograptl:; liV,: l' tdk'll ,It 1 ps intervals. Wilen Hw stzllldoff
distance W(1S approximately 140 mm, jut brl;'~.' if' (H,UIIL'rJ during pmwtration in tlw thick
PMMA cover and p(~netration in ttle glass Wej' t 'fib Y by In! segments or particles. Wt,cn ttH!
standoff distance was approximately 50 mill, \! !L~ 1(:1 lIsuzllly remained continuous ttHoughout
all of the observed penetration into glass.
2.4.2 Jet Penetration Into Fused Quartz f l'lll!l' 7 shows penetration time data obtaim~d
by high speed photography during jet penetration In!,) 11!orlolitilic fused quartz. Jet breakup
occurred during penetration in the PMMA COVl:r. Tile penetration model generated a
penetration path in agreement with the experinwntal dolta wtwn the assigned target resistance
was 11 GPa. After approximately 10 ps of pcnl~tr<ltIOf1 into fused quartz, the experimental
data began to deviate slightly from the calculalt~d penetration pattl. Agreement with the laler
data pOints was achieved by assigning a higtll~r rW;lstClnce value of 22 GPa. Photographic
measurements ended at approximately 16.3 ~IS wtlcn tile penetration front was overtaken and
obscured by trailing fracture.
Flash radiographic tests, reported in Section 2.3, provided a few measurements of the
penetration depth in fused quartz after fracture obscured the penetration front and ended
photographiC measurements. In Figure 8, these radiographic data are combined with the
photographic data. The radiographic data on Curve A were obtained from tests with Target A
in Figure 2; the one datum point on Curve B WClS ot1tained from a test with Target B. For
11
T1
IT
11
I
NN
\\&
\f
\\‘t\.
\’c.~
U-)
‘...\Ld
‘\:
‘k\
“\\~
‘..,
,J
UJLU
‘N
OllV
&j13N
3d
70
60
E E 50
z 0 f-- 40 <1
--'- 0::: rv
f--W Z 30 w CL /
/
20
10
.)"
-~----~~--------"-.,----------~
~R=II
10
TiME,fL S
/.o",~ /.d#.' ~R=22
//
FUSED QUARTZ --- - -
PMMA
15 20
EE
zo
t=21-LdzuCl_
5(
c
FUSED Q.UARTZ .._.. . . . .STEEL
001 I
50 100 150
Figure 8.
TIME , /LS
Combined Radiographic and Photographic Data for Jet Penetration Into FusedQuartz.
E E
z
150
o 100 I-« 0::: IW Z W 0..
50
---c
_______ 8
-...(')--A
__ ~_USED Q_l)ARTZ STEEL
°0~------------5~0~------------1~0-0------------~150
TIME, fLs
Figure 8. Combined Radiographic and Photographic Data for Jet Penetration Into Fused Quartz.
13
refererlce, Curve C IS an extrapolation of data at the beginning of penetrtition in Figure 7,
wtlcre the assigned target resistance was 11 GPA Radiographic data con flrn]cd a subst:ultlal
increase in target resistance during jet penetration into fused quartz, in agreement with !hc
minimal photograph evtdence for such an increase. Target A became r~lore resistant to
penetration than Tar’get B. TIICSC target configurations provided stmilar lateral confine[~lcr]l for
the fused quartz core, but Target A provided better confinement by tt]e frorlt steel plat{?. An
cxarnination of re~ovured targets revealed that as the steel plate In Target A W:N pcnutrat(;d.
radial deformation caused engravcment into tile surrounding alul II Inu ITl, keeping It in plac~?. In
colmp; ~rison, the steel plate at the front of Target B bulged outward, reducing tt)c con finerllcnt
of core material.
In Figure 9, penetration into fused quartz IS compared with punctuation Into crystalline
quartz, The curve ior fused quartz (FQ) is based on both the pl]otograpl]iu data and tllLI
radiographic data obtwn(.:ci wltll Target A. Tflc curve for crystalline quartz (~(l) IS based
solely or) one ra{~lc(gr;~pt~lc [r]~’asur err lent wittl T,arget A. By assigrllng crys!:llllrle quartz a
target resistance of 14 GPa, the model provided close agreement with both ttl[: radlograpt]c
datun) point ar-d the final deptt] of p[,?netration measured in th[: recovered targt?t. This
agreement suggested that cavity closure, found in the recovered target, dld not occur quickly
enough to have a slgnlflcant In flucr]ce on jet penetratiorl into cryst:~lline quartz In Flgurc 9 lt
is apparent ttlzt fused quartz. early irl tt~c pcl]etratlorl, becomes ,] f)lorc r[::;l:;!;irlt t~]rgt:t
material than crystalline quartz
Although Illgt] :;pccd pt~otograptly was able to provide penetration !irnc data for fused
quartz, tl]c r,pd propagation] of trailrng fracture alw;?ys prevented obs[; rva!lorls of tt)e
penetration path IP the rl:glon bc!hnd tile pcflctrallon front wtlcre d[.:twls were poorly duflr]cd in
fla:,tl radiograph):, a(Ici wtlcrt; lrlforrl);~tior) was neudcd to cx.~)l:]ln t!]c incru,~:;u III t:irgct
resistar]ce durirlq jut pcnetr; itlor) Borosil/cat~; glass allowed r])orc of tllc pl’nctratlor~ path to
be observed, Lut ptlotograplls by Zcrnow and Hauvcr (1!355) arid by Pugt] et ~1. (1951)
$;t]owcd a grcatur i{~r]gtll of the penetration path than could be observed wltl~ borosllicate
glass. The greatest observed path Icnglh implies the lowest rate of fracture propagation
wtlictl would nlahe suet] a glass most suitable for photograptllc observ~~tions The g[aSS USUd
by Zernow anc Hauver was recently analyzed and Identified as a sodallnlc composition
14
relen.mce, Curve C IS 3rl extrLlpolatlon of data at the beginning of perwtr(Jtion in Figure 7,
where the assigned target resist3nce was 11 GPA Radiographic dat3 conflrrlll;d a substantial
increase in target resistance during jet penetration into fused qU3rtz, in agreement with trw
minimal photograprl1c evidence for such an increase. Target A became morc resistant to
penetration ttlan T~lrget 8. These target configurations provided similor loteral confinerllL'f1t for
the fused quartz core, but T;:1(get A provided better confinement by tt18 frollt str;el plate. An
exarnination of recovured torgets revealed thdt as the steel pldte in Target A was perwtratc;d,
radiol deformotion caused engravelTlent into trle surrounding aluminulll, kc(;ping It ill placl' In
comparison, the stuci platu dt ttle front of Tdrget B bulged outwdrd, reducing ttlt: confirWl111;nt
of core mdtericll.
In Figure 9, pr.:rwtration into fused qUdrtz IS cornp;m:d with pc:netration Into crystalline
quartz. Tr18 curve tor fUSI:d quartz (FO) is based on bottl trw pflotograprlic.; dal3 and ttl(;
radiograpfllc data obtalrwd Wlttl Target A. Trw curve for crystalline quartz (CO) is bZ1sr::d
soltJIy on one rddl(X]faprllc rnuaSUWrTI(:;nt Wiltl T;1(get A By assiCJfling cry~;talllllC quartz a
target resistance of 14 GPa, the model provided close agreement with bOttl ttll: radiogrdptllc
datum point al',d ttw final depttl of p(;netratioll measured in trw r()cover(Jd tarot:! This
agreernent suggested thZ1t cavity closure, found in the recovered target, diu not occur qUickly
enough to have a ~;Ignrficant Illflueflcu on jet penetratioll into crystalline quartz In Flgur(; ~), It
is apparent ttl;;! fu~;ed quartz, early In tile fJl'llctratiorl, becornr:s d rnorl; 1(~:;I:;LHlt tLHgl.:t
rna te rial ttl an cry:" tilll i ne qu artz.
AltrlOugrl high ;;pecd ptlOtography was able to provide penetrZ1tion tilile dZlta for fused
quartz, the lapld propagatiorl of trailing fracture always prevented observatlolls of ttle
penetration path In the rl:gion berllrld ttle pc:nutratlon front Wflr;ru de:taiis WUrl: poorly dufincd in
flash r(]dlogra~fls and wlll:rl: Irllorlnation was rwc:dud to expl;Jln ttlC irlcrudSu III Urg(;t
resistance ciUrlrl~] Jut penelldllon Oorosilicdtl! glass allowL:d I110le of ttll: p,:rletrzltloll pattl to
be obsl:rved, t,ut ptlotograplls by b;rrlOw dnd Hauvu( (1955) zHid by F)Ugtl et al. (1951)
c;rlOwcd a gruatur Icmgltl of ttw punetration patti than could be observed wltll borOSilicate
glJSS The grl'atl;st observed path length implies the lowest rate of fracture propZ1gation
Wilictl would maku sUetl a glass most suit3ble for photographiC ooserveltiolls TrlO glass usud
by Zernow anc Hauver was recently analyzed and Identified 3S 3 sodallfllC composition
14
E 10E.
1-aCK
LIJ 5(n
c
1 1
I
CQ
-- 0 --FQ---~-/“.-
QUARTZ—..STEEL
. . . --—— .
I
)I
50 100 1!TIME , /AS
Figure 9. Comparison of Penetration-Time Data for Jet Penetration Into Fused Quartz (FQ)and Crystalline Quartz (CQ).
15
150~------------~--------------~--------------~
EIOO E
z o ~ 0::: ~ W Z w 50 a..
I I
/
/ /
/
,0 , /
/
50 TIME, f-Ls
CQ
_-0-- FQ
QUARTZ ----
STEEL
100 150
Figure 9. Comparison of Penetration-Time Data for Jet Penetration Into Fused Quartz (FO) and Crystalline Ouartz (CO).
15
without the ferric-ion impurity that commonly imparts a green color to thick window glass. The
glass used by Pugtl et al. was identified as commercial soda-lime. Photographic
measurements of penetration-time were conducted with both types of soda lime glass.
2.4.3 Jet Penetration Into Soda-Lime Glass, Most of the photographic studies with
soda lime glass were conducted with front lighting, and the basic configuration IS stlown in
Figure 6. The standoff in most tests was approximately 140 mm, and in these tests the glass
was penetrated by a partlculated jet. Two tests were conducted with a shorter standoff of
approximately 50 mm, and in these tests the jet was continuous throughout nlost of ttlc
photographic sequence. One test was conducted with the soda lime glass without ferric Iorl
impurity. Tt~is test was of interest because the glass was monolithic and cor]!:]lrlud st)lall
bubbles. All other tests were conducted with commercial soda Iirne plate whIct) had (i
thickness of 25 mrm Tests with a continuous jet will be described first
Flgur[> 10 shows sequential photographs of a continuous jet pcnctratlng 25 rl~rn tlllch
plates of soda Ii[llr- glass. Photographs were at 1 ps intervals and were t;~ken will] s,tror]g
front Ilghtlng and weak back hghting. These photographs show the boundary of tilt:
penetratiorl path, tllc per[nar]cntly denslfled volun~c surrou[ldlrlg ttlc pt?r]t;tr,]tl[[~ p,ittl, ttl~
trwling fr:lctlurc :~r’d Il]e fracture inltl;]t~.:d at ;I borldcd intcrf, icc hutwc[’rl [; I,V-I ;)I,III;: TI:,)
penctr; ~tion pat}) IS observed to op[:r] and t!l[:n p~rtially CIOSC Slr)c[> ~!~~-![(’ l.(’(’!)r: t)l.’t~)r(? [tl(
surrounding glass undergoes brittle fwlure, It IS concludud tl~at closure IS prir~~,irlly i[so(witcd
with recovery from high pressures near the pcnctratlorl front. Tf]c boundary of ttle
permanently dcnslfied volume, whict] IS initially at the yield stress, displays slrqtlt n(;cklr]g as a
result of elastic rccovcry. The boundary Iaycr of the penetratlor~ pattl IS tllc or]ly p,]rt ot Itlc
targ[:t that is recovered intact Surrourld[ng !argct material foils Into p;~rtlclt;s w!)IcI) ,Irc
disp(;rc(-+d by ttlc blast, wtIIlc nl;]tcrioi in the pcn[?tratlotl paf!l is higtlly ~IIot}ilc tirlcl t):ti~I~L:; w;
the target fails. TIIe heated boundary layer is sufficiently plastlc to resist brlttlc f,]ilurc :~IId
survives with recognizable features. This boundary layer was found to have :1 tl~lckr]c:;s of
approximately 1 mm.
Figure 11 shows penetration fime data for the test pictured in Figure 10. All of tt~e
experimental data are In close agreement with a curve generated by the penetration Illodcl
16
without the ferric-ion impurity that commonly imparts a green color to thick window glass. Tr10
glass used by Pugh et al was identified as commercial soda lime. Photographic
measurements of penetration time were conducted with both types of soda lime glass.
2.4.3 Jet Penetration Into Soda Lime Glass. Most of the photograpr1ic studies with
soda lime glass were conducted with front lighting, and the basic configuration is shown in
Figure 6. The standoff in most tests was approximately 140 mm, and in Hlese tests ttw glLlSS
was penetrated by a particulated jet. Two tests were conducted with a shorter standoff of
approximately 50 mm, and in these tests the jet was continuous throughout most of tile
photographic sequence. One test was conducted with the soda lime glass without ferric ion
impurity Ttlis test was of interest because the glass was monolithic and con\;lIflL:u :~1llall
bubbles. All other tests were conducted with commercial soda lime plate wtllch tlad a
thickness of 25 mm. Tests with a continuous Jet will be described first.
Figure 10 shows sequential photographs of a continuous jet penetr3ting 25 1111ll tllick
plates of soda lillll glass Photographs were at 1 ps intervals and were takell with strollC]
front ligllting and weak back lighting TllOse photograprls show ttlC boulld~1ry oj till;
penetration path, tll(~ permanently densifled volunw surroullding tlw Pl;lll:trdtloll fJdtll till;
trailing fr;Jcturc:, dnd tiw fracture illitiilt'.:d at a bondl:d illtcrL1Ct; hetvvl;(;ll CJI;t:~:~ pl,lk:: Ti:!'
perwtrdtiorl path IS observl.:d to opell and tiH;n partially clos(; Since clo:',:JrI' C(lJr:: h,·tcHI; ttl(:
surrounding glass undergoes brittle failure, It is concluded ttlat closure IS prilll,trlly d';SOll,lku
with recovery from 11igh pressures rWilr trw penetratlorl front. The bourldary of ttw
permanently dcnsified volume, which IS initially ilt trw yield stress, displays SllQllt Ill~cklf1CJ as a
result of elastic rf.:covcry. Ttw boundary layur of tlie pcnetr;]tlon patll IS the Gilly pdr! of HIL:
t1rg(~t Hlat IS recovered Intact Surroulldlng t;lrget rTlJteriill fCliis Into p;Jrtlclc's wlliell ,H;.'
disp(;rsf:d t)y til(': blast, willie lTlatenal in tllU p(;lwtratioll patti IS lligtlly l!lobile; ,Hid (':'CclrW,; ;):~
trle target fails Tile Iwated boundary layer is sufticiently plastiC to resist brittle fdilure ZUlU
survives witli recognizable features. This boundary layer was found to have (j tillcklle~;:~ of
approximately 1 mm.
Figure 11 S~10WS penetration time data for the test pictured in Figure 10 All of tile
experimental data are in close agreement with a curve generated by the perwtration l110del
16
;;~~~ ,
.~!S .\ ~.:.. : .... f •
t
u
<tl I E E o
I J
17
l -VJ
~ -Q) ..., VJ :::J o :::J ,~ C o
(!) U
.0 c .Q 1ii ~ Q) c Q)
c.. c 'C :::J o
LL. ~ VJ VJ ro (5 Q)
E ::; tb 'lJ o
(J)
a
1I
II
II
II
#I
-lA
af-
00
vw
u)In
em
%
UJU
J‘
NO
llVM
13N3d
u
1-
18
70
60
E 50 E
z o 40
~ a::
...... ~ (X) w 30
Z w a...
20
10
5 10
TIME , J-LS
15
SLG-2
SLG-I
PMMA
Figure 11. Penetration-Time Data for the Jet Penetration Shown in Figure 10.
----
20
with R = 7 GPa. There is no evidence of an increase in target resistance such as detected
with fused quartz in Figure 7. Jet breakup, based on free-flight observations, is indicated on
the penetration path and should have occurred at the end of the photographic sequence in
Figure 10. Frame H in Figure 10 does show an irregularity at the end of the penetration path
that resembles penetration by a jet particle. Later, similar features will be observed during
penetration by a jet that is definitely particulate.
The target configuration in Figure 6 was modified for a second penetration test with a
continuous jet. Thickness of the PMMA cover was reduced to 3.2 mm and a 25-mm thickness
of steel was added at the front. A hole, 4.8 mm in diameter, was drilled through the steel to
admit the jet. It was anticipated that the confinement provided by this steel plate would
enhance path closure close to the PMMA-glass interface. Sequential photographs from this
test are shown in Figure 12. When compared with the photographs in Figure 10, the
penetration path in this test is highly asymmetrical, with protrusions and regions of intense
self-luminosity that were not observed in the preceding test with a continuous jet. These
features suggest a greater interaction between the jet and the glass target.
Figure 13 shows penetration-time data from the second test with a continuous jet. Data
during the first 9 ps of penetration into glass were in agreement with a curve generated by
assigning a target resistance of 7 GPa. However, the target resistance then increased
abruptly and a value of 40 GPa was necessary to produce agreement with the final three data
points. Jet breakup should have occurred after the final point.
Photographs from both tests with a continuous jet were measured to determine how the
diameter of the penetration path, including the boundary layer, varied with time. Path
diameters were measured at approximately the same location in each test, and the locations
are indicated by arrows in Figures 10 and 12. In Figure 14, the path diameters are plotted as
a function of time. In the first test, which had a highly symmetrical penetration path, the path
opened to its maximum diameter in 2 w and then partially closed before fracture obscured the
measurement location. In the second test, the diameter began to deviate from the trend of
the first test at 2–3 p.s, and reopening was clearly established at 5 ps. It is assumed that this
resulted from an interaction with elements of the jet behind the penetration front. In Figure 15,
the penetration path from Figure 13 is replotted along with a path for the jet element that
19
with R = 7 GPa. There is no evidence of an increase in target resistance such as detected
with fused quartz in Figure 7. Jet breakup, based on free-flight observations, is indicated on
the penetration path and should have occurred at the end of the photographic sequence in
Figure 10. Frame H in Figure 10 does show an irregularity at the end of the penetration path
that resembles penetration by a jet particle. Later, similar features will be observed during
penetration by a jet that is definitely particulated.
The target configuration in Figure 6 was modified for a second penetration test with a
continuous jet. Thickness of the PMMA cover was reduced to 3.2 mm and a 25-mm thickness
of steel was added at the front. A hole, 4.8 mm in diameter, was drilled through the steel to
admit the jet. It was anticipated that the confinement provided by this steel plate would
enhance path closure close to the PMMA-glass interface. Sequential photographs from this
test are shown in Figure 12. When compared with the photographs in Figure 10, the
penetration path in this test is highly asymmetrical, with protrusions and regions of intense
self-luminosity that were not observed in the preceding test with a continuous jet. These
features suggest a greater interaction between the jet and the glass target.
Figure 13 shows penetration-time data from the second test with a continuous jet. Data
during the first 9 JlS of penetration into glass were in agreement with a curve generated by
assigning a target resistance of 7 GPa. However, the target resistance then increased
abruptly and a value of 40 GPa was necessary to produce agreement with the final three data
pOints. Jet breakup should have occurred after the final point.
Photographs from both tests with a continuous jet were measured to determine how the
diameter of the penetration path, including the boundary layer, varied with time. Path
diameters were measured at approximately the same location in each test, and the locations
are indicated by arrows in Figures 10 and 12. In Figure 14, the path diameters are plotted as
a function of time. In the first test, which had a highly symmetrical penetration path, the path
opened to its maximum diameter in 2 JlS and then partially closed before fracture obscured the
measurement location. In the second test, the diameter began to deviate from the trend of
the first test at 2-3 JlS, and reopening was clearly established at 5 Ils. It is assumed that this
resulted from an interaction with elements of the jet behind the penetration front. In Figure 15,
the penetration path from Figure 13 is replotted along with a path for the jet element that
19
C\J -u u. '" Q)
f-
a; --,
'" ::;)
0 ::;) c "" c 0 U
'" .0 c 0
~ ~
a;
"l c
CD Q)
a..
~
'" f-
'" '" '" (3 Q)
E :::i ,
'" "0 0
<l Cl (f)
'" '0
f '" .r:
'" E ~
E 0
Q 0
1 .r: a..
C\J
Q) ~
::;)
Ol u::
20
II
3.-g1-
21
I\) .......
60~------~------------~--------------~------------~----,
50
40 E E
.. 30 Z 0 r <{ 20 a:: r w z w 10 a..
o
-10
-_.-----
~-
~.
o 5
~
, /,' ,BREAKUP " ---,- -_._-
.~FRACTURE ~ V=1960m/s
SLG-2
SLG-I PMMA
STEEL ----
(DRILLED TO ADMIT THE JET)
10 15
TIME, lis
Figure 13. Penetration-Time Data for the Jet Penetration Shown in Figure 12.
t I I 1 1 I 1
6 -
#
t
00I
I 2 3 4 5
-\\
“’’A-...---A- 1
A 25 mm PMMA COVERo DRILLED STEEL COVER
1
6
TIME , ~S
Figure 14. Path Diameter as a Function of Time (Continuous Jets}.
arrives at the transition point where the target resistance increases. This jet element reached
the location of diameter measurements approximately 2.3 p after the tip. This time is in
general agreement with the 2=3 ps time at which the curves begin to deviate in Figure 14.
Two factors probably contributed to features of the penetration path in Figure 14. First,
the presence of a thick steel cover provided confinement which aided path closure close to
the glass surface. Second, earlier studies (Zernow et al. 1975; Meyer 1987) showed that
reflected debris particles can disrupt a jet as it passes through a tubular opening. The
continuous jet in the second test was undoubtedly disrupted while passing through the 4.8-mm
diameter hole drilled through the steel cover, and the disruptions caused early interactions
between the jet and the closing penetration path. Protrusions and regions of intense
luminosity in Figure 12 are evidence of such interactions.
Photographic tests were also conducted to determine how a particulate jet interacts with
a target of soda-lime glass. Figure 16 shows a sequence
22
of photographs taken at 1–ps
E E ..
a:: w r-w ~ <{ -£:)
J:
~ a.:
6
4
°0
....... ...... ...... ..... 6,..
-..- .... _- .. ll,..
6. 25 mm PMMA COVER o DRILLED STEEL COVER
234
TIME , !-,-5
5
Figure 14. Path Diameter as a Function of Time (Continuous Jets).
6
arrives at the transition point where the target resistance increases. This jet element reached
the location of diameter measurements approximately 2.3 I1s after the tip. This time is in
general agreement with the 2-3 J..LS time at which the curves begin to deviate in Figure 14.
Two factors probably contributed to features of the penetration path in Figure 14. First,
the presence of a thick steel cover provided confinement which aided path closure close to
the glass surface. Second, earlier studies (Zernow et al. 1975; Meyer 1987) showed that
reflected debris particles can disrupt a jet as it passes through a tubular opening. The
continuous jet in the second test was undoubtedly disrupted while passing through the 4.8-mm
diameter hole drilled through the steel cover, and the disruptions caused early interactions
between the jet and the closing penetration path. Protrusions and regions of intense
luminosity in Figure 12 are evidence of such interactions.
Photographic tests were also conducted to determine how a particulated jet interacts with
a target of soda-lime glass. Figure 16 shows a sequence of photographs taken at 1-I1S
22
5(
4[
3(
2(
Ic
c
-Ic
-20
I
4/
/e//0
//
TRANSITION
R=7
/
J-2.3ps ,, MEASUREMENT OF
/
PATH DIAMETER
//’
A SODA-LIME GLASS\\
,.
/
PMMA (DRILLED TOADMIT THE JET)
,’
/
1 1 I 1 1nI. —
4 10 12
TIME , @
Figure 15. Penetration-Time Curves From Fiqure 13, Includinq a Path for the Jet ElementThat Arrives at the Transition Point.
23
50
40
E 30 E
8 20 r-« 0:: r- 10 w Z w a...
o
-10
-20
o
/
2
'" '" '"
'" '" '"
..... ..... -'" '" '"
TRANSITION~ '" " ~R=40
, ,
23ILS~MEASUREMENT OF . j.' PATH DIAMETER
" SODA- LIME GLASS
PMMA
4 6 8 TIME, fLS
STEEL (DRILLED TO
ADMIT THE JET)
10 12
Figure 15. Penetration-Time Curves From Figure 13, Including a Path for the Jet Element That Arrives at the Transition Point.
23
ll..
-(/) Q)
f--Q) --, "0 Q)
Iii :::> u t ell [L
ell
D c 0
~ ~
w a; c Q) [L
~
ell f-(/) (/) ell
c:?
t Q)
E :.::; , ell "0 0
Cf)
ell
<{ Cl 0 (/) .t::
I ell ~
II.~ ,-1i., .';'. ." • I f • . , -_.
i 0 -0 .t:: [L
E E <D 0 1
1 Q) ~
:::> Cl u:::
t
24
intervals during penetration by a particulate jet, The basic features are similar to those
observed with a continuous jet in Figure 10. Photographs show the boundary of the
penetration path, the permanently densified volume surrounding the penetration path, the
trailing fracture, and the fracture initiated at a bonded interface between glass plates.
However, these photographs show an undulating penetration path which opens and partially
closes with the impact of each successive jet particle. Intense self-luminosity is associated
with each impact. Reopening of the penetration path after partial closure is evident at the
neck region, which is indicated by arrows in Frames E and F. Path diameters were measured
both at the neck region and at the maximum which is indicated by arrows in Frame D.
Diameters at both locations are plotted against time in Figure 17. At the neck location,
reopening of the penetration path begins approximately 3.3 VS after the initial opening. This
reopening is attributed to the interaction with a jet particle as it passes the location of the
measurement in Frame F.
Figure 18 shows penetration-time data for the test pictured in Figure 16. As in the case of
a continuous jet, the initial part of penetration into soda-lime glass is described by the model
using an assigned target resistance of 7 GPa. At 16.6 VS, the final datum point is displaced
significantly below the extrapolated path for R = 7 GPa, providing minimal evidence of an
increase in target resistance. The jet element arriving at the apparent transition point passes
the neck location 3.1 VS after the penetration front, in close agreement with the reopening time
in Figure 17. This agreement increases confidence in the final datum point of Figure 18. With
the
the
highly symmetrical penetration path in Figure 16, reopening at the neck region is clearly
first evidence of an interaction with jet elements behind the penetration front.
The penetration pictured in Figure 19 was obtained with a test configuration nearly
identical to the one for the preceding test. However, this second test with a particulate jet
used only front lighting. Without back lighting, the permanently densified region cannot be
seen. In this test, the penetration path lacks the symmetry observed in the preceding test.
There are numerous protrusions and regions of intense self-luminosity that indicate a strong
interaction between the target and jet elements behind the penetration front. This different
behavior is attributed to round-to-round variations of the shaped charge. The penetration-time
data for this test are plotted in Figure 20. As in preceding tests with soda-lime glass, the first
25
intervals during penetration by a particulated jet. The basic features are similar to those
observed with a continuous jet in Figure 10. Photographs show the boundary of the
penetration path, the permanently densified volume surrounding the penetration path, the
trailing fracture, and the fracture initiated at a bonded interface between glass plates.
However, these photographs show an undulating penetration path which opens and partially
closes with the impact of each successive jet particle. Intense self-luminosity is associated
with each impact. Reopening of the penetration path after partial closure is evident at the
neck region, which is indicated by arrows in Frames E and F. Path diameters were measured
both at the neck region and at the maximum which is indicated by arrows in Frame D.
Diameters at both locations are plotted against time in Figure 17. At the neck location,
reopening of the penetration path begins approximately 3.3 IlS after the initial opening. This
reopening is attributed to the interaction with a jet particle as it passes the location of the
measurement in Frame F.
Figure 18 shows penetration-time data for the test pictured in Figure 16. As in the case of
a continuous jet, the initial part of penetration into soda-lime glass is described by the model
using an assigned target resistance of 7 GPa. At 16.6 Ils, the final datum pOint is displaced
significantly below the extrapolated path for A = 7 GPa, providing minimal evidence of an
increase in target resistance. The jet element arriving at the apparent transition pOint passes
the neck location 3.1 Ils after the penetration front, in close agreement with the reopening time
in Figure 17. This agreement increases confidence in the final datum point of Figure 18. With
the highly symmetrical penetration path in Figure 16, reopening at the neck region is clearly
the first evidence of an interaction with jet elements behind the penetration front.
The penetration pictured in Figure 19 was obtained with a test configuration nearly
identical to the one for the preceding test. However, this second test with a particulated jet
used only front lighting. Without back lighting, the permanently densified region cannot be
seen. In this test, the penetration path lacks the symmetry observed in the preceding test.
There are numerous protrusions and regions of intense self-luminosity that indicate a strong
interaction between the target and jet elements behind the penetration front. This different
behavior is attributed to round-to-round variations of the shaped charge. The penetration-time
data for this test are plotted in Figure 20. As in preceding tests with soda-lime glass, the first
25
1 I I I 1 I
6 -
/“ o-\~..0---”
A MAXIMUM LOCATION
o MINIMUM (NECK) LOCATION
o! 1 1 I 1 I 1 Iu
Figure 17.
I 2 3 4 5 6
TIME , ~S
Path Diameter as a Function of Time (Particulate Jet}.
part of penetration is described by the model using a target resistance of 7 GPa. However,
after approximately 9 VS of penetration into the glass, there is a pronounced deviation, and
later data can be described only by assigning a target resistance of 80 GPa. This large
increase in resistance must follow directly from the strong photographic evidence of jet-target
interactions behind the penetration front.
Photographs from a third test with a particulate jet are shown in Figure 21. Only back
lighting was used for this test. Increases in the index of refraction within permanently
densified glass, as shown by measurements of Arndt, Hornemann, and Muller (1971), cause
strong refraction of the back light and obscure detail behind the penetration front. Without
multiple shock waves, visible in the original photographs, it would not be obvious that
penetration was by a particulate jet. Refraction also obscures features of the penetration
path that provide evidence of target interactions with jet elements behind the penetration front.
However, the penetration-time data from this test, shown in Figure 22, clearly indicate that
such interactions must have occurred. The initial part of penetration into soda-lime glass is
again described by the model with R = 7 GPa. However, the point at 13.7 ~s (9.3 ps into the
26
~ 6 .. a:: w t--W ~ « -Cl
::r: t--~ 00
A MAXIMUM LOCATION o MINIMUM (NECK) LOCATION
234
TIME, fLs
5
Figure 17. Path Diameter as a Function of Time (Particulated Jet).
6
part of penetration is described by the model using a target resistance of 7 GPa. However,
after approximately 9 Ils of penetration into the glass, there is a pronounced deviation, and
later data can be described only by assigning a target resistance of 80 GPa. This large
increase in resistance must follow directly from the strong photographic evidence of jet-target
interactions behind the penetration front.
Photographs from a third test with a particulated jet are shown in Figure 21. Only back
lighting was used for this test. Increases in the index of refraction within permanently
densified glass, as shown by measurements of Arndt, Hornemann, and Muller (1971), cause
strong refraction of the back light and obscure detail behind the penetration front. Without
multiple shock waves, visible in the original photographs, it would not be obvious that
penetration was by a particulated jet. Refraction also obscures features of the penetration
path that provide evidence of target interactions with jet elements behind the penetration front.
However, the penetration-time data from this test, shown in Figure 22, clearly indicate that
such interactions must have occurred. The initial part of penetration into soda-lime glass is
again described by the model with R = 7 GPa. However, the point at 13.7 IlS (9.3 IlS into the
26
II
I1
II
I
n
m,
ml
Il’.
I
8I,II
4II
;i
..
*
I*
\●
✎
✼✎
✍
t-
UJU
J‘
NO
llVH
13N3d
27
80
70
60
E E
.. 50
z 0 I-- 40 « a:::
I\) I--....., W
Z 30 w a..
20
10
------
.'
j /
5
.'
/ .' /
/
10
TIME , fLS
15
SLG-3
. _.' 0
SLG-2 --------
SLG-I
PMMA
Figure 18. Penetration-Time Data for the Jet Penetration Shown in Figure 16.
20
l r w
28
(\J
en Q)
I-
m -, "0 Q)
~ :::l ()
t ro
Cl. ro
.0 c 0 ~ ro ~ m c Q)
Cl.
VJ VJ ro a Q)
E ::::; cb "0 o (/)
o o .c Cl.
J
1
70
10
5 10
TIME, fLs 15
Figure 20. Penetration-Time Data for the Jet Penetration Shown in Figure 19.
20
~
co I-III III CO
i3 Q)
E :::i cb "0 0 (f)
CO -0 III £:
CO ~
0 -0 £: a. "0 Q)
E :::i
f , -'" (.) E CO E (]) 0
i ~
C\J Q) ~
:J Ol
IT:
30
—
lulu‘
NO
llVU
13N3de.> .....
80
E E SLG-2 ..
.. 50 ~.. ._--~ISODAMP-I z
0 I-<{ 0:: l-W Z w a..
40
30 SLG-I PMMA
20
°0~----------~5~------------10L-------------IL5------------~20
TIME, fLs
Figure 22. Penetration-Time Data for the Jet Penetration Shown in Figure 21.
glass) has deviated from the initial path, and over the next 4 p.s the target resistance
increases to 70 GPa. The presence of Isodamp between the glass plates in this test did not
obviously influence the resistance to penetration, but it apparently delayed interface failure to
provide an additional 2 WSfor observations.
Monolithic soda-lime glass, without ferric-ion impurity, was used for the last photographic
test to be reported. Consecutive frames from this fourth test with a particulate jet are shown
in Figure 23. Strong interactions are indicated by the extremely irregular profile of the
penetration path, and irregularities tend to mask the particle nature of penetration. Periodic
emissions of light are the strongest evidence of particle impacts. Although this glass was
monolithic and offered no interfaces where fracture could be initiated, it did contain many
small bubbles which served as failure sites. Failure was not initiated by the impact shock, but
instead it was observed to occur when a bubble encountered the boundary of permanently
densified glass. Failure at bubbles occurs in Frame C, forward of the penetration path, and in
Frames D–F, where failure sites developed at both the left and right of the penetration path.
Penetration-time data for the test with monolithic soda-lime glass are shown in Figure 24.
The initial part of penetration into the glass is described by the model with R = 8 GPa. This
value is higher than the initial resistance in soda-lime plate used in other tests. The velocity
of trailing fracture was also higher (2,260 m/s, compared to 1,960 m/s for soda-lime plate). In
this test, the target resistance deviated to higher values after only 6 w of penetration into the
glass. However, the higher values of target resistance were consistent with values
determined in tests with soda-lime plate. Failure at bubble sites may have altered the closure
rate in this monolithic glass, causing an early interaction with jet elements behind the
penetration front. Resistance values in other tests with fused quartz and soda-lime plate
never increased earlier than 9 N after the onset of penetration into the glass. Based on this
consistency, it is unlikely that a time as short as 6 ps would have resulted from round-to-round
variation of the shaped charge.
2.5 Examination of Recovered Glass Tarqets. Radiographic targets that contained fused
quartz were recovered and examined. Qualitative visual examinations could not readily
distinguish these targets from recovered targets that contained borosilicate or soda-lime
glasses. Figure 25 shows a fused quartz target that was sectioned to expose the entire
32
glass) has deviated from the initial path, and over the next 4 J.1S the target resistance
increases to 70 GPa. The presence of Isodamp between the glass plates in this test did not
obviously influence the resistance to penetration, but it apparently delayed interface failure to
provide an additional 2 J.1s for observations.
Monolithic soda-lime glass, without ferric-ion impurity, was used for the last photographic
test to be reported. Consecutive frames from this fourth test with a particulated jet are shown
in Figure 23. Strong interactions are indicated by the extremely irregular profile of the
penetration path, and irregularities tend to mask the particle nature of penetration. Periodic
emissions of light are the strongest evidence of particle impacts. Although this glass was
monolithic and offered no interfaces where fracture could be initiated, it did contain many
small bubbles which served as failure sites. Failure was not initiated by the impact shock, but
instead it was observed to occur when a bubble encountered the boundary of permanently
densified glass. Failure at bubbles occurs in Frame C, forward of the penetration path, and in
Frames D-F, where failure sites developed at both the left and right of the penetration path.
Penetration-time data for the test with monolithic soda-lime glass are shown in Figure 24.
The initial part of penetration into the glass is described by the model with R = 8 GPa. This
value is higher than the initial resistance in soda-lime plate used in other tests. The velocity
of trailing fracture was also higher (2,260 mis, compared to 1,960 mls for soda-lime plate). In
this test, the target resistance deviated to higher values after only 6 J.1S of penetration into the
glass. However, the higher values of target resistance were consistent with values
determined in tests with soda-lime plate. Failure at bubble sites may have altered the closure
rate in this monolithic glass, causing an early interaction with jet elements behind the
penetration front. Resistance values in other tests with fused quartz and soda-lime plate
never increased earlier than 9 J.1S after the onset of penetration into the glass. Based on this
consistency, it is unlikely that a time as short as 6 J.1S would have resulted from round-to-round
variation of the shaped charge.
2.5 Examination of Recovered Glass Targets. Radiographic targets that contained fused
quartz were recovered and examined. Qualitative visual examinations could not readily
distinguish these targets from recovered targets that contained borosilicate or soda-lime
glasses. Figure 25 shows a fused quartz target that was sectioned to expose the entire
32
v -oo Cl> I-
u -Cl> --, "0 Cl> -.!!! :::J 0
"" ~ cu Il.. cu
.0 c: a "" CU ~
Q5 c: Cl> Il..
<II w
~
cu I-oo oo cu (5 Cl> E ::J , CU "0 a (J)
.2 ~
Cl "" "0 c: a
f :::2; cu -E a
E a
oo ~
1 cu ~
a -a ~
Il..
C') C\I
Cl> ~
:::J OJ u:
33
.
I10
\r=II
rI
II
1
\
\
m..‘\
)$:\\.\‘.:.\..‘.;...
J&
-11
Inma‘.
\.\\
,\
\.
11
*
11
1I
o0
00
0o
_b
am
em
N0
3...—1-
*“ml
Ulw
bN
OllV
H13N
3d—
34
60
E 50 E
z 40 0
~ w a:: ~ J- 30 w
z W 0-
20
~.
, ".,
,
, , , ,
.,,/-~FRACTURE / V=2260m/s
, ,-'
, ,
MONOLITHIC SLG ---O"'~-- ---------- ----- --
5 10
TIME ~ fLs
PMMA
15
Figure 24. Penetration-Time Data for the Jet Penetration Shown in Figure 23.
20
Figure 25. Fused Quartz Target Sectioned to Expose the Penetration Path Filled With Red Glass.
35
penetration path. Thepath incompletely filled with aporous, opaque, red copper-glass. In
the future, this material will bereferred tosimply as "red glass.'' Astatic x-ray of a recovered
target is shown in Figure 26A, and it reveals that the red glass mntains suspended copper
spheres with diameters up to approximately 2 mm. An SEM micrograph of the red glass is
shown in Figure 266. The large copper sphere at the left in the micrograph has a diameter of
80 ~m, while the smallest spheres approach a diameter of 1 Vm. When a sample of red glass
was examined at the Battelle Pacific Northwest Laboratories, it was concluded that the glass
contained approximately 57. reacted/dissolved copper in addition to suspended copper
spheres. Battelle cited a book by Weyl (1951) and noted the similarity to hematinone, which
is an opaque red glass (glaze) containing suspended copper particles in the submicron range.
Red glass in the penetration path is very fluid just after it is formed and it frequently flows
out of the target. Figure 27 shows red glass which was recovered after it flowed from the
back of a fused quartz target that was perforated by the jet. Although a target may not be
perforated, much of the red glass can also be forced out through the entrance hole if the slug
is allowed to enter. This behavior in a borosilicate glass target is shown in Figure 28.
Figures 28A and 28B show the void produced when the slug displaced red glass from the
penetration path; Figure 28C shows part of the displaced red glass in a trap at the front of the
target; and, Figure 28D shows slug material and red glass near the end of penetration. Radial
cracks in Figure 28D are typical of failure near the end of penetration in targets of both glass
and crystalline quartz. In Figure 28A, it may be noted that temperatures in the penetration
path were high enough to remelt a significant thickness of pulverized glass around the
penetration path (M identifies an area of remelted glass).
The porosity of red glass in the penetration path is tentatively attributed to localized
heating that produces partial vaporization of the jet metal. Cavities in the red glass are
commonly coated with small copper spheres and it is hypothesized that this deposit resulted
from the condensation of copper vapor that initially filled the cavity. It was also observed that
little porosity is produced when glass is penetrated by a steel jet, which should vaporize at a
higher temperature. Penetration paths produced in glass by copper and steel jets are shown
in Figures 29A and 29B, respectively. One glass target penetrated by an aluminum jet was
examined, but the result was ambiguous. As shown in Figures 29C and 29D, material was
ejected from the penetration path and deposited on an overhead plate. Vaporization of the
36
penetration path. The path is completely filled with a porous. opaque. red copper-glass. In
the future. this material will be referred to simply as "red glass." A static x-ray of a recovered
target is shown in Figure 26A. and it reveals that the red glass contains suspended copper
spheres with diameters up to approximately 2 mm. An SEM micrograph of the red glass is
shown in Figure 26B. The large copper sphere at the left in the micrograph has a diameter of
80 ~m. while the smallest spheres approach a diameter of 1 jlm. When a sample of red glass
was examined at the Battelle Pacific Northwest Laboratories. it was concluded that the glass
contained approximately 5% reacted/dissolved copper in addition to suspended copper
spheres. Battelle cited a book by Weyl (1951) and noted the similarity to hematinone. which
is an opaque red glass (glaze) containing suspended copper particles in the submicron range.
Red glass in the penetration path is very fluid just after it is formed and it frequently flows
out of the target. Figure 27 shows red glass which was recovered after it flowed from the
back of a fused quartz target that was perforated by the jet. Although a target may not be
perforated. much of the red glass can also be forced out through the entrance hole if the slug
is allowed to enter. This behavior in a borosilicate glass target is shown in Figure 28.
Figures 28A and 28B show the void produced when the slug displaced red glass from the
penetration path; Figure 28C shows part of the displaced red glass in a trap at the front of the
target; and. Figure 280 shows slug material and red glass near the end of penetration. Radial
cracks in Figure 280 are typical of failure near the end of penetration in targets of both glass
and crystalline quartz. In Figure 28A. it may be noted that temperatures in the penetration
path were high enough to remelt a significant thickness of pulverized glass around the
penetration path (M identifies an area of remelted glass).
The porosity of red glass in the penetration path is tentatively attributed to localized
heating that produces partial vaporization of the jet metal. Cavities in the red glass are
commonly coated with small copper spheres and it is hypothesized that this deposit resulted
from the condensation of copper vapor that initially filled the cavity. It was also observed that
little porosity is produced when glass is penetrated by a steel jet. which should vaporize at a
higher temperature. Penetration paths produced in glass by copper and steel jets are shown
in Figures 29A and 29B. respectively. One glass target penetrated by an aluminum jet was
examined, but the result was ambiguous. As shown in Figures 29C and 290. material was
ejected from the penetration path and deposited on an overhead plate. Vaporization of the
36
c.> .....
., .'. · · • _ _ , "J I , .. • • . .-.""'
" . ...... ~. :~'~ I
"
, , . ~
•• •• HOmm1
• A
Figure 26. (A) Static Radiograph of the Penetration Path in Fused Quartz; (8) SEM Micrograph of Red Glass From the Penetration Path in Fused Quartz.
IIOmm I
Figure 27. Red Glass That Flowed From the Back of a Perforated Fused Quartz Target.
38
t-- 1--- 5mm----I
M
..... - .. 1---5mm----I A B
D
HOmm-i 1-5mm-l
Figure 28. Recovered Target of Borosilicate Glass Showing Red Glass Displaced When the Slug Entered the Target.
39
.j:. o
I4-lmm
• ; -
"
A B Imm
c
-t I-Imm
Figure 29. Glass Targets Penetrated by (A) a Copper Jet, (8) a Steel Jet, and (C) an Aluminum Jet; (D) is a Deposit of Material Ejected From the Penetration Path in (C) .
aluminum jet could have contributed to the ejection, but the penetration model indicated that
aluminum erosion products should travel out of the target at velocities from 700 to 2,500 mls
without a contribution from vaporization.
Evidence indicates that there is a significant interaction between the jet and red glass
which fills the penetration path. Figure 26A, for example, shows a great amount of jet material
suspended as spheres in the red glass. Additional evidence is provided by Figure 30, which
shows a section of the penetration path produced in fused quartz by a small and relatively
slow copper jet. In this test, red glass flowed into spaces between jet particles, with the
exception of a channel that persisted between the two large central particles. These two
particles are tapered, which gives evidence of erosion as they penetrated the red glass.
Interaction with the red glass was strong enough to arrest the forward motion of the entire
sequence of jet particles. The high melt viscosity of fused quartz was probably a factor in the
resistance to particle penetration in this test.
1< 5mm .. I
PENETRATION)
Figure 30. Tapered Jet Particles in Red Glass.
41
2.6 Formation and Role of Red Glass. A recent study by Meade and Jeanloz (1988) was
examined for its possible relationship to behavior during jet penetration into glasses. These
investigators used a Mao-Bell diamond cell to conduct static high-pressure measurements on
a sample of fused quartz mixed with three weight percent ruby of similar particle size. Using
ruby fluorescence, they determined both the average pressure and the pressure gradient
across the sample, which together with the sample thickness provided an approximate
evaluation of the maximum shear stress supported by the sample at pressures between
8.6 and 81 GPa. For convenience, the data of Meade and Jeanloz are plotted in Figure 31.
At an average pressure of 8.6 GPa, they concluded that fused quartz flows plastically, with a
maximum shear stress less than 1 GPa. This conclusion is consistent with the results of
Cagnoux (1981) who concluded from uniaxial strain experiments that a borosilicate glass
exhibited plastic response above the dynamic yield stress. Above 8.6 GPa, the maximum
shear stress measured by Meade and Jeanloz increased. At 26.9 GPa, it attained a value
close to 4.3 GPa, which is approximately the value reported by Proctor, Whitney, and Johnson
(1967) at atmospheric pressure where fused quartz undergoes brittle failure. This result is
consistent with the result by Anan’in, et al. (1974a), who concluded from shock-wave
experiments that fused quartz fails into microblocks separated by interlayers of melt.
Similarly, Kanel, Molodets, and Dremin (1976) concluded from shock wave experiments that
K-8 glass (a borosilicate composition) fails into particles with the subsequent formation of
fused interlayers. Above a pressure of 26.9 GPa, the data of Meade and Jeanloz show that
the maximum shear stress decreases to approximately 0.3 GPa at a pressure of 65 GPa.
Interface pressure during the initial part of jet penetration into fused quartz corresponds to
average pressures where Meade and Jeanloz reported the highest values of shear strength.
This suggests that brittle interface behavior occurs at the penetration front, with the possibility
that jet and target materials mix locally and rapidly produce the red glass. This possibility was
evaluated experimentally by using the technique of Franz and Lawrence (1987) to remove the
rear portion of a copper jet and penetrate a glass target with only a fraction of the jet length.
With a 17 mm length of jet, a visual examination of the recovered target detected only metallic
copper. With a 39 mm length of jet, red glass was clearly beginning to form and accumulate
along the penetration path. It was evident from these tests that red glass does not form
rapidly as a result of brittle behavior at the penetration front. Instead, it tends to form
gradually and accumulate throughout an extended interval during penetration by a copper jet.
42
2.6 Formation and Role of Red Glass. A recent study by Meade and Jeanloz (1988) was
examined for its possible relationship to behavior during jet penetration into glasses. These
investigators used a Mao-Bell diamond cell to conduct static high-pressure measurements on
a sample of fused quartz mixed with three weight percent ruby of similar particle size. Using
ruby fluorescence, they determined both the average pressure and the pressure gradient
across the sample, which together with the sample thickness provided an approximate
evaluation of the maximum shear stress supported by the sample at pressures between
8.6 and 81 GPa. For convenience, the data of Meade and Jeanloz are plotted in Figure 31.
At an average pressure of 8.6 GPa, they concluded that fused quartz flows plastically, with a
maximum shear stress less than 1 GPa. This conclusion is consistent with the results of
Cagnoux (1981) who concluded from uniaxial strain experiments that a borosilicate glass
exhibited plastic response above the dynamic yield stress. Above 8.6 GPa, the maximum
shear stress measured by Meade and Jeanloz increased. At 26.9 GPa, it attained a value
close to 4.3 GPa, which is approximately the value reported by Proctor, Whitney, and Johnson
(1967) at atmospheric pressure where fused quartz undergoes brittle failure. This result is
consistent with the result by Anan'in, et al. (1974a), who concluded from shock-wave
experiments that fused quartz fails into microblocks separated by interlayers of melt.
Similarly, Kanel, Molodets, and Dremin (1976) concluded from shock wave experiments that
K-8 glass (a borosilicate composition) fails into particles with the subsequent formation of
fused interlayers. Above a pressure of 26.9 GPa, the data of Meade and Jeanloz show that
the maximum shear stress decreases to approximately 0.3 GPa at a pressure of 65 GPa.
Interface pressure during the initial part of jet penetration into fused quartz corresponds to
average pressures where Meade and Jeanloz reported the highest values of shear strength.
This suggests that brittle interface behavior occurs at the penetration front, with the possibility
that jet and target materials mix locally and rapidly produce the red glass. This possibility was
evaluated experimentally by using the technique of Franz and Lawrence (1987) to remove the
rear portion of a copper jet and penetrate a glass target with only a fraction of the jet length.
With a 17 mm length of jet. a visual examination of the recovered target detected only metallic
copper. With a 39 mm length of jet, red glass was clearly beginning to form and accumulate
along the penetration path. It was evident from these tests that red glass does not form
rapidly as a result of brittle behavior at the penetration front. Instead, it tends to form
gradually and accumulate throughout an extended interval during penetration by a copper jet.
42
gm=a
●●
●O
\
o
●
✏
●
o/
@
\
●
●
o
43
o 5 MEADE 8& JEANLOZ (1988) a.
(9 .. ® o RECOMPRESSION en '0 en w 0:: t-en 0::: • • ~ <! t.) • W I en 0
• ~ • • • :J
/ ~ 0
X <! ~ •
00 20 40 60 80 AVERAGE PRESSURE , GPo
Figure 31. Data of Meade and Jeanloz.
However, the rate of formation may depend on characteristics of the jefftarget interaction.
Figures 20, 22, and 24 suggest that a glass target may interact more strongly with a jet
broken into discrete particles, and it should be noted that the condition of the jet was different
in the two tests with a short jet length. With a 17 mm length, 75% of the penetration was by a
continuous jet. With a 39 mm length, 99°/0of the penetration was by discrete particles. The
particulate condition of the longer length may have been a factor in the formation of red
glass detected in the target recovered form that experiment.
The photographs in Figures 10 and 16 show fine longitudinal detail which suggests the
termination of radial cracks at the boundary of the penetration path. The appearance was
confirmed when boundary layers were recovered and examined. This observation suggests
that opening and closure are accompanied by brittle failure at the cavity wall, producing glass
particles which mix with material eroded from the jet. The Modified Bernoulli Penetration
Model indicates that erosion products from the jet should flow into the target at a relatively
high velocity. In Figure 3, lead-glass tracers show that target material in the penetration path
also moves rapidly into the target, implying that it is swept along in the flow of erosion
products. The uniform distribution of tracer material in the penetration path implies mixing and
an opportunity for target material to interact with the side of the jet. This interaction is
confirmed by the abrupt decrease in penetration velocity shortly after closure. Red glass
probably is just a by-product of the initial interaction. However, as it accumulates, it must
become a major influence of the penetration. Judging by the presence of large jet particles
arrested in the red glass, it is highly resistant to penetration. The full role of red glass is not
understood at this time, but possible influences are considered in the final discussion.
2.7 Test for Permanent Densification. One recovery experiment was conducted to verify
that permanent densification occurs during jet penetration into fused quartz. The configuration
of this experiment is shown in Figure 32. The front surface of the fused quartz was
unconfined and surrounded by a trap with a small hole to admit the jet. The shaped charge
for this test produced a relatively massive and slow moving slug that sealed the hole into the
trap. The density of particles recovered from the trap was measured by a procedure similar to
the one reported by Wackerle (1962). Dimethyl formamide was floated over methylene iodide
in a square cuvette. Slight mixing and diffusion of the two liquids produced a column of
varying density which was calibrated by introducing glass particles with different known
44
However. the rate of formation may depend on characteristics of the jet/target interaction.
Figures 20. 22. and 24 suggest that a glass target may interact more strongly with a jet
broken into discrete particles. and it should be noted that the condition of the jet was different
in the two tests with a short jet length. With a 17 mm length. 75% of the penetration was by a
continuous jet. With a 39 mm length. 99% of the penetration was by discrete particles. The
particulated condition of the longer length may have been a factor in the formation of red
glass detected in the target recovered form that experiment.
The photographs in Figures 10 and 16 show fine longitudinal detail which suggests the
termination of radial cracks at the boundary of the penetration path. The appearance was
confirmed when boundary layers were recovered and examined. This observation suggests
that opening and closure are accompanied by brittle failure at the cavity wall. producing glass
particles which mix with material eroded from the jet. The Modified Bernoulli Penetration
Model indicates that erosion products from the jet should flow into the target at a relatively
high velocity. In Figure 3. lead-glass tracers show that target material in the penetration path
also moves rapidly into the target. implying that it is swept along in the flow of erosion
products. The uniform distribution of tracer material in the penetration path implies mixing and
an opportunity for target material to interact with the side of the jet. This interaction is
confirmed by the abrupt decrease in penetration velocity shortly after closure. Red glass
probably is just a by-product of the initial interaction. However. as it accumulates. it must
become a major influence of the penetration. Judging by the presence of large jet particles
arrested in the red glass. it is highly resistant to penetration. The full role of red glass is not
understood at this time. but possible influences are considered in the final discussion.
2.7 Test for Permanent Densification. One recovery experiment was conducted to verify
that permanent densification occurs during jet penetration into fused quartz. The configuration
of this experiment is shown in Figure 32. The front surface of the fused quartz was
unconfined and surrounded by a trap with a small hole to admit the jet. The shaped charge
for this test produced a relatively massive and slow moving slug that sealed the hole into the
trap. The density of particles recovered from the trap was measured by a procedure similar to
the one reported by Wackerle (1962). Dimethyl formamide was floated over methylene iodide
in a square cuvette. Slight mixing and diffusion of the two liquids produced a column of
varying density which was calibrated by introduCing glass particles with different known
44
— TRAP4
FUSED QUARTZ 7— /
n ‘MflflflM4H-J STEEL
Figure 32. Tamet Configuration Used to Recover Permanently Densified Fused Quartz.
densities. Recovered particles were also introduced into the column, and particle locations
were measured by a traveling microscope at a magnification of 60x. This magnification
allowed a careful inspection of each recovered particle to verify that it was not contaminated
with copper. Many uncontaminated particles from the trap were found to be permanently
densified, and the maximum densification was approximately 10YO.
The maximum densification of recovered particles is in close agreement with the results of
Arndt, Hornemann, and Muller (1971) who found that maximum permanent densification of
10.37!/. occurs at a shock stress of 13.5 GPa. However, Cohen and Roy (1965) measured a
maximum permanent densification of 19.1‘?4.when fused quartz was statically compressed to
15.0 GPa at room temperature. Therefore, the maximum densification during shock loading
probably exceeds 10.377., but the residual temperature anneals and reduces the permanent
densification before glass specimens can be recovered for measurements. Highly densified
particles were not found in target material surrounding the penetration path in fused quartz.
However, annealing at 1,173 K causes almost complete recovery in a few minutes (Arndt,
Hornemann, and Muller 1971), and in Figure 28A, remelting around the penetration path in
45
STEEL
Figure 32. Target Configuration Used to Recover Permanently Densified Fused Quartz.
densities. Recovered particles were also introduced into the column, and particle locations
were measured by a traveling microscope at a magnification of 60x. This magnification
allowed a careful inspection of each recovered particle to verify that it was not contaminated
with copper. Many uncontaminated particles from the trap were found to be permanently
densified, and the maximum densification was approximately 10%.
The maximum densification of recovered particles is in close agreement with the results of
Arndt, Hornemann, and Muller (1971) who found that maximum permanent densification of
10.37% occurs at a shock stress of 13.5 GPa. However, Cohen and Roy (1965) measured a
maximum permanent densification of 19.1% when fused quartz was statically compressed to
15.0 GPa at room temperature. Therefore, the maximum densification during shock loading
probably exceeds 10.37%, but the residual temperature anneals and reduces the permanent
densification before glass specimens can be recovered for measurements. Highly densified
particles were not found in target material surrounding the penetration path in fused quartz.
However, annealing at 1,173 K causes almost complete recovery in a few minutes (Arndt,
Hornemann, and Muller 1971), and in Figure 28A, remelting around the penetration path in
45
borosilicate glass implies a probable temperature between 1,100 K and 1,500 K. In a fused
quartz target, where the diameter of the densified column is less than twice the diameter of
the penetration path, heat transfer from the penetration path should produce annealing and
explain the absence of particles with a high permanent densification.
2.8 Examination of Recovered Crystalline Quartz Tamets. The crystalline quartz target
shown in Figure 3B was recovered and examined. A static radiograph of the recovered core
is shown in Figure 33A. The slug was not prevented from entering the target and it
accumulated in the upper part of the penetration path. The forward flow of jet and tracer
material was found in the lower part of the target, with a massive accumulation at the end of
penetration. Cross sections from the lower part of the target are shown in Figures 33B–33D.
Here, the feathery appearance results from jet material which invaded small radial cracks in
the quartz. Cross sections B, C, and D indicate nearly complete closure of the penetration
path. There was no evidence that jet penetration into crystalline quartz was influenced by this
closure, and this suggests that closure resulted mainly from target material displaced at late
times. Factors contributing to this displacement could be the massive accumulation of
material at the end of penetration and the slug which was arrested in the preceding section of
the target. No red glass was detected in the crystalline quartz target shown in Figure 3B.
However, the presence of tantalum carbide may have either influenced the copper/quartz
interaction of obscured the presence of red glass. Other crystalline quartz targets were tested
either without tracers or with tracers of tantalum metal and were found to contain thin deposits
of red glass along the penetration path. This reveals only limited mixing and interaction of the
jet and target materials in crystalline quartz and indicates relatively conventional behavior, with
interaction only along the cavity wall.
3. SUMMARY AND FINAL DISCUSSION
Experimental studies of jet penetration into glass and crystalline quartz reveal differences
that should relate to the ability of these materials to resist penetration. The penetration paths
are different, and the jet and target materials interact differently. Permanent densification also
distinguishes the behavior of glass from that of crystalline quartz and may have a role in the
resistance of glass targets to jet penetration.
46
borosilicate glass implies a probable temperature between 1,100 K and 1,500 K. In a fused
quartz target, where the diameter of the densified column is less than twice the diameter of
the penetration path, heat transfer from the penetration path should produce annealing and
explain the absence of particles with a high permanent densification.
2.8 Examination of Recovered Crystalline Quartz Targets. The crystalline quartz target
shown in Figure 3B was recovered and examined. A static radiograph of the recovered core
is shown in Figure 33A. The slug was not prevented from entering the target and it
accumulated in the upper part of the penetration path. The forward flow of jet and tracer
material was found in the lower part of the target, with a massive accumulation at the end of
penetration. Cross sections from the lower part of the target are shown in Figures 33B-33D.
Here, the feathery appearance results from jet material which invaded small radial cracks in
the quartz. Cross sections B, C, and D indicate nearly complete closure of the penetration
path. There was no evidence that jet penetration into crystalline quartz was influenced by this
closure, and this suggests that closure resulted mainly from target material displaced at late
times. Factors contributing to this displacement could be the massive accumulation of
material at the end of penetration and the slug which was arrested in the preceding section of
the target. No red glass was detected in the crystalline quartz target shown in Figure 3B.
However, the presence of tantalum carbide may have either influenced the copper/quartz
interaction of obscured the presence of red glass. Other crystalline quartz targets were tested
either without tracers or with tracers of tantalum metal and were found to contain thin depOSits
of red glass along the penetration path. This reveals only limited mixing and interaction of the
jet and target materials in crystalline quartz and indicates relatively conventional behavior, with
interaction only along the cavity wall.
3. SUMMARY AND FINAL DISCUSSION
Experimental studies of jet penetration into glass and crystalline quartz reveal differences
that should relate to the ability of these materials to resist penetration. The penetration paths
are different, and the jet and target materials interact differently. Permanent densification also
distinguishes the behavior of glass from that of crystalline quartz and may have a role in the
resistance of glass targets to jet penetration.
46
I--.... -~--
A I-:Omm-l
B
c
HOmm-i
HOmm-l
I-IOmm-l
Figure 33. (A) Static Radiograph of the Crystalline Quartz Target; (8-0) Are Cross Sections of the Target in (A) Showing Cavity Closure.
47
The penetration behavior of crystalline quartz is relatively conventional. The jet is
surrounded by a cavity and there is only limited mixing of jet and target materials, as indicated
by thin deposits of red glass along the penetration path. A recovered target provided
evidence of cavity closure, but there was no substantial evidence that closure occurred early
in the penetration or that it influenced the penetration into crystalline quartz.
Photographic observations indicated less conventional behavior in glass targets. A small
copper jet produces a penetration path which opens to its maximum diameter in a few
microseconds and then closes rapidly after the penetration front passes. The boundary of
permanently densified glass shows only a slight necking associated with elastic recovery of
the surrounding target material. If back-lighted photographs were the only source of
information, then the strong refraction of back light by the permanently densified volume might
be mistaken for opacity associated with fracture. However, with front lighting, the target is
observed to remain transparent in to the boundary of the penetration path where the only
evidence of brittle fracture is detected. Unless bubbles are present, no brittle failure is
detected within the permanently densified volume or in the surrounding target until damage
propagates either from an interface or from the impacted surface. This suggests that initial
closure of the penetration path is caused by recovery from high pressures near the
penetration front and does not result from dilatancy associated with target failure into discrete
particles. Measurements of closure show that the inside diameter of the penetration path
approaches the diameter of the jet, producing an interaction which is detected by an abrupt
decrease in the penetration velocity (increase in resistance to penetration). Flash radiographs
show that the jet is disrupted in a glass target, and it is concluded that path closure is the
primary influence.
The boundary of the penetration path in glass exhibits features of brittle failure, and brittle
behavior both at peak interface pressures and after pressure release is consistent with data
presented in Figure 31. Brittle failure of target material at the boundary of the penetration
path is also consistent with the presence of glass particles in the penetration path. Initially,
the glass particles must be permanently densified as a result of high pressures experienced at
the penetration front. Glass particles accumulate in the penetration path where they interact
with the jet and its erosion products. This interaction causes melting of the glass particles and
both melting and vaporization of copper jet material. Melting produces a volume recovery of
48
The penetration behavior of crystalline quartz is relatively conventional. The jet is
surrounded by a cavity and there is only limited mixing of jet and target materials, as indicated
by thin deposits of red glass along the penetration path. A recovered target provided
evidence of cavity closure, but there was no substantial evidence that closure occurred early
in the penetration or that it influenced the penetration into crystalline quartz.
Photographic observations indicated less conventional behavior in glass targets. A small
copper jet produces a penetration path which opens to its maximum diameter in a few
microseconds and then closes rapidly after the penetration front passes. The boundary of
permanently densified glass shows only a slight necking associated with elastic recovery of
the surrounding target material. If back-lighted photographs were the only source of
information, then the strong refraction of back light by the permanently densified volume might
be mistaken for opacity associated with fracture. However, with front lighting, the target is
observed to remain transparent in to the boundary of the penetration path where the only
evidence of brittle fracture is detected. Unless bubbles are present, no brittle failure is
detected within the permanently densified volume or in the surrounding target until damage
propagates either from an interface or from the impacted surface. This suggests that initial
closure of the penetration path is caused by recovery from high pressures near the
penetration front and does not result from dilatancy associated with target failure into discrete
particles. Measurements of closure show that the inside diameter of the penetration path
approaches the diameter of the jet, producing an interaction which is detected by an abrupt
decrease in the penetration velocity (increase in resistance to penetration). Flash radiographs
show that the jet is disrupted in a glass target, and it is concluded that path closure is the
primary influence.
The boundary of the penetration path in glass exhibits features of brittle failure, and brittle
behavior both at peak interface pressures and after pressure release is consistent with data
presented in Figure 31. Brittle failure of target material at the boundary of the penetration
path is also consistent with the presence of glass particles in the penetration path. Initially,
the glass particles must be permanently densified as a result of high pressures experienced at
the penetration front. Glass particles accumulate in the penetration path where they interact
with the jet and its erosion products. This interaction causes melting of the glass particles and
both melting and vaporization of copper jet material. Melting produces a volume recovery of
48
the glass and, together with porosity, enables glass to fill the penetration path. The red color
gradually develops as copper becomes suspended and partially reacts with the glass.
Porosity in red glass is tentatively attributed to pockets of vaporized jet material which
eventually condenses to coat the surface of pores. Steel jets have been found to produce
relatively little porosity in glass that accumulates in the penetration path, and this is consistent
with a vaporization temperature higher than that of copper. The greater effectiveness of steel
jets against glass targets (Heine-Geldern 1954; Allison 1960) suggests that vaporization and
the resulting porosity have an influence on the jetitarget interaction.
Material flow in the penetration path is another potential influence on the jet. The
penetration model indicates that erosion products, in most cases, flow into glass targets at a
high rate. Tracer experiments indicate that local target material accompanies the flow of
erosion products. Material flow within an irregular penetration path, as shown in Figure 14,
may contribute to disruption of the jet. Layering dissimilar target materials should also
produce irregular penetration paths which may be disruptive, especially during oblique
penetration.
Although dilatancy associated with brittle failure is not the primary cause of path closure in
targets of soda-lime gas, it may make a secondary contribution. When failure occurred at
bubbles in a glass target, the early increase in target resistance may have resulted from a
contribution of dilatancy to path closure. Also, if dilatancy is able to bulge the front steel
confinement of glass targets (the “rebound effect” [Heine-Geldern 1954; Allison 1960]) it may
also contribute to jet disruption by opposing reopening of the penetration path which is shown
in Figures 14 and 17.
49
the glass and, together with porosity, enables glass to fill the penetration path. The red color
gradually develops as copper becomes suspended and partially reacts with the glass.
Porosity in red glass is tentatively attributed to pockets of vaporized jet material which
eventually condenses to coat the surface of pores. Steel jets have been found to produce
relatively little porosity in glass that accumulates in the penetration path, and this is consistent
with a vaporization temperature higher than that of copper. The greater effectiveness of steel
jets against glass targets (Heine-Geldern 1954; Allison 1960) suggests that vaporization and
the resulting porosity have an influence on the jeVtarget interaction.
Material flow in the penetration path is another potential influence on the jet. The
penetration model indicates that erosion products, in most cases, flow into glass targets at a
high rate. Tracer experiments indicate that local target material accompanies the flow of
erosion products. Material flow within an irregular penetration path, as shown in Figure 14,
may contribute to disruption of the jet. Layering dissimilar target materials should also
produce irregular penetration paths which may be disruptive, especially during oblique
penetration.
Although dilatancy associated with brittle failure is not the primary cause of path closure in
targets of soda-lime gas, it may make a secondary contribution. When failure occurred at
bubbles in a glass target, the early increase in target resistance may have resulted from a
contribution of dilatancy to path closure. Also, if dilatancy is able to bulge the front steel
confinement of glass targets (the "rebound effect" [Heine-Geldern 1954; Allison 1960]) it may
also contribute to jet disruption by opposing reopening of the penetration path which is shown
in Figures 14 and 17.
49
lNTEtNwONALLYLWT BUNK.
50
INTENTIONALLY LEFT BLANK.
50
4. REFERENCES
Allison, F. E. “Defeat of Shaped Charge Weapons.” Final report, Contract No.DA-36-061 -ORD-507 Carnegie Institute of Technology, Pittsburgh, PA, April 1960.
Anan’in, A. V., O. N. Breusov, A. N. Dremin, S. V. Pershin, A. 1.Rogacheva, and V. F, Tatsii.“Action of Shock Waves in Silicon Dioxide Il. Quartz Glass.” Fizika Goreniva i Vzryva,vol. 10, pp. 578–583, July–August 1974a.
Anan’in, A. V., O. N. Breusov, A. N. Dremin, S. V. Pershin, and V. F. Tatsii. “The Effect ofShock Waves on Silicon Dioxide 1. Quartz.” Fizika Goreniya i Vzryva, vol. 10,pp. 426436, May-June 1974b.
Arndt, J., U. Hornemann, and W. F. Muller. “Shock-Wave Densification of Silica Glass.”Phvsics and Chemistrv of Glasses, vol. 12, pp. 1–7, February 1971.
Bridgman, P. W., and 1.Simon. “Effects of Very High Pressure on Glass.” Journal of Applied
=$ vol. 24, pp. 405-413, April 1953.
Cagnoux, J. “Shock-Wave Compression of a Borosilicate Glass Up to 170 kbar.” Paperpresented at the APS Conference, Stanford Research institute, Menlo Park, CA, June 1981.
Cohen, H. M., and R. Roy. “Densification of Glass at Very High Pressures.” Physics andChemistry of Glasses, vol. 6, pp. 149-161, October 1965.
Franz, R. E., and W. Lawrence. “Design of a System for Cutting Shaped Charge Jets forPenetration Experiments.” BRL-MR-3608, U.S. Army Ballistic Research Laboratory,Aberdeen Proving Ground, MD, June 1987.
Gibbons, R. V., and T. J. Ahrens. “Shock Metamorphism of Silicate Glasses.” Journal ofGeophysical Research, vol. 76, pp. 5489–5497, August 1971.
Hauver, G. E., and K. A. Benson. “Asymmetry of Detonation Waves Emerging From M36 andM36-M18 Initiated Tetryl Pellets.” BRL-MR-893, U.S. Army Ballistic Research Laboratory,Aberdeen Proving Ground, MD, May 1955.
Heine-Geldern, R. V. “Critical Review of Shaped Charge Information: Chapter IX. Defeat ofShaped Charge Weapons.” BRL Report 905, U.S. Army Ballistic Research Laboratory,Aberdeen Proving Ground, MD, May 1954.
Kanel, G. l., A. M. Molodets, and A. N. Dremin. “Investigation of Singularities of Glass StrainUnder Intense Compression Waves.” Fizika Goreniya i Vzryva, vol. 13, pp. 906-912,November–December 1976.
Meade, E., and R. Jeanloz. “Effect of Coordination Change on the Strength of AmorphousSilica.” Science, vol. 241, pp. 1072–1074, 26 August 1988.
51
4. REFERENCES
Allison, F. E. "Defeat of Shaped Charge Weapons." Final report, Contract No. DA-36-061-0RD-507 Carnegie Institute of Technology, Pittsburgh, PA, April 1960.
Anan'in, A. V., O. N. Breusov, A. N. Dremin, S. V. Pershin, A. I. Rogacheva, and V. F. Tatsii. "Action of Shock Waves in Silicon Dioxide II. Quartz Glass." Fizika Goreniya i Vzryva, vol. 10, pp. 578-583, July-August 1974a.
Anan'in, A. V., O. N. Breusov, A. N. Dremin, S. V. Pershin, and V. F. Tatsii. "The Effect of Shock Waves on Silicon Dioxide I. Quartz." Fizika Goreniya i Vzryva, vol. 10, pp. 426-436, May-June 1974b.
Arndt, J., U. Hornemann, and W. F. Muller. "Shock-Wave Densification of Silica Glass." Physics and Chemistry of Glasses, vol. 12, pp. 1-7, February 1971.
Bridgman, P. W., and I. Simon. "Effects of Very High Pressure on Glass." Journal of Applied Physics, vol. 24, pp. 405-413, April 1953.
Cagnoux, J. "Shock-Wave Compression of a Borosilicate Glass Up to 170 kbar." Paper presented at the APS Conference, Stanford Research Institute, Menlo Park, CA, June 1981.
Cohen, H. M., and R. Roy. "Densification of Glass at Very High Pressures." Physics and Chemistry of Glasses, vol. 6, pp. 149-161, October 1965.
Franz, R. E., and W. Lawrence. "Design of a System for Cutting Shaped Charge Jets for Penetration Experiments." BRL-MR-3608, U.S. Army Ballistic Research Laboratory, Aberdeen Proving Ground, MD, June 1987.
Gibbons, R. V., and T. J. Ahrens. "Shock Metamorphism of Silicate Glasses." Journal of Geophysical Research, vol. 76, pp. 5489-5497, August 1971.
Hauver, G. E., and K. A. Benson. "Asymmetry of Detonation Waves Emerging From M36 and M36-M18 Initiated Tetryl Pellets." BRL-MR-893, U.S. Army Ballistic Research Laboratory, Aberdeen Proving Ground, MD, May 1955.
Heine-Geldern, R. V. "Critical Review of Shaped Charge Information: Chapter IX. Defeat of Shaped Charge Weapons." BRL Report 905, U.S. Army Ballistic Research L.aboratory, Aberdeen Proving Ground, MD, May 1954.
Kanel, G. I., A. M. Molodets, and A. N. Dremin. "Investigation of Singularities of Glass Strain Under Intense Compression Waves." Fizika Goreniya i Vzryva, vol. 13, pp. ~106-912, November-December 1976.
Meade, E., and R. Jeanloz. "Effect of Coordination Change on the Strength of Amorphous Silica." Science, vol. 241, pp. 1072-1074, 26 August 1988.
51
Meyer, H.W. "investigation of the H~ersonic Flotield Surrounding aSh~ed Charge Jet."BRL-TR-2883, U.S. Army Ballistic Research Laboratory, Aberdeen Proving Ground, MD,December 1987.
Proctor, B. A., 1.Whitney, and J. W. Johnson. “The Strength of Fused Silica.” Proceedings ofthe Royal Society of London Ser. A, vol. 297, pp. 534-557, 21 March 1967.
Pugh, E. M., R. V. Heine-Geldern, S. Foner, and E. Mutschler. “Kerr Cell Photography ofHigh Speed Phenomena.” Journal of Adied Physics, vol. 22, pp. 487-493, April 1951.
Sugiura, H., K. Kondo, and A. Sawaoka. “Dynamic Response of Fused Quartz in thePermanent Densification Region.” Journal of Applied Physics, vol. 52, pp. 3375-3382,May 1981.
Tate, A. “A Theory for the Deceleration of Long Rods After Impact.” Journal of theMechanics and Physics of Solids, vol. 15, pp. 387-399, 1967.
Tate, A. “Further Results in the Theory of Long Rod Penetration.” Journal of the Mechanicsand Physics of Solids, vol. 17, pp. 141–150, 1969.
Viard, J. “Hugoniot Curve of Vitreous Silica and Crystallization Under Shock.” Com~tesRendus. Academie des Sciences (Paris), vol. 249, pp. 820-822, 1959.
Wackerle, J. “Shock-Wave Compression of Quartz.” Journal of Ar@ied Physics, vol. 33,pp. 922-937, March 1962.
Weyl, W. A. Couloured Glasses. Published by the Society of Glass Technology - England,Distributed by State Mutual Book and Periodical Services, NY, 1951.
Zernow, L., D. Garfinkle, D. Buhman, and J. Burchfield. “Final Report on the Evaluation ofNew Armor Concepts.” Report no. 220, Shock Hydrodynamics Inc., Sherman Oaks, CA,April 1975.
Zernow, L., and G. Hauver. “Study of Jet Penetration Into Glass Targets.” Sh~ed CharcaeJournal, April 1955.
52
Meyer, H. W. "Investigation of the Hypersonic Flowfield Surrounding a Shaped Charge Jet." BRL-TR-2883, U.S. Army Ballistic Research Laboratory, Aberdeen Proving Ground, MD, December 1987.
Proctor, B. A., I. Whitney, and J. W. Johnson. "The Strength of Fused Silica." Proceedings of the Royal Society of London Ser. A, vol. 297, pp. 534-557, 21 March 1967.
Pugh, E. M., R. V. Heine-Geldern, S. Foner, and E. Mutschler. "Kerr Cell Photography of High Speed Phenomena." Journal of Applied Physics, vol. 22, pp. 487-493, April 1951.
Sugiura, H., K. Kondo, and A. Sawaoka. "Dynamic Response of Fused Quartz in the Permanent Densification Region." Journal of Applied Physics, vol. 52, pp. 3375-3382, May 1981.
Tate, A. "A Theory for the Deceleration of Long Rods After Impact." Journal of the Mechanics and Physics of Solids, vol. 15, pp. 387-399, 1967.
Tate, A. "Further Results in the Theory of Long Rod Penetration." Journal of the Mechanics and Physics of Solids, vol. 17, pp. 141-150, 1969.
Viard, J. "Hugoniot Curve of Vitreous Silica and Crystallization Under Shock." Comptes Rendus. Academie des Sciences (Paris), vol. 249, pp. 820-822, 1959.
Wackerle, J. "Shock-Wave Compression of Quartz." Journal of Applied Physics, vol. 33, pp. 922-937, March 1962.
Weyl, W. A. Couloured Glasses. Published by the Society of Glass Technology - England, Distributed by State Mutual Book and Periodical Services, NY, 1951.
Zernow, L., D. Garfinkle, D. Buhman, and J. Burchfield. "Final Report on the Evaluation of New Armor Concepts." Report no. 220, Shock Hydrodynamics Inc., Sherman Oaks, CA, April 1975.
Zernow, L., and G. Hauver. "Study of Jet Penetration Into Glass Targets." Shaped Charge Journal, April 1955.
52
No. of
!Z?@2S
2
1
1
2
2
1
Organization
AdministratorDefenseTechnical Info CenterAlTN: DTIC-DDACameronStationAlexandria,VA 22304-6145
CommanderU.S. Army Materiel CommandAlTN: AMCDRA-ST5001 Eisenhower AvenueAlexandria, VA 22333-0001
CommanderU.S. Army Laboratory CommandAlTN: AMSLC-DL2800 Powder Mill RoadAdelphi, MD 20783-1145
CommanderU.S. Army Armament Research,
EhWdODmt?nt, and Enaineerina Center
No. of
GQll!?S
1
1
1
1
A_tTN: $MCAR-IMI-I - - (class. Only)l
Picatinny Arsenal, NJ 07806-5000
CommanderU.S. Army Armament Research,
Development, and Engineering Center (uncla= WIIY)l
AlTN: SMCAR-TDCPicatinny Arsenal, NJ 07806-5000
DirectorBenet Weapons Laboratory 1U.S. Army Armament Research,
Development, and Engineering CenterAlTN: SMCAR-CCB-TLWatervliet, NY 12189-4050
Unclaaa. only)l Commander 2U.S. Army Armament, Munitions
and Chemical CommandAlTN: AMSMC-IMF-LRock Island, IL 61299-5000 1
1 DirectorU.S. Army Aviation Research 3
and Technology ActivityAlTN: SAVRT-R (Library)MIS 219-3Ames Research CenterMoffett Field, CA 94035-1000 1
10
Organization
CommanderU.S. Army Missile CommandAlTN: AMSMI-RD-CS-R (DOC)Redstone Arsenal, AL 35898-5010
CommanderU.S. Army Tank-Automotive CommandAlTN: ASQNC-TAC-DIT (Technical
lnformatllon Center)Warren, Ml 48397-5000
DirectorU.S. Army TRADOC Analysis CommandAlTN: ATRC-WSRWhite Sands Missile Range, NM 88002-5502
CommandantU.S. Army Field Artillery SchoolAlTN: ATSF-CSIFt. Sill, OK 73503-5000
CommandantU.S. Army Infantry SchoolAlTN: ATSH-CD (Security Mgr.)Fort Benning, GA 31905-5660
CommandantU.S. Army Infantry SchoolAlTN: ATSH-CD-CSO-ORFort Benning, GA 31905-5660
Air Force Armament LaboratoryAlTN: WL/MNOlEglin AFB, FL 32542-5000
Aberdeen Provina Ground
Dir, USAMSAAAlTN: AMXSY-D
AMXSY-MP, H. Cohen
Cdr, USATECOMATTN: AMSTE-TC
Cdr, CRDEC, AMCCOMAlTN: SMCCR-RSP-A
SMCCR-MUSMCCR-MSI
Dir, VLAMOATTN: AMSLC-VL-D
Dir, BRLAlTN: SLCBR-DD-T
53
No. of No. of Copies Organization Copies Organization
2 Administrator 1 Commander Defense Technical Info Center U.S. Army Missile Command ATTN: DTIC-DDA ATTN: AMSMI-RD-CS-R (DOC) Cameron Station Redstone Arsenal, AL 35898-5010 Alexandria, VA 22304-6145
1 Commander Commander U.S. Army Tank-Automotive Command U.S. Army Materiel Command ATTN: ASQNC-TAC-DIT (Technical ATTN: AMCDRA-ST Informatilon Center) 5001 Eisenhower Avenue Warren, M I 48397-5000 Alexandria, VA 22333-0001
1 Director 1 Commander U.S. Army TRADOC Analysis Command
U.S. Army Laboratory Command ATTN: ATRC-WSR ATTN: AMSLC-DL White Sands Missile Range, NM 88002-5502 2800 Powder Mill Road Adelphi, MD 20783-1145 Commandant
U.S. Army Field Artillery School 2 Commander ATTN: ATSF-CSI
U.S. Army Armament Research, Ft. Sill, OK 73503-5000 Development, and Engineering Center
ATTN: SMCAR-IMI-I (Class. on1Y)1 Commandant Picatinny Arsenal, NJ 07806-5000 U.S. Army Infantry School
ATTN: ATSH-CD (Security Mgr.) 2 Commander Fort Benning, GA 31905-5660
U.S. Army Armament Research, Development, and Engineering Center (Unclass. on1Y)1 Commandant
ATTN: SMCAR-TDC U.S. Army Infantry School Picatinny Arsenal, NJ 07806-5000 ATTN: ATSH-CD-CSO-OR
Fort Benning, GA 31905-5660 1 Director
Benet Weapons Laboratory 1 Air Force Armament Laboratory U.S. Army Armament Research, ATTN: WUMNOI
Development, and Engineering Center Eglin AFB, FL 32542-5000 ATTN: SMCAR-CCB-TL Watervliet, NY 12189-4050 Aberdeen Proving Ground
Unclass. onlY)1 Commander 2 Dir, USAMSAA U.S. Army Armament, Munitions ATTN: AMXSY-D
and Chemical Command AMXSY-MP, H. Cohen ATTN: AMSMC-IMF-L Rock Island, IL 61299-5000 1 Cdr, USATECOM
ATTN: AMSTE-TC 1 Director
U.S. Army Aviation Research 3 Cdr, CRDEC, AMCCOM and Technology Activity ATTN: SMCCR-RSP-A
ATTN: SAVRT-R (Library) SMCCR-MU MIS 219-3 SMCCR-MSI Ames Research Center Moffett Field, CA 94035-1000 1 Dir, VLAMO
ATTN: AMSLC-VL-D
10 Dir, BRL ATTN: SLCBR-DD-T
53
No. of
@@ Organization
No. of
GQ12@Organization
1 DirectorCentral Intelligence AgencyAlTN: W. Waltman, OSWR/OSD/GPWBP.O. BOX 1925Main StationWashington, DC 20505
1 CommanderU.S. Army Intelligence AgencyForeign Science and Technology
CenterAll_N: M. Scott Mingledorlf220 Seventh Street, NECharlottesville, VA 22901-5396
1 U.S. Army Research OfficeATTN: Dr. K. IyerP.O. Box 12211Research Triangle Park, NC 27709
5 DirectorU.S. Army Materials Technology
LaboratoryAlTN: SLCMT-MRD,
Dr. G. BishopDr. S-C ChouDr. D. ViechnickiDr. D. DandekarMr. P. Woolsey
Arsenal StreetWatertown, MA 02172-0001
1 DirectorDefense Advanced Research
Projects AgencyATTN: LTC J. H. Beno1400 Wilson Blvd.Arlington, VA 22209-2308
1 Air Force Armament LaboratoryAlTN: AD/CZL (W. Dyess)Eglin Air Force Base, FL 32542-5000
3 Los Alarrms National LaboratoryATTN: Dr. G. E. Cort, MS K574
Dr. R. Karpp, MS P940Dr. L. M. Hull, MS J960
P.O. E!OX 1663
Los Alamos, NM 87545
3
2
1
1
1
1
1
1
1
Lawrence Livermore NationalLaboratory
AlTN: Dr. L. Glenn, MS L-200Mr. J. Reaugh, MS L-290Mr. B. Moran, MS L-200
P.O. Box 808Livermore, CA 94550
Sandia National LaboratoriesAlTN: Dr. M. J. Forrestal
Dr. Dennis GradyP.O. BOX 5800Albuquerque, NM 87185
Southwest Research InstituteAlTN: Dr. C. E. Anderson, Div. 6P.O. Drawer 28510San Antonio, TX 78284
California Research & TechnologyATTN: Dr. D. Orphal5117 Johnson DrivePleasanton, CA 94566
General Research CorporationAlTN: Dr. A. Charters5383 Hollister AvenueSanta Barbara, CA 93160-6770
Battelle, Edgewood OperationsAl’TN: R. Jameson, Suite 2002113 Emmorton Park RoadEdgewood, MD 21040
E. 1.DuPont DeNemours & CompanyAlTN: B. Scott
Chestnut Run - CR 702Wilmington, DE 19898
Univ. of Dayton Research Inst.AITN Dr. S. J. BlessDayton, OH 45469
Zernow Technical Services, inc.ATTN: Dr. Louis Zernow425 W. Bonita Ave., Suite 208San Dimas, CA 92121
54
No. of Copies Organization
1
5
3
Director Central Intelligence Agency AnN: W. Waltman, OSWR/OSD/GPWB P.O. Box 1925 Main Station Washington, DC 20505
Commander U.S. Army Intelligence Agency Foreign Science and Technology
Center AnN: M. Scott Mingledorff 220 Seventh Street, NE Charlottesville, VA 22901-5396
U.S. Army Research Office AnN: Dr. K. Iyer P.O. Box 12211 Research Triangle Park, NC 27709
Director U.S. Army Materials Technology
Laboratory AnN: SLCMT-MRD,
Dr. G. Bishop Dr. S-C Chou Dr. D. Viechnicki Dr. D. Dandekar Mr. P. Woolsey
Arsenal Street Watertown, MA 02172-0001
Director Defense Advanced Research
Projects Agency AnN: LTC J. H. Beno 1400 Wilson Blvd. Arlington, VA 22209-2308
Air Force Armament Laboratory AnN: AD/CZL (W. Dyess) Eglin Air Force Base, FL 32542-5000
Los Alamos National Laboratory AnN: Dr. G. E. Cort, MS K574
Dr. R. Karpp, MS P940 Dr. L. M. Hull, MS J960
P.O. Box 1663 Los Alamos, NM 87545
54
No. of Copies Organization
3
2
1
1
1
1
Lawrence Livermore National Laboratory
AnN: Dr. L. Glenn, MS L-200 Mr. J. Reaugh, MS L-290 Mr. B. Moran, MS L-200
P.O. Box 808 Livermore, CA 94550
Sandia National Laboratories AnN: Dr. M. J. Forrestal
Dr. Dennis Grady P.O. Box 5800 Albuquerque, NM 87185
Southwest Research Institute AnN: Dr. C. E. Anderson, Div. 6 P.O. Drawer 28510 San Antonio, TX 78284
California Research & Technology AnN: Dr. D. Orphal 5117 Johnson Drive Pleasanton, CA 94566
General Research Corporation AnN: Dr. A. Charters 5383 Hollister Avenue Santa Barbara, CA 93160-6770
Battelle, Edgewood Operations AnN: R. Jameson, Suite 200 2113 Emmorton Park Road Edgewood, MD 21040
E. I. DuPont DeNemours & Company AnN: B. Scott Chestnut Run - CR 702 Wilmington, DE 19898
Univ. of Dayton Research Inst. AnN Dr. S. J. Bless Dayton, OH 45469
Zernow Technical Services, Inc. AnN: Dr. Louis Zernow 425 W. Bonita Ave., Suite 208 San Dimas, CA 92121
.—
No. of
- Organization
1 Dr. R. J. Eichelberger409 Catherine StreetBel Air, MD 21014
2 Teledyne Brown EngineeringArmor Technology, Strategic
Systems DivisionATTN: Mr. D. L. Puckett
Dr. D. N. HansenCummings Research Park300 Sparkman Drive, NWHuntsville, AL 35807-7007
55
No. of Copies Organization
Dr. R. J. Eichelberger 409 Catherine Street Bel Air, MD 21014
2 Teledyne Brown Engineering Armor Technology, Strategic
Systems Division AnN: Mr. D. L. Puckett
Dr. D. N. Hansen Cummings Research Park 300 Sparkman Drive, NW Huntsville, AL 35807-7007
55
No. ofCopies Organization
1 Mr. D. E. FinchAA4 DivisionRARDE(FH),SevenoaksKent TN14 76P, UK
1 Mr. Gerard SolveCenter D’Etudesde Gramat46500 Gramat, France
1 Mr. Patrick BarnierEtablissment Technique de BourgesCarrefour de Zero - Nerd - Route
de GuerryBP712 18015 Bourges Cedex France
1 Dr. U. HornemannFraunhofer-lnstitut,EMIInstitutsteilWeil am RheinPostfach 1270D-7858 Weil am Rhein, Germany
1 Dr. Ives RemiliieuxChef du DepartmentCompartment des MateriauxEtabfissementTechnque Central
de L’armement16 bis Avenue Prieurde la Cote
d’Or94114 Arcueil Cedex France
1 Dr. FlorenceTardivelCompadmentdes MateriauxEtablissementTechniqueCentral
de L’arrnement16 bis Avenue Prieurde la Cote
d’Or94114 Arcueil Cedex France
56
No. of Copies Organization
1 Mr. O. E. Finch AA4 Division RAROE(FH}, Sevenoaks Kent TN14 7BP, UK
1 Mr. Gerard Solve Center O'Etudes de Gramat 46500 Grarnat. France
1 Mr. Patrick Barnier Etablissment Technique de Bourges Carrefour de Zero - Nord - Route
de Guerry BP712 18015 Bourges Cede x France
1 Dr. U. Hornemann Fraunhofer-Institut. EMI Institutsteil Weil am Rhein Postfach 1270 0-7858 Weil am Rhein, Germany
1 Dr. Ives Remillieux Chef du Oepartement Compartement des Materiaux Etablissement Technique Central
de L'armement 16 bis Avenue Prieur de la Cote
d'Or 94114 Arcueil Cedex France
1 Dr. Florence Tardivel Compartment des Materiaux Etablissement Technique Central
de L'armement 16 bis Avenue Prieur de la Cote
d'Or 94114 Arcueil Cedex France
56
USER EVALUATION SHEET/CHANGE OF ADDRESS
This laboratory undertakes a continuing effort to improve the quality of the reports itpublishes. Your comments/answers below will aid us in our efforts.
1. Does this report satisfy a need? (Comment on purpose, related project, or other area ofinterest for which the report will be used.)
2. How, specifically, is the report being used? (Information source, design data, procedure,source of ideas, etc.)
3. Has the information in this report led to any quantitative savings as far as man-hours ordollars saved, operating costs avoided, or efficiencies achieved, etc? If so, pIeaseelaborate.
4. General Comments. What do you think should be changed to improve future reports?(Indicate changes to organization, technical content, format, etc.)
BRL Report Number BRL-TR-3273 Division Symbol
Check here if desire to be removed from distribution list. _
Check here for address change. _
Current address: OrganizationAddress
DEPARTMENT OF THE ARMYDirectorU.S. Army Ballistic Research LaboratoryATTN:SLCBR-DD-TAberdeen Proving Ground, MD 21005-5066
OFllCIALBUSINESS I BUSINESSREPLY MAILFIRST CUSS ffRMIT h 0001, M%, MO
Postage will be paid by addressee
DirectorU.S. Army Ballistic Research LaboratoryATTN: SLCBR-DD-T
II NOPOSTAGENECESSAllVIFMAILED
INTl+EUNITEE)STAIES
Aberdeen Proving Ground, MD 21005-5066
USER EVALUATION SHEET/CHANGE OF ADDRESS
This laboratory undertakes a continuing effort to improve the quality of the reports it publishes. Your comments/answers below will aid us in our efforts.
1. Does this report satisfy a need? (Comment on purpose, related project, or other area of interest for which the report will be used.)
2. How, specifically, is the report being used? (Information source, design data, procedure, source of ideas, etc.)
3. Has the information in this report led to any quantitative savings as far as man-hours or dollars saved, operating costs avoided, or efficiencies achieved, etc? If so, please elaborate.
4. General Comments. What do you think should be changed to improve future reports? (Indicate changes to organization, technical content, format. etc.)
BRL Report Number _____ B_RL_-_TR_-_3_2_7_3_ Division Symbol __________ _
Check here if desire to be removed from distribution list.
Check here for address change. __
Current address: Organization Address
DEPARTMENT OF THE ARMY I Director U.S. Army Ballistic Research Laboratory AnN: SLCBR-OO-T Aberdeen Proving Ground, MD 21005-5066
OFRCIAL BUSINESS BUSINESS REPLY MAIL ARST CLASS PERMIT rtJ 000', APG, MO
Postage will be paid by addressee
Director U.S. Army Ballistic Research Laboratory ATTN: SLCBR-DD-T Aberdeen Proving Ground, MD 21005-5066
NO POSTAGE NECESSARY
IF MAILED IN THE
UNITED STATES