Buckling of Composite Cylindrical Shell-PPT

7/23/2019 Buckling of Composite Cylindrical Shell-PPT

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R.V. COLLEGE OF ENGINEERING, BANGALORE

Thesis TitleDESIGN OF POLYMER COMPOSITE SHELL STRUCTURES FOR UNMANNED

UNDERWATER VEHICLE APPLICATIONS

Carried out at

RESEARCH AND DEVELOPMENT, R.V. COLLEGE OF ENGINEERING

Bangalore

Under The Guidance Of

Dr. H. N. NARASIMHA MURTHY

Prof. and Dean PG Studies (Mechanical)

by

MOORTHY G RV!"PMM!


2/60

Unmanned Underater !ehicles

"ecently# UU! ha$e emer%ed as a $ital tool offshore and underater

a&&lications due to ad$ancements in material technolo%y# artificial

intelli%ence# sensor technolo%y# communication technolo%y# ima%e

&rocessin% besides many others.

The &rimary a&&lications include offshore drillin%# oceano%ra&hic studies#underater ins&ection and maintenance# sur$eillance and security and many

others.

The %lobal "O! mar'et is estimated to be .* billion in *+, and is

e-&ected to re%ister a CG" of *+./ in *+0. The %lobal U! mar'et is

estimated to be ,12 million in *+, and is e-&ected to re%ister a CG" of

3.01/ in *+0.


3/60

Many 4a$al forces of the orld ha$e been addin% UU!5s to their fleet for boostin%

their unmanned arfare ca&abilities.

The US 4a$y had released a UU! master &lan in *+++ to establish a roadma& for

de$elo&in% the UU! ca&abilities# and hence effecti$ely introduce UU!5s into the6leet hich ill si%nificantly contribute to the 4a$y5s control of the maritime battle

s&ace.

The roadma& as re$ised and u&dated in *++, and *+# considerin% the

de$elo&ments. The Penta%on5s bud%et re7uest for unmanned maritime systems

(includin% unmanned surface) research# de$elo&ment# testin%# &rocurement#

o&erations and maintenance is a&&ro-imately 8, million for the *+ to *+1

&eriod.

The "oyal 4a$y is already usin% UU!5s to hel& sto& 9ran layin% mines in shi&&in%

lanes and also are bein% considered for de&loyment for the &irate:infested aters off

Somalia. They are further e-&lorin% ho to use unmanned systems to su&&ort the $ast

ran%e of future na$al ca&abilities that ill &ro$ide orld:leadin% carrier stri'e from

*+*+.


4/60

9n the sia:Pacific re%ion s&ecifically# the ;"9C countries ill &ro$e to be the

emer%in% mar'ets for the UU! ith their acti$ities in the scientific research# oil

and %as sectors and military a&&lications.

China5s


5/60

s far as 9ndia is concerned# our country has a coastline of 218.8 'm# the area and

a$era%e de&th of 9ndian ocean is 23#118#+++ 'm@ and 3A0+ m res&ecti$ely. Due to

this $ast interaction ith sea# 9ndia has been one of the leadin% %lobal contender of

UU! technolo%y and a&&lications.

Some of the &otential a&&lications of these unmanned underater $ehicles in

94D9 are data %atherin%# military artificial intelli%ence %atherin%# mine detection

and elimination# oil and %as e-&loration and marine ener%y besides many others.

The UU!s are bein% de$elo&ed and used by defense or%ani?ations and research

institutes# hich some of them ha$e de$elo&ed their on.

The !isa'ha&atnam:based 4a$al Science and Technolo%y Baboratory (4STB)# a

D"DO firm# has been de$elo&in% and testin% a series of UU!5s for maritime

security# straddlin% coastal and &ort defense to dee&:sea o&erations.


6/60

The Central Mechanical n%ineerin% "esearch 9nstitute (CM"9)# Dur%a&ur a

constituent establishment of the Council of Scientific and 9ndustrial "esearch

(CS9") built a UU! named EU! 1+F in technical collaboration ith the 9ndian

9nstitute of Technolo%y (99T)# hara%&ur on Han# *+. The U! as ca&able of

carryin% out many underater ater o&erations includin% ocean floor:ma&&in%#

sur$eillance acti$ities and oceano%ra&hic studies

4ational 9nstitute of Oceano%ra&hy# Goa ha$e successfully de$elo&ed a small

U!# Maya and are loo'in% forard to commerciali?e the U! technolo%y.

cademic research &ro=ects Matsya from 99T:;ombay# mo%h from 99T:Madras

ha$e been successfully de$elo&ed and are &artici&atin% in national and

international com&etitions.


7/60

Materials considered for UU! structures

The ma=or re7uirements for a material to be used in an UU! are hi%h buoyancy for

better maneu$erability# or' at ocean floors for better $isibility and hence should

ha$e hi%h stability limit# should be immersed underater for lon% &eriods ithout

corrosion related &roblem# should ha$e %ood sound absor&tion ability for &erformin%

military o&erations in stealth mode# etc.

>ence# steel# aluminium and titanium are some of the traditional choices used for

UU! structures# hich usually re7uires one or more tradeoffs beteen abo$e

mentioned re7uirements.

6or e-am&le# in case of Trieste ;athysca&he# the hea$y ei%ht of the thic' hull had to

be com&ensated by usin% hu%e %asoline container to increase buoyancy. To account

for corrosion related &roblems so&histicated coatin%s or e-&ensi$e titanium had to be

used in many.


8/60

>oe$er# com&osite materials manufactured usin% to or more

com&limentary materials can be used to o$ercome these discre&ancies oftheir metallic counter&arts.

Com&osites materials ha$e %ood buoyancy hich increases

maneu$erability of UU!5s# ha$e loer ei%ht to stren%th ratios hich

hel&s to achie$e lon% endurance a %reater de&th# the most im&ortant of all

is their resistance to corrosion# ha$e %ood acoustic trans&arency# besides

many others.

Com&osites may also reduce cost and su&&ly &roblems that are associated

ith com&le- hi%h:density nic'el aluminium bron?e castin%s and titanium

castin%s.


9/60

Many UU! manufacturin% com&anies and %o$ernment ha$e been fundin%research on use of com&osite materials for UU! structures.

Ocean Gate 9nc. (Seattle# Iash.# US) announced on u%. * *+3 the

com&letion of the initial carbon fiber hull desi%n and feasibility study for

its ne-t:%eneration manned submersible Cyclops.

The dee& %lider de$elo&ed by Uni$ersity of Iashin%ton School ofOceano%ra&hy for oceano%ra&hic studies# initially had de&th of o&eration

of +++m hich is no bein% increased to 8+++m by usin% carbon fiber

reinforced com&osite &ressure hull.

96"M" ;"ST# a 6rench research institute for the e-&loitation of the

sea has been fundin% many research for desi%n of com&osite &ressure hulls. On March *8# *+*# Canadian film director Hames Cameron &iloted the

Deepsea challenger to reach record brea'in% de&th +#0+A m. The &ilot

s&here as made of carbon reinforce com&osite.

Use of com&osite materials for

UU! structures


10/60

Pol#$er Ma%r&' Co$(o)&%e) *PMC+ a) UUV)%r-%ral $a%er&al)

PMCs have several advantages over metallic materials for UUV structural applications. Hence, globally research is focused on

studying the behaviour of UUVs using PMCs.

Major advantages of PMCs include high specific stiffness, eight saving up to !" # hen compared ith $l and up to %"#

hen compared ith steel, e&cellent corrosion and chemical resistance, better design fle&ibility, cost effective production of

comple& '( structure, improved acoustic performance and lo maintenance.

Potential polymeric resins for these applications include polyester, isopolyester, epo&y, vinylester, phenolics and the fibre

reinforcements include glass, carbon and )evlar. *able +. presents relative merits and demerits of these materials.

-ibre materials used for marine applicationsare glass, aramid )evlar/, and carbon. Chopped strand mats, oven fabrics andunidirectional fibres are used as reinforcements. 01glass being cost effective is idely used in naval structures. $ramid fibres

possess greater strength and toughness, high static, fatigue and impact strength. 2ut, they are difficult to cut and machine.

Carbon fibres possess greater elastic modulus, fatigue strength and service life than those of glass fibres. Hence, carbon

fibres outperform aramid and glass fibres.

C.3.3mith 4%5 e&amined UUVs using 6-7P and C-7P ith epo&y as resin for buc8ling, creep, compressive fatigue, impact

strength and effect of prolonged immersion combined ith pressure.

*anguy et. al. 49, +"5 analy:ed thin alled composite vessels made of 6-7P and C-7P ith epo&y as resin using numerical

tool and correlated the results ith e&perimental and analytical methods.

(ere8 6raham 4++, +5 developed a large scale model of deep diving pressure hull using C-7P and tested the model for a

depth of over ; 8m.

V. Carvelli et. al. 4+'5 tested glass5 performed numerical and e&perimental buc8ling for filament ound C-7P cylinders subjected to hydrostatic

pressure for UUV applications.

L&%era%re Re&e/0


11/60

De)&gn -on)&1era%&on) o2 UUV S%r-%re)

UU! structures ha$e to ithstand hi%h e-ternal &ressure. They are %enerally com&osed of conical# s&herical#

cylindrical and elli&tical &rofiles and fail mainly due to buc'lin%.

Cylindrical and elli&tical &rofiles are more &rone to buc'lin% than s&herical and conical &rofiles because of

%reater slenderness J3K. uthors J0# +# 3 : *,K re&orted desi%n of UU! considerin% thic' J,# **K and thin J0#

3# 2# and 0K shells.

6ilament indin% is idely ado&ted for fabricatin% UU! structures alon% ith o&timi?ation of indin% an%le for

buc'lin% resistance.

Chul:Hin Moon et.al. J,K studied combination of helical and hoo& indin% and bondin% of metal flan%es forassembly.

C.T.6. "oss et.al. J1K re&orted that the com&osite structures e-&erienced to forms of buc'lin%# namely# shell

instability (or non:symmetric bifurcation buc'lin%) and %eneral instability.

Tan%uy Messa%er et.al. J0K re&orted J0+*L8+L3+1L8+L0+K as o&timi?ed stac'in% se7uence.

Seon%:>a >ur et.al. J8K re&orted fastenin% of the com&onents by bolted =oints alon% ith adhesi$e for lea'

&roof =oints.

S. Srini$asanet.al. J0K re&orted the effect of uncertainties in %eometric and material &arameters in the

manufacture of filament ound com&osite laminate tubes on matri-:dominated first &ly failure.

>. >ernande?:Moreno et. al. J*3K re&orted that N 11o is the o&timal indin% an%le for buc'lin% resistance.


12/60

De)&gn A((roa-3e) o2 UUV )%r-%re)

N$er&-al a((roa-3

Se$eral authors re&orted &rediction of buc'lin% &ressure of underater $ehicles by 6a&&roach. ;oth commercial and in:house codes are ado&ted for the in$esti%ation. Ihile

authors J+# 3# 1 :2# 0# *# **# *,K used 4SS# others such as J*1# 3AK em&loyed

;


13/60

Re2eren-e) Mo1el Con)&1era%&on) Loa1 Con)&1era%&on) Na%re o2 anal#)&)Ma%er&al

Con)&1era%&on)

Ele$en%

Con)&1era%&on)

Chul:HinMoon et. al.

JK

Thic' alled cylinderse-ternal hydrostatic

&ressure

Binear and non:

linear 6 analysisC6"P 6our node elements

Tan%uy

Messa%er et.

al. J*K

Thin com&osite

6ilament ound cylinder>ydrostatic &ressure

4on:linear 6M

stability analysis

CarbonL e&o-y and

%lassL e&o-y

Mindlin com&osite

laminated shell

elements

!. Car$elli et.

al. J3K

Underater $ehicle:

assembly

-ial stresses

considered in

hydrostatic &ressure

4umerical non:

linear buc'lin%

analysis

:%lass o$en

ro$in% ith

&olyester resin

8A++ shell elements

Seon%:>a

>ur et. al. J,KCom&osite cylinders

-ternal hydrostatic

&ressure

Binear and non:

linear 6 analysis

Carbon:e&o-y

&re&re% ta&e

A:node laminated

shell# lement 30

Myun%:>un

im et. al J1K

6ilament:ound

com&osite cylinder

-ternal hydrostatic

&ressure

4onlinear buc'lin%

analysis

com&osite carbon

fiber T2++

Shell A and the

solid Solsh0+

>ae:oun%

Hun% et. al. J8K

Cylindrical com&osite

$essel hulls installed ith

steel flan%e

;uc'lin% &ressure and

e-ternal hydrostatic

&ressure

Binear and

nonlinear buc'lin%

analysis

Carbon fiber T2++ ShellA

;ao&in% Cai

et. al. J2K

Com&osite lon% cylinders

and steel flan%es

-ternal hydrostatic

&ressure

Static analysis and

buc'lin% analysis

Carbon:e&o-y

com&osite

Shell element

S>BB00

hairul 9?man

bdul "ahim

et. al. JAK

Circular cylindrical sha&e

ith end ca&s closure

-ternal

hydrodynamic

&ressure

;uc'lin% analysisluminium alloy

8+8:T8

9so: &arametric solid

element

Tan%uy

Messan%er J0K

Thin: alled laminated

cross:&ly cylinders

-ternal &ressureBinear buc'lin%

analysis

Carbon:e&o-y

com&osite

>ybrid# com&osite

laminated# shell

element

Re&e/ o2 B-4l&ng S%1&e) o2 Un1er/a%er Ve))el)


14/60

,

Pro5le$ De2&n&%&on


15/60

"esearch Ob=ecti$e Study of com&arati$e buc'lin% &erformance of metallic i.e. >i%h stren%th steel (> A+)#

titanium alloy (Ti1)# aluminum alloy (l 2+21) hich are currently em&loyed for underater $essels

and &olymer com&osite such as carbon L $inylester and %lass L $inylester as alternate materials for

cylindrical $essels of len%th 81+ mm and 31+ mm inner diameter by numerical a&&roach.

Predictin% Critical ;uc'lin% Pressure# stresses and strains of &olymer com&osite cylindrical $essels oflen%th A*1 mm and inner diameter 21 mm (carbon L $inylester and %lass L $inylester for + mm and 1

mm thic' $essels ith N 11+fibre orientation) in static condition by usin% 6

6abricatin% cylindrical shells (%lass L $inylester) of dimensions A*1 mm len%th# 21 mm 9D and 1 mm

and + mm thic'ness and N 11+fibre orientations by 6ilament Iindin% method.

Performin% buc'lin% test usin% the ;uc'lin% tester for the 6ilament Iound tubes made of %lass L$inylester ith fibre orientation N 11+and determinin% corres&ondin% strains.

Com&utin% stresses analytically based on the e-&erimental strain data for the cylinders by usin%"educed Stiffness Matri-

Predictin% the buc'lin% &erformance of underater $essels under combined e-ternal &ressure and a-ialloads.

Predictin% the ;uc'lin% beha$iour of underater cylindrical $essels in mo$in% condition by 6 usin%4SS.* 6BOT"4 C6D

!alidation of -&erimental# nalytical# and 6 results.


16/60

Pro(o)e1 a((roa-3e) 2or 5-4l&ng 5e3a&or o2 -#l&n1r&-al )3ell)

2or UUV a((l&-a%&onCo$(ara%&e 5-4l&ng (er2or$an-e o2 $e%all&- an1 (ol#$er -o$(o)&%e n1er/a%er e))el) 5# FEA

B-4l&ng Re)(on)e o2 Pol#$er Co$(o)&%e S3ell) 5# FEA


17/60

Pro(o)e1 a((roa-3e)..

E'(er&$en%al B-4l&ng Re)(on)e o2 -o$(o)&%e )3ell)

Von6M&)e) )%re))e) o2 -#l&n1r&-al )3ell) 5# RSM


18/60

Pro(o)e1 a((roa-3e)..

B-4l&ng Re)(on)e o2 C#l&n1r&-al S3ell) n1er -o$5&ne1 3#1ro)%a%&- an1 a'&alloa1&ng 5# FEA

B-4l&ng 5e3a&or o2 n1er/a%er e))el &n $o&ng -on1&%&on 5# FEA


19/60

0

Co$(ara%&e S%1# o2 Me%all&- an1 Pol#$er Co$(o)&%e)

2or Un1er/a%er S%r-%re)

Materials considered for com&arati$e study are hi%h stren%th steel (> A+)# titanium

alloy (Ti1)# aluminum alloy (l 2+21)# %lassLe&o-y and carbonLe&o-y com&osites.The critical buc'lin% &ressure ere calculated by &erformin% ei%en:bu'lin% analysis

in 6 softare 4SS.

The shells of metallic $essels ere discreti?ed usin% S>BB83 4SS element in

hich isotro&ic material &ro&erties of elastic modulus and Poisson5s ratio ere

considered. Ihereas# &olymer matri- com&osites ere modeled usin% S>BB 00#

hich is a linear Bayered Structural Shell lement ith A:node# 3:D shell elementith si- de%rees of freedom at each node.


20/60

The folloin% dimensions ere considered for the study D Q 31+ mm# B

Q 81+ mm. The thic'ness for each material as selected for a critical

buc'lin% &ressure of + MPa.Thic'ness of the structures for each material is &resented in table alon%

ith the res&ecti$e ei%ht sa$in%s.

The results indicated ei%ht sa$in%s of ,8 / for carbonLe&o-y and 3 /

in %lass L e&o-y hen com&ared ith >A+

*+

Ma%er&al HY 7! T& 8 Al "!"8 Car5on9e(o'#

Gla))9e(o'#

Thic'ness(mm)

8.21 A.*1 * 1 A

Iei%ht(%)

0 3.1 3.3 + 3.*


21/60

*

Thic'ness of shells corres&ondin% to Critical ;uc'lin% Pressure of + MPa

Iei%ht of shell structures for Critical ;uc'lin% Pressure of + MPa


22/60

B-4l&ng Te)%er Se%(

E'(er&$en%al B-4l&ng Re)(on)e o2

-o$(o)&%e )3ell)0.


23/60

*3

F&la$en% /on1 )3ell /&%3 2lange)

an1 PU r55er PU r55er) )e1 a) o&l )eal

a) 6ilament ound shells# b) Strain %au%e &ositions# c) Strain %au%e ith cables

Strain indicator used for

measurin% strains


24/60

Re)l%) o2 B-4l&ng Te)% 6

M&-ro)%ra&n) 2or 8$$ %3&-4 e))el *For/ar1+

Position of the strain gauges (deg)

Pe!("Pa)

Cir#u$ferentia% Longitudina%

Position & '& & *+& * *

"i#rostrain

;>? ;'' ;!" ;?; '%" >!" *.-

+"9+ +"?; ++" +++% ;;" ??" -.&

+!'" +>!" +!>" +!> 9>" +"9" +.-

+9?" +9" +9%" +9+> ++" +>+" &.&

>+ '? >' '! +>9> +?'" *.-

%>? %'" %;' ?>? +??" ""> -.&

'"> '"+> '"'9 9"! +%% "+> .&


25/60

M&-ro)%ra&n) 2or 8 $$ %3&-4 e))el

*Reer)e+

Po)&%&on o2 %3e )%ra&n gage) *1eg+

Pe'(,*MPa+

Circumferential Bon%itudinal

Position + 0+ A+ *2+ *8 8*

Microstrain

8+1 ,2 1+8 8,+ 388 ,31 *.1

+1+ 003 +8, +88 8,A 2,* 1.+

,A ,, 30 ,,, 0*0 001 2.1

AA A18 201 A1 0 380 +.+**+A **A1 **A8 **81 30A 800 *.1

*8A *2* *823 *83* 81A 0A, 1.+

*A1 *0,1 *0A8 *A12 2A0 *++1 8.+


26/60

C&r-$2eren%&al )%ra&n) a% ar&o) a((l&e1 3#1ro)%a%&-

(re))re) 2or 8 $$ %3&-4 e))el *Loa1&ng++

C&r-$2eren%&al )%ra&n) a% ar&o) a((l&e1 3#1ro)%a%&-

(re))re) 2or 8 $$ %3&-4 e))el *nloa1&ng++

0 90 180 270 3600

500

1000

1500

2000

2500

3000

3500

*.1 MPa

1 MPa2.1 MPa

+ MPa

*.1 MPa

1 MPa

8 MPa

Po)&%&on o2 )%ra&n gage *Degree+

$&-ro)%ra&n

0 90 180 270 3600

500

1000

1500

2000

2500

3000

3500

*.1 MPa

1 MPa2.1 MPa

+ MPa

*.1 MPa

1 MPa

8 MPa

Po)&%&on o2 )%ra&n gage *Degree+

$&-ro)%ra&n


27/60

Aerage -&r-$2eren%&al )%ra&n) 2or 8 $$ %3&-4 e))el a%

ar&o) a((l&e1 3#1ro)%a%&- (re))re)

*For/ar1 an1 Reer)e+

2.5 5 7.5 10 12.5 15 160

500

1000

1500

2000

2500

3000

3500

6orard

"e$erse

H#1ro)%a%&- Pre))re &n MPa

$&-ro)%ra&n

C&r-$2eren%&al )%ra&n) a) a 2n-%&on o2 a((l&e1 (re))re a%

1&22eren% lo-a%&on) 2or 8 $$ %3&-4 e))el


28/60

M&-ro)%ra&n) 2or ! $$ %3&-4 e))el

Position of the strain gauges (deg)

Pe!,("Pa)

Circumferential @ongitudinal

Position & '& & *+& * *

"i#rostrain

%;> 9"; 9+" 9"+ 9" '!? *.-

+'9 +>?! +>;" +>;" %"" %!" -.&

+%9" "9" +9?! "!" +'! +'!! +.-

";" ''" +>' 9" +!'" +!!" .-

+! !%" '+" !>" +?!" +?!"'.-

''" 9>" '9! %%! "+" +9%" &.-

9> '"" ;" '?>" +>" +%! .&

+!'; >9"" 9'?1+'""

>?!" '%" !" .-

collapse collapse collapse collapse collapse collapse *.&


29/60

C&r-$2eren%&al )%ra&n) 2or ! $$ %3&-4 e))el a% ar&o)

lo-a%&on) a% leng%3/&)e $&1(o&n%

2.5 5 7.5 8.5 9.5 10.5 11 11.50

1000

2000

3000

4000

5000

6000

0

90

180

270

H#1ro)%a%&- Pre))re *MPa+

$&-ro)%ra&n

C&r-$2eren%&al )%ra&n) 2or ! $$ %3&-4 e))el a%

ar&o) a((l&e1 3#1ro)%a%&- (re))re)


30/60

Aerage -&r-$2eren%&al )%ra&n) 2or ! $$ %3&-4

e))el a% ar&o) a((l&e1 3#1ro)%a%&- (re))re)

0

500

1000

1500

2000

2500

3000

3500

2.5 5 7.5 8 .5 9.5 10.5 11 11.5

H#1ro)%a%&- Pre)),re &n MPa

$&-ro)%ra&n


31/60

Colla()e1 Co$(o)&%e C#l&n1era+ Te)%e1 2or 5-4l&ng, 5+ B-4le1 -#l&n1er an1 -+ E'(lo1e1

&e/ o2 %3e 5-4le1 (or%&on

B-4le1 -#l&n1er

E'(lo1e1 &e/


32/60

Buckling Response of PolymerComposite Shells by FEA.

;ased on numerical studies of C.T.6. "oss et.al.J*5 S. Srini$asan et.al.JK ho ha$e

used 4SS 6 Pro%ram ith S>BB B94" B" 00 element to conduct the

buc'lin% analysis element used to conduct the buc'lin% test is : S>BB BM4T :

B94" B" 00 ith 69;" O"94TT9O4 11+# :11+

Elastic Constant GlassEpo!y

E" 45.6 GPa

E# 16.2 GPa

E$ 16.2 GPa

G"# 5.83 GPa

G"$ 5.83 GPa

G#$ 5.78 GPa

%"# 0.27

%#$ 0.49

%"$ 0.278

Speci&c 'ensity 1.7

O"T>OT"OP9C MT"9B P"OP"T9S


33/60

S3ell )%r-%re o2 UUV

Me)3e1 $o1el /&%3 5on1ar# -on1&%&on)

Me)3e1 $o1el o2 -#l&n1r&-al )%r-%re

Me)3e1 $o1el /&%3 n&2or$ e'%ernal (re))re


34/60

BLOC: LANCO; BUC:LING ANALYSIS

;uc'lin% analysis in 4SS as carried out usin% ;BOC B4COR method to

e-tract the i%en $alues to &redict the critical buc'lin% &ressure. The ;loc' Banc?os

method is the best of all the methods and it is recommended for most a&&lications

because of the folloin% reasons

fficient e-traction of lar%e number of modes (,+) in most models

Ty&ically used in com&le- models ith mi-ture of solidsLshellsLbeams etc.

fficient e-traction of modes in a fre7uency ran%e

>andles ri%id:body modes ell


35/60

CBP 2or 8 $$ %3&-4 e))el

C;P Q 6re7uency &&lied Pressure

Q 3.830 *.1

Q 3,.+0 MPa

C;P Q 6re7uency &&lied Pressure

Q 1.80 *.1

Q *.0* MPa

CBP 2or ! $$ %3&-4 e))el


36/60

STATIC ANALYSIS < STRESSES AND STRAINS

Static analysis as &erformed in 4SS to determine thestresses and strains for the cylindrical structures.

FEA )%ra&n) 2or ! $$ an1 8 $$ %3&-4 e))el)

Pressure (bar) FEA *icro+strain , "-

mm thick essel

=8 21

8! ,*0

"8 *,,

78 *,3+

>8 *28

!8 3++*

! 3,1

8 3*A2

Pressure (bar) FEA *icro+strain , "/

mm thick essel

=8 1A1

8! 033

"8 300

!! A88

=8 *33*

8! *200

?! *0A1

)%ra&n) 2or ! $$ %3&-4 e))el )%ra&n) 2or 8 $$ %3&-4 e))el


37/60

FEA )%re))e) 2or ! $$ an1 8 $$ %3&-4 e))el)

Pressure (bar) FEA stresses , "- mm

thick essel (*Pa)

=8 32.+

8! 2,.+*3

"8 .+3,

78 *1.A3A

>8 ,+.8,3

!8 11.,,2

Pressure (bar) FEA stresses , "/ mm thick

essel (*Pa)

#/ 23.679

/- 47.358

0/ 71.037

"-- 94.716

"#/ 118.395

"/- 142.074

"1- 151.546

S%re))e) 2or ! $$ %3&-4 e))el S%re))e) 2or 8 $$ %3&-4 e))el


38/60

Von-Mises stresses of cylindrical shells y !"M#..

;ased on the studies of H. M. Bifshit? et.al.J1K Stresses for the cylinders ere calculated analytically by

usin% e-&erimental strain data by "DUCD ST9664SS MT"9 method. The cylinder falls under

the orthotro&ic material cate%ory. Since the cylinder does not contain any out:of:&lane loads# one can

assume &lane stress condition for the cylinder.

A

Ihere


39/60

S%re)) a% =8 5ar 2or ! $$ %3&-4 e))el

A

Q ,8.80 MPa

* Q +.2 MPa

3 Q +

V* Q +

Substitutin% the $alues of and*in !on:Mises e7uation*ys

*Q ( *)* (* 3)

* (3 )*

Q (,8.80 : +.2)* +.2* ,8.80*

Q 31A0.2*

ys* Q 20,.A

ysQ ,*.38 MPa

3 3

3 3

3

,0., )+ ,.AA )+ +

,.AA )+ )2.11 )+ +

+ + 1.A3 )+

8

8

0+ +

312 +

+

( ) ( )3 8 3 8) ,0., )+ 0)+ )+ ,.AA )+ 312 )+ = +

( ) ( )3 8 3 8* ,.AA )+ 0)+ )+ )2.11 )+ 312 )+ = +


40/60

S%re))e) 2or ! $$ an1 8 $$ %3&-4 e))el)

Pressure (bar) Analytical stresses (*Pa)

=8 ,*.38

8! 8A.8A

"8 02.,

78 +A.81

>8 *+.3

!8 32.3

S%re))e) 2or ! $$ %3&-4 e))el

Pressure

(bar)

Analytical stresses (*Pa)

=8 3.1

8! 1*.1

"8 2.A2

!! 0*.,*

=8 3.+

8! *A.*A

?! ,.80

S%re))e) 2or 8 $$ %3&-4 e))el


41/60

Val&1a%&on o2 E'(er&$en%al -r&%&-al 5-4l&ng (re))re /&%3

%3a% o2 FEA 2or ! $$ %3&-4 e))el

E'(er&$en%al re)l% FEA re)l% De&a%&on

CBP *.+ MPa *.0* MPa 2.*/

Com&arison of -&erimental C;P ith 6 C;P for + mm thic' $essel


42/60

Val&1a%&on o2 E'(er&$en%al )%ra&n) /&%3 %3a% o2

FEA )%ra&n)Pre))re

*5ar+

E'(er&$en%al

M&-ro6)%ra&n

FEA M&-ro6

)%ra&n

De&a%&on

=8 0+8 21 *.+A/

8! ,21 ,*0 3.**/

"8 *+0+ *,, *.,*/

78 *33+ *,3+ ,./

>8 *1A+ *28 1.++/

!8 *0,+ 3++* *.+8/

! 3*++ 3,1 .2/

8 ,0++ 3*A2 3*.0/

Pre))re

*5ar+

E'(er&$en%al

M&-ro6)%ra&n

FEA M&-ro6

)%ra&n

De&a%&on

=8 833 1A1 2.1A

8! +28 033 3.*A

"8 ,1+ 300 3.1

!! 0*+ A88 *.A

=8 *32* *33* .8A

8! *A3+ *200 .+0

?! 3+, *0A1 +.08

Co$(ar&)on o2 E'(er&$en%al )%ra&n)

/&%3 FEA )%ra&n) 2or ! $$ %3&-4 e))el

Co$(ar&)on o2 E'(er&$en%al )%ra&n)

/&%3 FEA )%ra&n) 2or 8 $$ %3&-4 e))el


43/60

E'(er&$en%al an1 FEA S%ra&n) a% ar&o)

a((l&e1 (re))re) 2or ! $$ %3&-4 e))el

*.1 1 2.1 A.1 0.1 +.1 .1+

+++

*+++

3+++

,+++

1+++

8+++ -&erimental microstrain

6 microstrain

A((l&e1 H#1ro)%a%&- Pre) )re *M Pa+

$&-ro)%ra&n

E'(er&$en%al an1 FEA S%ra&n) a% ar&o)

a((l&e1 (re))re) 2or 8 $$ %3&-4 e))el


44/60

Val&1a%&on o2 Anal#%&-al )%re))e) /&%3 %3a% o2

FEA )%re))e)

Co$(ar&)on o2 E'(er&$en%al )%re))e)

/&%3 FEA )%ra&n) 2or ! $$ %3&-4 e))el

Co$(ar&)on o2 E'(er&$en%al )%re))e)

/&%3 FEA )%ra&n) 2or 8 $$ %3&-4 e))el

Pre))re

*5ar+

Anal#%&-al

)%re))e) *MPa+

FEA )%re))e)

*MPa+

De&a%&on

=8 ,*.38 32.+ *.8*/

8! 8A.8A 2,.+*3 2.*/

"8 02., .+3, *.*/

78 +A.81 *1.A3A 3.8/

>8 *+.3 ,+.8,3 ,.,/

!8 32.3 11.,,2 .2A/

Pre))re

*5ar+

Anal#%&-al

)%re))e) *MPa+

FEA )%re))e)

*MPa+

De&a%&on

=8 3.1 *3.820 *,.A1/

8! 1*.1 ,2.31A 0.A/

"8 2.A2 2.+32 .1/

!! 0*.,* 0,.28 *.,*/

=8 3.+ A.301 ,.,2/

8! *A.*A ,*.+2, 0.2/

?! ,.80 1.1,8 8.1/


45/60

Anal#%&-al an1 FEA )%re))e) a% ar&o) a((l&e1 (re))re)

2or ! $$ %3&-4 e))el

*.1 1 2.1 A.1 0.1 +.1+

*+

,+

8+

A+

++

*+

,+

8+

A+

Anal#%&-al )%re))e) *MPa+

FEA )%re))e) *MPa+

A((l&e1 H#1ro)%a%&- Pre)) ,re *MPa+

$&-ro)%ra&n

Anal#%&-al an1 FEA )%re))e) a% ar&o) a((l&e1 (re))re)

2or 8 $$ %3&-4 e))el


46/60

*aterial Properties

Properties %alues

Mod$l$s of %lasticity 71.7GPa

Poisson&s ratio 0.33

'ensity 2.81()cc

Elastic

Constant

Carbon %inyl

ester

Glass %inyl

ester

%1 A3.0* GPa 3*. GPa

%2 A3.0* GPa 3*. GPa

%3 *.+,AA GPa 2.02* GPa

G12 1.,2 GPa 1.A3 GPa

G13 ,.+, GPa 1.8*8 GPa

G23 ,.+, GPa 1.8*8 GPa

V12 +.+3* +.,12

V23 +.,3A* +.,**1

V13 +.,3A* +.,**1

*ale 3 +rtho(onal ,aterial roerties ofcaron) Vinyl ester and (lass) Vinyl ester

i($re 1 a "tac/in( se$ence and,aterial orientation an(le of co,osite

cylinder

i($re 1 "tac/in( of layers

*ale 2 Material roerties of l7075


47/60

FEA Stu2ies of Buckling

i($re 3 Meshed ,odel of

cylindricalessel

i($re 6 Meshed ,odel itho$ndary conditions- o,ined

load

i($re 7 ial co,ressionalied onthe ,odel

i($re 2 Meshed ,odel itho$ndary conditions- %ternal

ress$re

i($re 4 ylinder $nder eternal

ress$re- so,etric ie

i($re 5 ylinder $ndereternal ress$re- "ide ie

Eigen buckling of un2er3ater essels


48/60

Eigen buckling of un2er3ater essels

i($re 8 $c/lin( ,ode shaes for caron) eoyessel s$ected to eternal ress$re

i($re 9 $c/lin( ,ode shaes for caron) eoyessel s$ected to eternal ress$re and aial load

A8,*+A8,*+

,+++

3+++

*+++

+++

+

Pressure (MPa)

6.mic

ro:strain

1l7075

4aron) e-oy

Glass) e-oy

ar a e

A8,*+A8,*+

*1+

*++

1+

++

1+

+

Pressure (MPa)

6.stre

ss(MPa)

1l7075

4aron) e-oy

Glass) e-oy

ar a e

Static buckling of un2er3ater essels

i($re 10 Press$re Vs. % ,icro- strain 15,, thic/ l7075 caron) eoy and (lass)

eoy essels $nder eternal ress$re

i($re 11 Press$re Vs. % stress :15,, thic/ l7075 caron) eoy and

(lass) eoy essels $nder eternal ress$re

'ynamic analysis


49/60

'ynamic analysis

i($re 15 Press$re lot

i($re 16 Meshed re(ion ith o$ndary andloadin( conditions

!es$lts

*aterial

4ateral pressure

% (ms)

4ateral an2 a!ial loa2

% (ms)

t ; 15,, t ; 10,, t ; 15,, t ; 10,,

l 7075 140- 150 90- 100 120- 130 80- 90

aron)eo

y110- 120 70- 80 100- 110 60- 70

Glass)

eoy80- 90 50- 60 70- 80 40- 50

*ale 6 Velocity ran(es for cylinders

' i l i


50/60

'ynamic analysis

a< 15,, thic/ essel < 10,, thic/ esseli($re 18 o,arison of P res$lts of essels $nder eternal hydrostatic ress$re and aial

load

a< 15,, thic/ essel < 10,, thic/ esseli($re 17 o,arison of P res$lts of essels $nder eternal hydrostatic ress$re

A

8

,

*

+

A

8

,

*

+

Criticalbuc'lin%&

ressure(MPa)

l2+21

CarbonL e

GlassL e

!ariable

A+2+8+1+,+3+*+++

2

8

1

,

3

*

+

Criticalbuc'lin%&ressure(MPa)

l2+21

CarbonL e

GlassL e

!ariable

++A+8+,+*++

8

,

*

+

A

8

,

*

+

Criticalbuc'lin%&ressure(MPa)

l2+21

CarbonL e

GlassL e

!ariable

2+8+1+,+3+*+++

8

1

,

3

*

+

Criticalbuc'

lin%&ressure(MPa)

l2+21

CarbonL e

GlassL e

!ariable

%ali2ation


51/60

5able 6 Calculate2 an2 FEA CBP alues for cylin2er un2er hy2rostatic pressure

*aterial

FEA

CBP (*Pa)

Analytical

CBP (*Pa)7 2eiation

FEA

CBP (*Pa)

Analytical

CBP (*Pa)7 2eiation

t 8 "/mm t 8 "-mml7075 17.062 18.34 6.96 7.103 8.58 17.21

aron)

eoy10.318 9.837 4.89 4.141 3.297 25.59

Glass) eoy 5.453 4.8022 13.55 2.256 1.6 29

%ali2ation

*aterial

FEA

CBP (*Pa)

Analytical

CBP (*Pa)

7

2eiation

FEA

CBP (*Pa)

Analytical

CBP (*Pa)

7

2eiation

t 8 "/mm t 8 "-mm

l7075 14.602 12.478 17.02 5.538 4.506 22.9

aron) eoy 9.086 9.834 7.60 3.331 3.295 1.09

Glass) eoy 4.664 4.8 2.83 1.75 1.59 10.06

5able / Calculate2 an2 FEA CBP alues for cylin2er un2er hy2rostaticpressure an2 a!ial loa2

E!perimental result FEA result 'eiation

P 12 MPa 10.987 MPa 9.2 =

*ale 6 o,arison of eeri,ental P that of % for 10 ,, thic/ (lass) eoy essel-';175,, >en(th;825,,

Con-l)&on)


52/60

Con-l)&on)

;ased on the numerical analysis for buc'lin% of underater $essels for an o&eratin% de&th of +++ m the folloin% conclusions ere

arri$ed at

Carbon L $inylester em&loyed for underater shells ( scale) model shoed ei%ht sa$in%s of ,8 / com&ared to hi%h stren%th steel

based on the thic'ness of the shell for sustainin% + MPa buc'lin% &ressure.

Similar sa$in%s of 3 / as obtained for %lass L $inylester hen com&ared ith that of >i%h stren%th steel.

;uc'lin% beha$iour of (* scale) of + mm and 1 mm filament ound cylindrical shells as in$esti%ated by e-&erimental#

numerical and analytical a&&roaches. ;ased on the results folloin% conclusions ere arri$ed at

-&erimental C;P of + mm thic' shell of A*1 mm len%th# 21 mm internal diameter usin% %lassL$inylester as * MPa hereas theC;P of the shell &redicted by 6 as *.0* MPa# shoin% %ood a%reement beteen the e-&erimental and 6 results.

Strain as a function of hydrostatic &ressure from *.1 MPa to +.1 MPa for + mm thic' shell as &redicted by static buc'lin% analysis

of 4SS ith de$iations of .2 / to 3*.0 / from the e-&erimental strains. >i%hest de$iation of 3*.0 / occurred at .1 MPa

because at the onset of buc'lin% the strains increase si%nificantly# hich is not &redicted by the linear static analysis of 4SS.

!on:Mises stresses at different hydrostatic &ressures ere &redicted usin% "SM based on e-&erimental circumferential and

lon%itudinal strains. The !on:Mises stresses &redicted by 6 and "SM closely a%reed ith a ma-imum de$iation of ,., / for +

mm thic' shell.

Strain as a function of hydrostatic &ressure from *.1 MPa to 8 MPa for 1 mm thic' ( * scale) shells as &redicted by linear static

analysis of 4SS ith a ma-imum de$iation of 3.*A / from the e-&erimental strains. These shells ere not loaded to colla&se

&ressure due to the limitations in the tester.

!on:Mises stresses as a function of a&&lied &ressure as obtained analytically and by 6 for 1 mm thic' shells ith ma-imum

de$iations of .1/ to *,.A1 /. These stresses ere deri$ed from the e-&erimental strain data.

Con-l)&on)


53/60

Con-l)&on)

;uc'lin% beha$iour of ( scale) filament ound cylindrical shells under &ure hydrostatic and combined hydrostatic and a-ial loadin% as

in$esti%ated by numerical a&&roach. ;ased on the results# the folloin% conclusions ere arri$ed at

"eduction in C;P for + mm and 1 mm thic' l 2+21 $essel hen the loadin% as chan%ed from &ure hydrostatic &ressure to combined

hydrostatic &ressure and a-ial load ere **.*A / and ,.1A / res&ecti$ely.

Similarly# for carbonL $inylester the reductions in C;P ere *2.,0 / and A.0* /. 6or %lassL $inylester the corres&ondin% $alues ere *8.3, / and

A.*/. This shoed that the &ercenta%e reductions in C;P for + mm thic' $essels ere much %reater than that for 1 mm thic' $essels.

The !on:Mises stresses and strains increased ith increase in hydrostatic &ressure. The microstrains &redicted by 6 for carbon L $inylester and

%lass L $inylester shells ere considerably %reater than those of l 2+21 shell. .

The !on:Mises stresses &redicted by 6 for carbon L $inylester ere %reater hereas for %lassL $inylester they ere close to those of l 2+21.

;uc'lin% &erformance of underater $essels under combined hydrostatic and a-ial loadin% in mo$in% conditions as in$esti%ated by C6D a&&roach.

;ased on the results the folloin% conclusions ere arri$ed at

Carbon L $inylester shells of 1 mm and + mm thic'ness can be safely toed at $elocity of around + mLs and 2+ mLs res&ecti$ely. 6or %lassL$inylester the $elocities ere A+ mLs and 1+ mLs and for l2+21 ,+ mLs and 0+ mLs res&ecti$ely hen only lateral &ressure as considered.

The $elocities reduced by + mLs a&&ro-imately in all the cases hen the combined lateral and a-ial &ressures ere considered.


54/60

S-o(e 2or 2%re )%1&e) The research in$ol$ed e-&erimental# numerical and analytical methods of &redictin% buc'lin% beha$iour of underater shell structures of

metallic and &olymer com&osite structures based on the %eometrical features of e-istin% metallic shells. The methodolo%y ado&ted in the

research can be effecti$ely em&loyed for the desi%n of underater $essels. >oe$er# the research may be e-tended in the folloin% areas

to achie$e underater $essels of &olymer matri- com&osites.

Thou%h the front conical and rear hemis&herical com&onents are not of si%nificance hile establishin% the safe o&eratin% de&ths of

underater $essels# the analysis may be e-tended to full: fled%ed model considerin% flan%es and the =oints.

do&tion of %rid stiffeners may be e-&lored to further stren%then the shells.

Underater $essels are o&erated under ater for s&ecific duration of time althou%h intermittently. Thus# dell time analysis may be

&erformed to establish their durability.

Re2eren-e)


55/60

Re2eren-e). Carl T.6. "oss# conce&tual desi%n of an underater $ehicle# Ocean n%ineerin%# !ol. 33# *++8# &&. *+A2*+,

*. T. >ya'udome.# S. 9shibashi.# . Iatanabe.# >. oshida.# S. Tsu'io'a.# T.o'i.# &&lication to Pressure !essels for Underater !ehicle

of Ma%nesium lloys # 9# *++A# &&. **8:**0.

3. ;lachut.# P. Smith.# ;uc'lin% of multi:se%ment underater &ressure hull# Hournal of Ocean n%ineerin% # !ol. 31# *++A# &&. *,2*8+

,. ;usby.6.".# Undersea !ehicles. Office of the oceano%ra&her of the 4a$y# Iashin%ton.D.C# 0A1.

1. Cho:Chun% Bian%.# Sheau:Ien Shiah.# Chan:un% Hen.# >un%:Ien Chen.# O&timum desi%n of multi&le intersectin% s&heres dee&:

submer%ed &ressure hull# Ocean n%ineerin%# !ol. 3# *++,# &&. 22:00

8. ubbin im.# Ulnyeon im.# Hinsoo Par'.# study on effects of initial deflection on ultimate stren%th of rin%stiffened cylindrical

structure under e-ternal hydrostatic &ressure# Proceedin%s of thirteenth international off:shore and &olar en%ineerin% Conference#

>aaii# US# May *1:3+# *++3

2. hairul 9?man bdul "ahim# bdul "ahim Othman# Mohd "i?al rshad# Conce&tual desi%n of a &ressure hull for an underater &ole

ins&ection robot# 9ndian Hournal of Marine Science# !ol. 3A (3)# *++0# &&. 31*:31A

A. C.S.Smith.# Desi%n of Submersible Pressure >ulls in Com&osite Materials# Marine Structures# !ol. ,# 00# &&. ,:A*

0. Tan%uy Messa%er.# Marius? Pyr?.# ;ernard Gineste.# Pierre Chauchot.# O&timal laminations of thin underater com&osite cylindrical

$essels# Hournal of Com&osite Structures# !ol. 1A# *++*# &&. 1*0:132

+. Tan%uy Messa%er# ;uc'lin% of im&erfect laminated cylinder under hydrostatic &ressure# Hournal of Com&osite Structure# !ol. 13# *++#

&&. 3+:3+2


56/60

. Dere' Graham.# Com&osite Pressure >ulls for dee& ocean submersibles# Com&osite Structure# !ol. 3*# 001# &&. 33:3,3

*. Dere' Graham.# ;uc'lin% of thic' section Com&osite &ressure >ulls# Com&osite Structure# !ol. 31# 008# &&. 1:*+

3. !. Car$elli.# 4.Pan?eri.# C.Po%%i.# ;uc'lin% stren%th of G6"P under ater $ehicle# Hournal of Com&osite Part ; n%ineerin%# !ol.

3*# *++# &&. A0:+

,. Chul:Hin Moon.# 9n:>oon im.# ;ae:>yeon Choi.# Hin:>e eon.# Hin:>o Choi.# ;uc'lin% of filament:ound com&osite cylinders

sub=ected to hydrostatic &ressure for underater $ehicle a&&lications# Com&osite Structures# !ol. 0*# *++# &&. **,**1

1. C.T.6. "oss# . O. O'oto and .P.6. Bittle# ;uc'lin% by General 9nstability of Cylindrical Com&onents of Dee& Sea Submersibles#

&&lied Mechanics and Materials# !ol. 3# *++A# &&.*A0:*08

8. Seon%:>a >ur.# >ee:Hin Son.# Hin:>eeon.# Hin:>o Choi.# Post buc'lin% of com&osite cylinders under e-ternal hydrostatic

&ressure# Hournal of Com&osite Structures# !ol. A8# *++A# &&. ,:*,

2. Myun%:>un im.# Hon%:"ae Cho.# Ion:;yon% ;ae.# Hin:>e eon.# Hin:>o Choi.# San%:"ae Cho and un:Si' Cho.# ;uc'lin%

nalysis of 6ilament:Iound Thic' Com&osite Cylinder under >ydrostatic Pressure# 9nternational Hournal of Precision n%ineerin%

and Manufacturin%# !ol. # *++# &&. 0+0:03

A. H. ;lachut.# P. Smith.# ;uc'lin% of multi:se%ment underater &ressure hull# Ocean n%ineerin%# !ol. 31# *++A# &&. *,2:*8+

0. S. Srini$asan.# ;. ;hattacharya.# Probabilistic failure of filament ound %lass fiber reinforced com&osite tube under bia-ial

loadin%# Proceedin%s of 0thSC Hoint S&ecialty Conference on Probabilistic Mechanics and Structural "eliability# # lbu7uer7ue#

4e Me-ico# Huly *8:*A#*++,


57/60

*+. >ae:oun% Hun%.# Hon%:"ae Cho.# Heon%:oun% >an.# Ioo:>yun% Bee.# Ion:;yon% ;ae.# un:Si' Cho.# Study on ;uc'lin% of

6ilament:Iound Cylindrical Shells under >ydrostatic -ternal Pressure usin% 6inite lement nalysis and ;uc'lin% 6ormula#9nternational Hournal of Precision n%ineerin% and Manufacturin%# !ol. 3# *+*# &&. 23: 232

*. ;ao&in% Cai.# on%hon% Biu.# >ua?hou Bi.# Ren%'ai Biu.# ;uc'lin% analysis of com&osite lon% cylinders usin% &robabilistic finite

element method# MC>49# !ol. 2(1)# *+# &&. ,82:,23

**. hairul 9?man bdul "ahim# bdul "ahim Othman# Mohd "i?al rshad# Conce&tual desi%n of a &ressure hull for an underater &ole

ins&ection robot# 9ndian Hournal of Marine Sciences# !ol. 3A (3)# *++0# &&. 31*:31A

*3. >.>ernande?:Moreno. ;.Douchin.# 6.Collobet# D.cho7ueuse.# P.Da$ies.# 9nfluence of indin% &attern on the mechanical beha$iour of

filament ound com&osite cylinders under e-ternal &ressure#Com&osites Science and Technolo%y# !ol. 8A# *++A# &&. +1+*,

*,. . Ian%# Hun iao.# .C. Rhan%.# method for sol$in% the buc'lin% &roblem of a thin: alled shell# 9nternational Hournal of Pressure

!essels and Pi&in%# !ol. A# *++,# &&. 0+20*

*1. u'bin im.# Ulnyeon im.# Hinsoo Par'.# Study on ffects of 9nitial Deflection on Ultimate Stren%th of "in%:stiffened Cylindrical

Structure under -ternal >ydrostatic Pressure# Proceedin%s of the Thirteenth (*++3) 9nternational Offshore and Polar n%ineerin%

Conference# >onolulu# >aaii# US# *++3# &&. *13+

*8. nde P.6 Bittle.# Carl T.6. "ss.# Daniel short.# Graham .# 9nelastic ;uc'lin% of Geometrically 9m&erfect tubes under e-ternal

>ydrostatic Pressure#Ocean So$erei%nty# !ol. 3 ()# *++A# &&.21:A

*2. G. 6orasassi.# ". Bo 6rano.# ;uc'lin% of 9m&erfect Thin Cylindrical Shell Under Bateral Pressure# Hournal of chie$ements in

Materials and Manufacturin% n%ineerin%# !ol. A# *++8# &&. *A2:*03


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*A. nton >u bner.# Matthias lbie?.# Dietmar ohler## and >elmut Saal## ;uc'lin% of lon% steel cylindrical shells sub=ected to e-ternal

&ressure# Thin Ialled Structures# !ol. ,1# *++2# &&.:2

*0. S. %ha=ari.# . bedia.# >. Sho'atib.# ;uc'lin% and &ost:buc'lin% beha$iour of thin:alled cylindrical steel shells ith $aryin%

thic'ness sub=ected to uniform e-ternal &ressure#Thin:Ialled Structures# !ol. ,,# *++8# &&. 0+,0+0

3+. ". Bo 6rano.# G. 6orasassi.# -&erimental e$idence of im&erfection influence on the buc'lin% of thin cylindrical shell under e-ternal

&ressure#4uclear n%ineerin% and Desi%n# !ol. *30# *++0# &&. 03*++

3. H.". Macay.# 6. !an eulen.# "e$ie of -ternal Pressure Testin% Techni7ues for Shells includin% a 4o$el !olume:Control

Method# -&erimental Mechanics# !ol. 1+# *++# &&.21322*

3*. 4.G.Pe%%.# -&erimental determination of interframe buc'lin% of a rin% stiffened Cylinder# 4ational Defence "esearch and

De$elo&ment ;ranch# Technical Memorandum A0L*+0# 0A0

33. amamoto# "esearch and de$elo&ment of &ast# &resent and future autonomous underater $ehicle technolo%ies# Proceedin% of

9nternational Mater class U! Technolo%y Polar Science:Society Underater Technolo%y,!ol. *A# *++2# &&. 2*8

3,. >on%ei Rhan%# Shu-in Ian%# Modellin% and nalysis of an utonomous Underater !ehicle $ia Multibody System Dynamics#

Proceedin%s of *th 96TOMM Iorld Con%ress# ;esanWon (6rance)# !ol. A:*# *++2

35. ttore# .de ;arros, Hoao# B. D. Dantas# ntonio# M. Pascoal# l%ar de Sa# 9n$esti%ation of 4ormal 6orce and Moment CoefXcients

for an U! at 4onlinear n%le of ttac' and Sidesli& "an%e# 9 Hournal of Oceanic n%ineerin%# !ol. 33(,)# *++A

38. Hian%uo Iu# Chaoyin% Chen# Shun-in Ian%# >ydrodynamic ffects of a shroud Desi%n 6or a >ybrid:Dri$en Underater Glider# Sea

Technolo%y# !ol. 1(8)# *++# &&. ,1:,2


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32. . D. im# ;uc'lin% beha$iour of com&osite &anels usin% the 6inite lement Method# Com&osite Structures# !ol. 38# 008# &&. 33 :

,3.

3A. Barbi Siad# ;uc'lin% of thin:alled orthotro&ic cylindrical shells under uniform e-ternal &ressure.&&lication to corru%ated tin cans#Thin:Ialled Structures# !ol.31# 000#&&. +1.

30. Sathi$el. ".# !en%adesan. S.# and ;hattacharyya. S..# &&lication of non:linear k: turbulence model in flo simulation o$erunderater a-isymmetric hull at hi%her an%le of attac'# Hournal of 4a$al rchitecture and Marine n%ineerin%# !ol. *# *+# &&. ,0:

83.

,+. Sree'ar Gomatam.# !en%adesan. S.# and ;hattacharyya. S..# 4umerical simulations of flo &ast an autonomous underater $ehicle

at $arious drift an%les# Hournal of 4a$al rchitecture and Marine n%ineerin%# !ol. *# *+*# &&. 31:1*.

,. Md. Mashud arim# Md. Mahbubar "ahman# and Md. bdul lim.# 4umerical com&utation of $iscous dra% for a-isymmetric

underater $ehicles# Hournal Me'anical# !ol. (*8)# *++A# &&. 0:*.

Publications


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9nternational :ournal Publications

Moorthy G @arasi,ha M$rthy A.@ Brishna M !a(haendra @ o,aratie "t$dy of Metallic and Poly,er o,osite

"hells for Cnderater Vessels $sin( % International Journal of Ocean System Engineering ol. 3D3

Documents

Buckling of Composite Cylindrical Shell-PPT