1

Program Objectives

•Determine the viability of using FEA as a tool for predicting small arms ammunition terminal ballistic performance

•Evaluate the effectiveness of various small arms projectiles, after they have penetrated through metal barriers

•Determine the viability of using FEA as developmental tool for small arms ammunition and weapon system development

In support of PM-MAS and JSSAP development programs:

2

“Lethality”

“Lethality”

Probability of Hit

Bullet-Target Interaction•Location of hit•Target Composition•Projectile Ballistics

Target Reaction to Hit

Project Focus

Probabilities

Incapacitation

Warfight Actions

Target Actions

3

Create Model• Diverse projectile configurations and calibers evaluated

• M855, MK262, M995, M855/.265, M855/.308, M855/Pb, M855/Al, M855/ WC

• Targets: 1/8” Mild Steel, 3/8” Mild Steel, ¼” RHA. ¼” RHA 30 ob• Material research

Simulate effectiveness1. Use FEA to Simulate ballistic impact with barrier material2. Use CFD* as well as analytical means to determine post-barrier

projectile drag mechanics3. Use FEA* as well as analytical/empirical models to simulate the

impact of the post-barrier projectile into ballistic gelatin4. Use physical/empirical models quantify the potential

effectiveness against a human target

Evaluate• Briefly compare effectiveness variations against user needs

Approach

* On going efforts

4

Technical Background

V x( ) Vo2 1

a U⋅Vo

⎛⎜⎝

⎞⎟⎠

2+

⎡⎢⎢⎣

⎤⎥⎥⎦

e

ρ CD⋅ A⋅

m− x⋅⎛⎜⎝

⎞⎟⎠⋅

a U⋅Vo

⎛⎜⎝

⎞⎟⎠

2−

⎡⎢⎢⎢⎣

⎤⎥⎥⎥⎦

⋅:=

∑ Δ=x

VPimEKE 2)(2

3) Velocity decay information, as well as retained mass from LS-Dyna used to feed EKE equation, providing the final estimation of effectiveness in the human Thorax.

1) LS-Dyna impact model generates mass, velocity, shape and orientation of projectiles after passing through a barrier.

2) LS-Dyna output put into Sturdivan-Bexan equations to predict subsequent yaw history in 20% gelatin. Simultaneously, LS-Dyna output with Surdivan-Bexan yaw history placed into Peters equation to predict velocity decay in gelatin

5

Damaging Soft Targets

Energy Deposit rate and penetration depth

Post Barrier Damage, as a result of projectile mass

Remember…“Ballistics vs. Logistics”

Slow Rate

Good PD

Fast Rate

Poor PD

Fast Rate

Good PD

Largest EKE

6

Candidates for Study

(.223 cal)

7

Baseline

Residual Velocites for M855 Penetrating 10-gage Mild Steel Plate

0

500

1000

1500

2000

2500

3000

1000 1500 2000 2500 3000 3500

Impact Velocity (fps)

Res

idua

l Vel

ocity

(fps

)

ARL Test Data LS-Dyna Data

M855 vs. 3/8" A36 Steel

0

500

1000

1500

2000

2500

3000

2300 2500 2700 2900 3100 3300

Impact Velocity (ft/sec)

Res

idua

l Vel

ocity

(ft/s

ec)

ARL Test Data LS-Dyna Data

Plug from MK262

M995 tip erosion M855 penetrator

deformation

8

Simulations: 1/8” mild steel, 2500fps

M99

5

MK

262

M85

5-W

C

M85

5-A

L

M85

5-P

B

M85

5-30

8

M85

5-26

5

M85

5

9

Simulations ¼” RHA, 3000fps

M99

5

MK

262

M85

5-W

C

M85

5-30

8

M85

5-26

5

M85

5

10

Retained Mass

Penetrating Mass for Simulated Projectiles Penetrating 10-gage Mild Steel Plate

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

1000 1500 2000 2500 3000 3500 4000

Impact Velocity (fps)

Ret

aine

d M

ass

(gra

ins)

M855 MK262 M995

Mv3/2

Recall…

AVCF D2

21 ρ=

11

Velocity Increase?

Velocity Differnential, front to rear in projectile

20000

22000

24000

26000

28000

30000

32000

34000

36000

38000

0.00E+00 1.00E-05 2.00E-05 3.00E-05 4.00E-05 5.00E-05 6.00E-05 7.00E-05 8.00E-05

Time (sec)

Velo

city

(inc

h/se

c)

M995 Carbide, Front M995 Carbide, Rear MK262 Lead, Front MK262 Lead, Rear

“soft” bullet

“hard” bullet

“fluid

hammer

”

12

Compiling the Simulated Results

Residual Velocities of Simulated Impacts(0.375" A36 steel, BHN 155, 0 Degree Obliquity)

020040060080010001200140016001800200022002400260028003000

150017001900210023002500270029003100

Impact Velocity (fps)

Res

idua

l Vel

ociy

(fps

)

M855, Nominal M855/.265 cal M855/.308 calM855-WC-pen MK262 M995M885/Al M855/Pb

Residual Velocities of Simulated Impacts1/8" Mild Steel "NATO Plate"

0200400600800100012001400160018002000220024002600280030003200

80010001200140016001800200022002400260028003000

Impact Velocity (fps)R

esid

ual V

eloc

iy (f

ps)

M855, Nominal M855, Scaled to 0.265M855, Scaled to 0.308 M855, Aluminum PenetratorM855, Lead Penetrator M855, Tungsten PenetratorMK262 M995

Harder targets to defeat will push user towards AP type ammo

Heavier projectiles have lower V50’s and carry more mass through lighter barriers

14

Evaluating the Results by RANGE

Effectivenss 1/8" mild steel

0

200

400

600

800

1000

1200

1400

1600

1800

2000

M855 M855/265 M855/308 M855/Al M855/Pb M855/WC MK262 M995

EKE

(joul

es)

0m 100m 300m

Effectivenss 3/8" mild steel

0

100

200

300

400

500

600

M855

M855/265

M855/308

M855/Al

M855/Pb

M855/W

C

MK262

M995

EKE

(joul

es)

0m 100m 300m

Effectiveness after 1/8” Mild SteelZero to 300m

Effectiveness after 3/8” Mild SteelZero to 300m

300m M16

0m M16

300m M16

M995 penetrates when others cant……but how effective is it after the barrier?

Effectiveness at a given RANGE is more useful to the user…

M16/M855 EKE, no barrierM855 better thru plate than on bare at close range?

15

Trade Offs

Effectivenss vs. Weight, against 1/8" mild steel

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

20.0

M855 M855/265 M855/308 M855/Al M855/Pb M855/WC MK262 M995

0m 100m 300m

WeightRequirement

What range is most important

to the warfighter?

Effectivenss 1/8" mild steel

0

200

400

600

800

1000

1200

1400

1600

1800

2000

M855 M855/265 M855/308 M855/Al M855/Pb M855/WC MK262 M995

EKE

(joul

es)

0m 100m 300m

Weighing ballistics against logistics

16

Summary

1/8” Mild Steel 3/8” Mild Steel ¼” RHA

M855-.308 caliber M995 M995

M855-.265 caliber M855-WC-pen M855-WC-pen

M855-WC-pen M855-308.cal M855-.265cal

M855 M855-.265 cal M855

Qualitative look at top 4 candidates against each target

Requirements + Performance + Trade-space + logistics = Choice

MK262, M855-AL, M855-PB all significantly lower overall

17

Conclusions

•Simulations correlate well, in most cases, to test data•Limit velocities for M855 against RHA, and Mils Steel matched ARL test data•All lead bullets may require fine-tune•¼” RHA material properties may require fine-tune

•Simulations can be used to improve the projectile development process•Simulations show sensitivity to geometric and material property changes•Simulations enable comparative, scientific analysis•100% predictive capability still difficult without calibrating test data•Simulations reduce product development time•Simulations improve product quality

•Putting a harder penetrator in the M855 is a good overall improvement

•Intermediate caliber can balance range with penetration capability effectively