NEW METHODOLOGY FOR SIMULATING FRAGMENTATION MUNITIONS · NEW METHODOLOGY FOR SIMULATING...

Tank-automotive & Armaments COMmand

U.S. Army, TACOM-ARDEC, Picatinny Arsenal, NJ

NEW METHODOLOGY FOR SIMULATINGFRAGMENTATION MUNITIONS

V. Gold, E. Baker*, K. Ng and J. Hirlinger

*Presented By: Dr. Ernest L. Baker

Report Documentation Page

Report Date 09Apr2001

Report Type N/A

Dates Covered (from... to) -

Title and Subtitle New Methodology for Simulating Fragmentation Munitions

Contract Number

Grant Number

Program Element Number

Author(s) Gold, V; Baker, E; Ng, K.; Hirlinger, J.

Project Number

Task Number

Work Unit Number

Performing Organization Name(s) and Address(es) U.S. Army, TACOM-ARDEC, Picatinny Arsenal, NJ

Performing Organization Report Number

Sponsoring/Monitoring Agency Name(s) and Address(es) NDIA (National Defense Industrial Association) 211Wilson Blvd, STE. 400 Arlington, VA 22201-3061

Sponsor/Monitor’s Acronym(s)

Sponsor/Monitor’s Report Number(s)

Distribution/Availability Statement Approved for public release, distribution unlimited

Supplementary Notes Proceedings from the 36th Annual Gun & Ammunition Symposium & Exhibition 9-12 April 2001Sponsored by NDIA

Abstract

Subject Terms

Report Classification unclassified

Classification of this page unclassified

Classification of Abstract unclassified

Limitation of Abstract UU

Number of Pages 16


Fragmentation ModelingOutline

• Introduction• Background• Modeling Methodology• Natural Fragmentation• Preformed Fragmentation• Conclusions


• TACOM-ARDEC Warheads• Long history of warheads design• Technology development• Application

• Fragmentation Ammunition Requirements– ALACV, OCSW, OICW, M203 upgrade– Lightweight ammunition– Lethal fragmentation, various approaches

Fragmentation ModelingIntroduction


• Natural Fragmentation– Limited lethality due to poor size distribution– Good structural characteristics (G load)

• Preformed and Scored Fragmentation– High lethality potential– Reduced structural integrity, efficiency issues

• Combined Fragmentation– Natural AND preformed/scored fragmentation– Multiple materials (eg: steel and tungsten)– Maintain structural integrity where required, use

preformed/scored fragmentation elsewhere– Require new modeling methodology

Fragmentation ModelingBackground


• Warhead Mechanics (early time)– Arbitrary Lagrangian/Eulerian High Rate Continuum

Modeling: CALE (LLNL) finite difference program– Velocity and Mass Distributions

• Fragmentation Modeling– Hybrid Analytical and Empirical Approach– Natural Fragmentation: Mott based model– Preformed/Scored Fragmentation: Experimentally

based size distribution

Fragmentation ModelingModeling Methodology


Fragmentation ModelingNatural Fragmentation: CALE

t=0 µsec, V/V0=1

t=8 µsec, V/V0=3

t=20 µsec, V/V0=14

ExplosiveHardened steel shell

Copper shaped charge liner

R

z

ΘCopperjet

Steelfragments v

r



0 15 30 45 60 75 90 105 120 135 150 165 180

θ , degrees

0.0

0.1

0.2

0.3

0.4M

ass,

m/m

exp

5µsec, V/V0≈1.810µsec, V/V0≈4.320µsec, V/V0≈14.130 µsec, V/V0≈31.9Experimental Data


0 15 30 45 60 75 90 105 120 135 150 165 180

θ , degrees

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

0.18

0.20

Vel

oci

ty, c

m/µ

s

CALE-MOTT analyses, t=20µsecExperimental DataCALE-MOTT analyses, t=8µsec



Fragmentation ModelingNatural Fragmentation: Mott

∆θ

θj

Ri

rj

(Ri,zi)

R

z

Stress Release WaveFracture

Region UnderPlastic Expansion

Region StressRelieved

A2

B2

B2

A2

B1

A1A1B1

vj


( )2/1

0

−

= jm

jj eNmN µ

32/32

=

j

jFj V

rPγρ

µ

j

jj

mN

µ=0

Fragment Size Distribution:

Total Number of Fragments:

γ is a statiscally based materialdependant constant




0 5 10 15 20 25Normalized fragment mass m/µ

0.0

0.5

1.0

1.5

2.0N

orm

aliz

ed n

umbe

r of

fra

gmen

ts, N

/Ne

xp

Experimental DataCALE-MOTT analyses, t=20µs, γ =30CALE-MOTT analyses, t=8µs, γ=30CALE-MOTT analyses, t=8µs, γ=12CALE-MOTT analyses, t=8µs, γ=5

γ calibration γ=12 final value, V/V0=3 (t=8µs)


0 15 30 45 60 75 90 105 120 135 150 165 180

Θ , degrees

0.00

0.25

0.50

0.75

1.00

1.25N

umbe

r of

fra

gmen

ts, N

/Ne

xp

CALE-MOTT analyses, N0, t=8µsecExperimental Data


γ=12 final value, V/V0=3 (t=8µs)


t=0µsec , V/V0=1

t=20µsec, V/V0=4

t=30µsec, V/V0=6.8

R

z

ΘCopper jet

vrSteel fragments

Explosive Steel shell

Copper shaped charge liner

Fragmentation ModelingPreformed Fragmentation: CALE


0 15 30 45 60 75 90 105 120 135 150 165 180

θ , degrees

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

0.18

0.20V

elo

city

, cm

/µs

t=10µsect=20µsect=30µsec

Fragmentation ModelingPreformed Fragmentation: CALE

Liner/Jet

Case


0 15 30 45 60 75 90 105 120 135 150 165 180

Θ , degrees

0

10

20

30

Num

ber

of fr

agm

ents

Preformed, 2µ0 = 3grains, t=10µsec , V /V0=3.4

Fragmentation ModelingPreformed Fragmentation: Analysis


• New Fragmentation Simulation Capability• Natural Fragmentation• Preformed and Scored Fragmentation• Combined Fragmentation

– Required new modeling methodology– Natural/Scored/Preformed, multiple materials– Currently being applied on the ALACV program

Fragmentation ModelingSummary

Date post:	28-Jun-2020
Category:	Documents
Upload:	others
View:	6 times
Download:	0 times

NEW METHODOLOGY FOR SIMULATING FRAGMENTATION MUNITIONS · NEW METHODOLOGY FOR SIMULATING...

Documents