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Bullet Impact on Steel and Kevlar Bullet Impact on Steel and Kevlar Bullet Impact on Steel and Kevlar Bullet Impact on Steel and Kevlar® ® ®/Steel /Steel /Steel /Steel Armor Armor Armor Armor – – Computer Modeling and Computer Modeling and Computer Modeling and Computer Modeling and Experimental Data* Experimental Data* Experimental Data* Experimental Data* ... 52312317

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Bullet Impact on Steel and KevlarBullet Impact on Steel and KevlarBullet Impact on Steel and KevlarBullet Impact on Steel and Kevlar®®®®/Steel /Steel /Steel /Steel Armor Armor Armor Armor –––– Computer Modeling and Computer Modeling and Computer Modeling and Computer Modeling and

Experimental Data*Experimental Data*Experimental Data*Experimental Data*

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"���#�$��� ���� �� ( ( ( (Body armorBody armorBody armorBody armor))))

"���#�$��� ���� �� ( ( ( (Body armorBody armorBody armorBody armor))))

"������ ��%&'����(��)�� ���� (Steel jacket bullet)(Steel jacket bullet)(Steel jacket bullet)(Steel jacket bullet)

"������ ��%&�� ��� (Armor(Armor(Armor(Armor----piercing bullet)piercing bullet)piercing bullet)piercing bullet)

���*+ ����� ��%&��(����,����%&�������(�-%�%.�����

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"��� ��%& ....338 Winchester magnum338 Winchester magnum338 Winchester magnum338 Winchester magnum

Scientific name : 8.5 × 63.5 B

Ignition : center fire

Caliber type : Civilian and military caliberPrimer diameter : 5.33 mm

Data from Cartwin pro.

Velocity 2780 feet/sec. (842.16 m/s)Bullet 225 grains SP(Soft pointed)

Data from Catridges of the world.

"����*+ ����� ��%&'�� AAAA----frameframeframeframe

/0 ....338 Winchester magnum338 Winchester magnum338 Winchester magnum338 Winchester magnum

1. �"#��+)�,������ �" �4�����%���!5���%6�"�������% ����&��.�� ��������"�������*7������ (Computer Hydrocode

analyses) ������� AUTODYN � � �������%!��%6���� �%�8�� �����

2. �"#����������������!5���%6�"�������% ����&��.�� ��������%!��%�� �%�8�� �����

3. �"#����������������9���������������%������"�������*7������ (Computer Hydrocode analyses)

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1. AUTODYN computer code (Computer Hydrocode

analyses).

2. Ruger M70 bolt action Rifle.

3. .338 Winchester magnum (A-frame bullet).

4. Mild Steel plate.

5. Kevlar® panel.

6. Digital Vernier.

AUTODYN computer code (Computer Hydrocode analyses)

� Computer Hydrocode

�#� ����8�� ��������"��������' ������� �%���!5���%��%/0��������'�% 2 �� 3 ���� � ����"������������!5���%�1��������� �������%� ��&����5�������� ���� �%���!5���%":��������%���%���%; ���!"�!��<�����%� -%��%6���������%6����������5�� �� �9&��������� ()�%!���������'��%����� -�; ()�%��%������-������%������' ���� %��������� �������%��#-�������91��� ����� ��%������-!91��5���<����������������������

�10��/�� $���1�/$� AUTODYN computer

code (Computer Hydrocode analyses)

Define the problem:Equation of stateConstitutive modelBoundary conditionsMesh geometryEulerian or Lagrangian?Choose material properties

Calculate the forces due to:External forcesPressure forcesConstitutive modelBoundary ConditionsArtificial stability forces

Update the mesh by moving vertices of fluxing material between cells

Advance time

Is solution reached?Yes

No

Stop

Ruger M70 Ruger M70 Ruger M70 Ruger M70

bolt action bolt action bolt action bolt action

RifleRifleRifleRifle

.338 Winchester magnum (A-frame bullet)

Mild Steel plate thickness 14.275 mm

Kevlar® panel thickness 20 mm

Digital Vernier

LeadLeadLeadLead

� Equation of State : Shock

� Reference Density (g/cm3) 11.35

� Gruneisen Coefficient : 2.77

� Parameter C1 (m/s) 2.051E03

� Parameter S1 : 1.46

� Strength Model : Von Mises

� Shear Modulus (KPa) 5.6E6

� Yield Strength (KPa) 5.0E3

CopperCopperCopperCopper

� Equation of State : Shock

� Reference Density (g/cm3) 8.93

� Gruneisen Coefficient : 1.99

� Parameter C1 (m/s) 3.94E03

� Parameter S1 : 1.489

� Strength Model : Von Mises

� Shear Modulus (KPa) 4.5E7

� Yield Strength (KPa) 7.0E4

KevlarKevlarKevlarKevlar� Equation of State : Puff

� Reference Density (g/cm3) 1.29

� Parameter A1(kPa) 8.21E06

� Parameter A2(kPa) 7.036E07

� Parameter A3(kPa) 0.0

� Gruneisen Coefficient : 0.35

� Expansion Coefficient : 0.25

� Sublimation Energy (J/Kg) : 8.23E06

� Parameter T1(kPa) 0.0

� Parameter T2(kPa) 0.0

� Reference Temp (K) 0.0

� Specific Heat (C.V.) (J/kgK) 0.0

� Strength Model Von Mises

� Shear Modulus 3.0E7

� Yield Strength 3.0E5

� Tensile Strength -2.6E5

SteelSteelSteelSteel� Equation of State : Shock

� Strength Model Johnson-Cook

� Reference Density (g/cm3) 7.896

� Gruneisen Coefficient 2.17

� Parameter C1 (m/s) 4.569E03

� Parameter S1 : 1.49

� Reference Temperature (K) : 300

� Shear Modulus (kPa) : 8.18E07

� Yield Stress (kPa) : 5.17106E05

� Hardeni ng Constant (kPa) : 2.75E05

� Hardeni ng Exponent : 0.36

� Strain Rate Constant : 0.022

� Thermal Softening Exponent : 1.0

� Melting Temperature (K) 1.811E03

� � -������� 1 ��3�����' ��� Computer hygrocode ����������������*� ������+)�,��� 2 ��<�- ��<���� 1 �����������#�� ����&��� �����������2������%- ��<���� 2 �����������#�� ����&��� ������ ������������������ �

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� � -������� 2 ��3�����%�#��8�� ��!��%�� �%�8�� �����������4���� Sandia

National Laboratories. ����5��������%!��%� -% 2 ��<����*� �������� -������� 1

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Computer Hydrocode Computer Hydrocode Computer Hydrocode Computer Hydrocode AnalysesAnalysesAnalysesAnalyses

Ballistic testing Ballistic testing Ballistic testing Ballistic testing in Laboratoryin Laboratoryin Laboratoryin Laboratory

Bare mild steel plate Bare mild steel plate Bare mild steel plate Bare mild steel plate thickness 14.275 mmthickness 14.275 mmthickness 14.275 mmthickness 14.275 mm

Kevlar panel Kevlar panel Kevlar panel Kevlar panel thickness 20 mm thickness 20 mm thickness 20 mm thickness 20 mm

and then steel and then steel and then steel and then steel plate 14.275 mmplate 14.275 mmplate 14.275 mmplate 14.275 mm

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�%���������/0����(�� ���/��� ����������� ������ 2 /�� $ ����� ����

���0����� �� 338 338 338 338

winchester bulletwinchester bulletwinchester bulletwinchester bullet

�1���0�$�'���0��������/�� $��( 1

AUTODYN model of a .338 Winchester magnum

A-Frame hunting bullet impacting the steel.

14.275 mm (0.562 in)

8.585 mm (0.338 in)

AUTODYN AUTODYN AUTODYN AUTODYN simulation of simulation of simulation of simulation of the bullet the bullet the bullet the bullet impacting the impacting the impacting the impacting the steel platesteel platesteel platesteel plate.

Impact crater dimensions ,Impact crater dimensions ,Impact crater dimensions ,Impact crater dimensions ,

Measurements are made to steel surface.Measurements are made to steel surface.Measurements are made to steel surface.Measurements are made to steel surface.

AUTODYN model of a .338 Winchester magnum

A-Frame hunting bullet

impacting the Kevlar® Armor and then steel plate.

14.275 mm (0.562 in)

20 mm (0.787 in)

AUTODYN simulation AUTODYN simulation AUTODYN simulation AUTODYN simulation of the bullet impacting of the bullet impacting of the bullet impacting of the bullet impacting

the Kevlarthe Kevlarthe Kevlarthe Kevlar®®®® Armor and Armor and Armor and Armor and steel plate behind steel plate behind steel plate behind steel plate behind

KevlarKevlarKevlarKevlar®®®® Armor .Armor .Armor .Armor .

Impact crater dimensions,Impact crater dimensions,Impact crater dimensions,Impact crater dimensions,

Measurements made toMeasurements made toMeasurements made toMeasurements made to

steel surfaces.steel surfaces.steel surfaces.steel surfaces.

.338 Winchester Magnum Ruger M70 hunting rifle..338 Winchester Magnum Ruger M70 hunting rifle..338 Winchester Magnum Ruger M70 hunting rifle..338 Winchester Magnum Ruger M70 hunting rifle.

Bullet impact crater on steel plate along

with a cross-section cut.

BulletBulletBulletBullet----induced bulge on back side of steel.induced bulge on back side of steel.induced bulge on back side of steel.induced bulge on back side of steel.

Comparison of AUTODYN predicted crater Comparison of AUTODYN predicted crater Comparison of AUTODYN predicted crater Comparison of AUTODYN predicted crater with experimental crater.with experimental crater.with experimental crater.with experimental crater.

Bullet impact on steel plate when protect by one Bullet impact on steel plate when protect by one Bullet impact on steel plate when protect by one Bullet impact on steel plate when protect by one sheet of 20 mm Kevlarsheet of 20 mm Kevlarsheet of 20 mm Kevlarsheet of 20 mm Kevlar®®®®....

Back view of bullet impact on steel plate when Back view of bullet impact on steel plate when Back view of bullet impact on steel plate when Back view of bullet impact on steel plate when protect by one sheet of 20 mm Kevlarprotect by one sheet of 20 mm Kevlarprotect by one sheet of 20 mm Kevlarprotect by one sheet of 20 mm Kevlar®®®®....

Comparison of predicted and measured bullet induced craters in steel following penetration of one 20 mm Kevlar® panel.

Front side of Kevlar® panel showing bullet entry hole.

Back side of KevlarBack side of KevlarBack side of KevlarBack side of Kevlar®®®® panel where bullet exited.panel where bullet exited.panel where bullet exited.panel where bullet exited.

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���+)�,����� -%��-���%� �2�� ���������9��������������������%���&��.������%��%& ��� ��� ����� AUTODYN (Computer hydrocode) *� ������� �%��

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� Century Dynamics, AUTODYN User and Theory Manual, 2001.

� Nosler, Inc, Nosler Reloading Guide, 2002.

� Gareth S. Collins, An Introduction to Hydrocode Modeling, 2002.

� Frank C. Barnes, Cartridges of the world, 2006.

� Cartwin Pro, 2008.

� www. Google.com

� www.sciencedirect.com

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