Week 10 Bullet penetrating a Bucket Challenge

INTRODUCTION-

The Ansys explicit dynamics analyis system enables us to capture the physics of short duration events for the products that undergo highly nonlinear, transient dynamic forces.

OBJECTIVE-

The objective for this simulation is to use three different non linear materials for the bucket and analyse their behaviour for the same velocity of the bullet.

1. Stainless steel NL
2. Copper alloy NL
3. Aluminium alloy NL

PROCEDURE-

• This simulation is carried out in Explicit Dynamics analysis system.
• Copper alloy NL material is assigned to the bucket and Tantalum material is assigned to the Bullet.Stiffness behaviour for the bullet is set as rigid.

GEOMETRY

Properties of Tantalum material: -

• Body Interaction is set to frictionless between the bucket and the bullet.

MESHING-

Sizing is provided to two edges of the bucket.Element size is kept as 4mm for the bucket.Default mesh is used for the bullet.

BOUNDARY CONDITION-

• Fixed support is provided to the bottom face of the bucket.
• The bullet is provided a velocity of 139,000 mm/s along the negative X-axis.

ANALYSIS SETTINGS-

• The end time for the analysis is 0.01
• Maximum Energy error is set to 5.The initial, Minimum and maximum time step is set to be Program Controlled.

RESULTS-

CASE-I: Stainless steel NL is used as material for the bucket.

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CASE-II: Copper alloy NL is used as material for the bucket.

CASE-III: Aluminium alloy NL is used as material for the bucket.

The results from the above table can be summed up in the following table: -

Cases	Material	Maximum Equivalent Stress(MPa)	Total Deformation (mm)
I	Stainless Steel NL	6791.3	1390
II	Copper Alloy NL	5152.7	1390
III	Aluminium Alloy NL	1203.7	1390

CONCLUSION-

• The higher density and hardness of the material, the more the material will resist the penetration of the bullet.
• Total Deformation is same in all the three cases since there is no change in bullet velocity for all the three cases.