Week - 4 - Crash Box Simulation

AIM:

     To simulate the crash box provided with the mesh.

PROCEDURE:

1.Importing the model given.

     

DEFINING MATERIAL PROPERTIES: 

2.The material used here is Mild steel with 0.3 as poisson's ratio. A non linear material property was given. Tangent modulus and failure criteria were given to ensure that material is going to break after crossing certain strain.

3.Material properties are given by Keyword manager > MAT > 024-piecewise linear plasticity.

DEFINING SECTION PROPERTIES FOR THE CRASH BOX:

4.The value of ELFORM is given as 16 for the shell element with thickness of 1.2mm.

  

ASSIGINING CONTACTS FOR THE GIVEN CRASH BOX:

5.The part deforms so much that it contacts itself. This is a case of self contact where the given crash box is both slave and master and in the case LS-Dyna specifies slave only.

CREATING RIGID WALL:

6.Here the distance in X-direction is kept for 270mm which is more than the default because it need some distance to impact the rigid wall.

     

ASSINGING INTIAL VELOCITY:

7.Intial velocity of 13.88mm/ms is given to crash box along X-direction.

HOURGLASS ENERGY:
     

9.The termination time is given as 10m/s.

RESULT:

Case:1 The shell thickness as 1.2mm

1.Plot of all energies:

2.Acceleration Plot of a Node:

     

3.Von-mises stress : Maximum Stress = 210 MPa.

4.Effective Plastic Strain: Maximum Plastic Strain = 0.0325509

  

5.Maximum Directional Stress along X-axis = 154 MPa.

6.Maximum Directional Stress along Y-axis = 173.4 MPa

   

Case-2: The shell thicness as 1.5mm

1.Plot of all energies:

   

2.Acceleration plot of a node:

     

3.Von-Mises Stress : Maximum Stress = 178 MPa

  

4.Effective Plastic Strain : Maximum Strain = 0.033531

5.Maximum Directional Stress along X-axis = 145 MPa.

6.Maximum directional stress along Y-Axis = 178 MPa

RESULT:

     Thus the simulation of the crash box is performed.