Week - 4 - Crash Box Simulation

Aim: Create the solver deck and perform the Carsh box simulation.

Procedure:

1)Given, the keyword file extracted from the meshing.( Hypermesh)

2)First add a material to the part. So, using the 001_elastic in the MAT group, Rho=7.83e-3, E=2.07e5, PR=0.3. (Units: g, mm, ms)

3)Initially a Shell section thickness of 1.2mm is created representing the box.

4)Both section ID and the Material ID are assigned to the part.

5)For the crash box simulation a Rigid wall is to be created. So, using the create entity option, a rigid wall is created and is translated to a distance of 30mm. The important note here is, the direction of the rigidwall should be towards the simulation, i.e. tail position of the arrow should be greater than the head part of the arrow.Now th rigid wall is created.

6)Now for the motion of the box, velocity is used from the initial keyword option. First we should create a nodeset ID and a value of -14 mm/ms is given, the direction of velocity should assigned properly.

7)A control termination is assigned with end time of 5 units and the time step of 0.5 units.

8)To calulate the forces at a section, nodeid and shellid has to be created and provide them in the cross_section_set of the database keyword.

9)GLSTAT,SECFORC are specified in the ASCII database and Binary d3plot is also provided to the database.

Conclusion:

1)The kinetic energy of the crash box w.r.t time:

2)Cross section force along the length of the crashbox:

3)Acceleration plot of a node on the crash box:

4)Stress and Strain variation along the length of the crash box:

5)Acceleration plot of crash box with thickness of 1.5mm:

From the acceleration plots it can be seen that with increase in the thickness, the decceleration is huge in case of high thickness part and the range of acceleration and decceleration is changing with change in thickness.

The executed results are proper, because for the collision is taking place after 2ms which as expected.