Week - 4 - Crash Box Simulation
AIM:
To simulate a crash box test for the given FE model using LS DYNA and to compare the results between two simulations of thickness 1.2mm and 1.5mm of the same given model.
PROCEDURE:
1.First import the given FE model to LS DYNA.The unit system we follow for this process will be gm-mm-ms.
2.Now we have to create two models seperately for 1.2mm and 1.5mm respectively . The section cards will be defined first with ELFORM 2.
3.Then the material is assigned to the crashbox which is linear plasticity (MAT 024) and the values are given assuming it to be steel.
4.Now the created section and material cards are assigned to the Part keyword.
5.Now the rigid wall has to be created for performing the crash.So we can use the RIGIDWALL PLANAR keyword and create it by assuming a distance of 15mm from the crash box.
6.Now the initial velocity has to be provided which is 13.88mm/ms.
7.Now to define contact we are using CONTACT AUTOAMTIC SINGLE SURFACE keyword to establish the contact within the crashbox itself if any contact occurs.
8.Now to record the houglass and sliding energy we activte the CONTROL ENERGY card.
9.Now setup the control termination card to set the end time of the simulation.
10.Now for database files under ASCII activate glstat,matsum,rcforc,rwforc,secforc,sleout and give the time interval as 0.1.In binary d3plot give 0.1 as dt and create a new database card for cross section to record the data at that particular section as it is required.
11.After running the simulation in LS-RUN open the d3plot file and analyse the results.
Von Mises Stress 1.2mm
Von Mises Stress 1.5mm
Strain 1.2 mm
Strain 1.5mm
Here in both the boxes permanent deformation occurs due to the impact and the strain values are almost same.
Nodal acceleration 1.2mm
Nodal acceleration 1.5mm
Energies 1.2mm
Energies 1.5mm
We can see that the box with 1.5mm thickness has higher energy levels compared to 1.2mm one.This is due to the thickness which provides the extra mass and thus higher momentum than the 1.2mm one.
RESULT:
Thus the given simulation for the crashbox has been completed and the results have been recorded.