Assignment 3

OBJECTIVE: To compare the results of a crassh beam file using Hypermesh Radioss with the given parameters changes.

SOFTWARE USED: Hypermesh 2019 (RADIOSS)

PROCEDURE:

1. We first Import the run file to the radioss block by going to import and then importing the solver deck.

2. After we import using the standard values we go to the analysis toolbar and click on radioss to proceed with the base simulation.

This above is the imported model after we imported the files through solver deck.

3. Now we choose the run file in radioss block and click on radioss button to initiate the simulation.

By doing this we have initiated a sequeence where Radioss will implement simulation for the givevn time steps and animation functions according to the user.

For the initial case the time was 60 ms.

The results of the simulation are as follows:

In the above image we can see the displacement contour and the right side displays the RWall forces. These forces are generally those that act normally or tangentially on the wall while the crash is taking place.

For the first simulation we can see that the tangent force and normal force are differentiated for the most of the time in this simulation.

Hourglass Energy Plot For first Simulation

Plastic Strain plot For simulatiuon 1

For the second simulation these were the changes that were made

Parameters		Comment
Ishell =24		QEPH 4 nodes shells are best combination of cost and accuracy.
Ismstr=2		Full geometric nonlinearities (default)with possible small strain formulation activation in RADIOSS Engine.
Ish3n=2		Standard 3 noded shell (C0)with modification for large rotation(default)
N=5		Number of integration points set to 5 for accuracy bending.
Ithick=1		Thickness change is taken into account for accuracy.
Iplas=1		Iterative plasticity for good accuracy.

Apart from the the animation time step was changed to 25 as a minimum and the time for the simulation waas changed to 55ms.

Runtime 55 ms

The results are as follows.

We can see here that the internal energy and kinetic energy start at different areas of the graph. This is because the inernal energy starts with 0 but when the body hits the wall the internal molecules try to accomodate and thus we get a spike in energy. Similarly at start the kinetic energy is high due to the Velocity of the moving body but reduces as the body undergoes the simulation.

The above image shows the wall forces of the model for the 2nd simulation. As we can see that the forces are much more random as compared to the previous simulation. We can also find a critical point where the forces are equal to each other at a certain point which is completely different from the first simulation.

Velocity contour of the Simulation

CONCLUTION:

We can conclude that the result with the proper parameters is far more generalised than the one where we just ran the raw simulation without giving the elemental parameters.

The link for the Files is : https://drive.google.com/open?id=1zPGgrEnhnV8VYNqWP_mXE_5xwaxXIcOy