RADIOSS explicit simulation problem

Nahid3007
Nahid3007 Altair Community Member
edited October 2020 in Community Q&A

Hello community,

 

 

I have a problem in RADIOSS with an explicit simulation of a hydro bush where I try to find the basic stiffness of the bush.

 

 

I ran the simulation with the original model and the simulation seems to never terminate because the time step drops to a very small value and the run time is increasing.

 

 

So I decided to simplify the problem I am concerning with and try to solve the problem (more or less by try and error at the moment).

 

In FIGURE_1 (attached) I have run three simulations with my simplified models.

 

 

The simulation in the figure on the left hand side is really close to the problem I have with the hydro bush (more or less).

It is a rubber to rubber material impact. So I have used MAT42 (hyperelastic material model) and I have used the contact TYPE 7.

The cylindrical material is being pushed with a concentrated force to the wall for the impact. The total run time is 1 second and I have used the DT/NODA/CST/0 to increase DT.

The first simulation in the figure on the left hand side was killed because it has reached the limit for its total mass error and the energy error.

 

 

The second simulation in the figure in the middle was slightly chanced but with no changes in the engine file. Here, the run terminates (without issues) but the value for the energy error was still high and as you can see there are some distorted elements.

 

 

In the last simulation in the figure on the right hand side I made the wall thicker and still did not change the commands in the engine file. Here, the run terminates properly and the energy error is also good. I am not allowed to change the model properties but this is the result I want to achieve with the simulation one and two.

 

 

How can I improve simulation one and two? Could it be a problem in the contact definition or some mistakes in the property definition? I will attach the starter and engine file as well as the engine OUT file of simulation one and two.  

 

 

 I would be really great if I can get some useful hints on how to improve the problem, because I am really new to RADIOSS.

 

 

Thank you very much in advance.

 

<?xml version="1.0" encoding="UTF-8"?>FIGURE_1.jpg

 

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