chang failure in LAW 25

ke li

Hallo, I try to simulate a compress test with Material law 25. I add the failure_chang model to define the compressive strength in two directions. But it did not work. When I change the compressive strength values, the result (max. Force) is always the same. please someone tell me, where is the Error. 

another question。

When I only change the compressive velocity, the result  (max. Force) will be changed. This confuses me.

LAW25_compress_0000.rad

LAW25_compress_0001.rad

Rogerio Nakano_21179

Hi

I think that the load is the same because is the load the structure buckle.

if you remove the failure, it will not have elements failing, but still the buckle load is same.

 

For compression test, in the general the free length is shorter, about 1/2in, so that the buckle is less prone.

 

It is recommended to set the Ishell=12 to the composite element formulation.

And if using /FAIL/CHANG, set the Tau value to about 10x of the time step

Please refer to the comment 7 of the documentation of /FAIL/CHANG.

https://2021.help.altair.com/2021/hwsolvers/rad/topics/solvers/rad/fail_chang_starter_r.htm

 

I hope this is helpful.

Regards