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Crushing analysis of composites

Hi
I am trying to model a pin-loaded test of composites under high-speed loading with Radioss. I used MATLAW25 and Hashin failure criteria to capture progressive damage. However, after an initial peak in the load, my resultant reaction forces fall to almost 0 instantly, then increase again to a lower peak and then fall back to 0. But for crushing the force while oscillating, it should gradually decrease to 0. I'm not sure why this is not happening in my model. I have attached the files to this. Any help on this would be greatly appreciated.

Fresh.hm

Fresh_0000.rad

Fresh_0001.rad

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Marina_Lima

Hi,
The peaks observed in the rigid body reaction are due to the contact between the pin and the plate. As elements are deleted upon reaching the failure criteria, the force slightly increases until the pin contacts the next element. This behavior is expected.
To mitigate these peaks, I recommend adjusting the value of Tau_max. According to the documentation, a value 10 times the time step is suggested (Comment 5).
https://help.altair.com/hwsolvers/rad/topics/solvers/rad/fail_hashin_starter_r.htm#fail_hashin_starter_r__fail_hashin_starter_r_fn_nwg_hk5_xz

Best regards,
Marina Lima

ShreyaRiadeepya

Hi,

I understand the peaks but my question is why does the force fall to 0 after a peak immediately? By this logic if I set a Tau max 10 times the time step then my pin should get in contact with the next set of elements almost immediately. It doesn’t explain why it goes to 0 after a peak. Or is there some other reason for the same?