peridynamics EPS / computational problem


I am using EPS method for my project but I have a kind of computational problem.Indeed,I have illogical values at the end of my simulation. In the joined file, we can see on the unloading curve than it doesn´t follow the loading curve though it´s an elastic part. I tried to reduce largely time step in vain but I succeed in reducing this computational problem by increasing the yield stress. However, this computational exists still as we can see it on the joined file.

Do you have explanations to this problem ? Or maybe solution to solve it ?

Best regards

Simon Bourreau

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Maybe Rahman can comment. But in general,
“why didn’t my simulation do what
I expect” is not an easy Q to answer.


besides timestep size and yield stress you may try changing the critical bond damage (s00) and alpha too. this could help. always visualize your output when you see some illogical data (i.e. nan). at some point most likely the system is becoming unstable.

I already tried to change s00 and alpha with a very large range of value without success.
But I noticed while the stress became illogical, temperature strongly increased.
Normally, temperature isn´t really important in peridynamics but maybe, there is a link with this illogical stress.

What is weird too is when I increase yield stress, breakage doesn´t happen for stress higher than in previous simulation with a yield stress lower.