Hello i created a user material of a composite that is working fine in static steps, however, to be able to model progressive damage, i’d like to use it in a dynamic step…

Now i would like to use it in Dynamic explicit steps, is there any known limitation for user materials with dynamic explicit steps ?

Thank you for your help !

I don’t think it’s mentioned in the documentation and I haven’t seen any working analyses like that. Abaqus has separate subroutines for implicit and explicit solver (e.g. UMAT and VUMAT). But give it a try and let us know, it would be nice to have a confirmation if it’s possible in CalculiX.

Thank you for the link, i already went through that one. I am trying to find out just by using a umat containing linear elasticity. Actually what is stopping the calculation of moving forward is the calculation of the stable time increment.

What if you add dummy element(s) with built-in elasticity ? Or even use direct incrementation (normally not recommended) ?

Hello @Calc_em , thank you for those hints. Indeed i used the DIRECT keyword & the stable time increment computed with the built-in linear elastic orthotropic material, and it the simulation runs. I agree with you that putting somewhere a built in linear elastic element should do the trick, i’ll try it as well and post the outcome here. Note that I could not find in the source code where the increment is computed based on the density and elastic properties.

It seems to be this file: CalculiX/src/calcstabletimeincvol.f at master · Dhondtguido/CalculiX · GitHub

oh thanks, indeed with that name i should have found it i’ll have a look !