Describing necking/strain softnening in solids4FOAM

Shibi · April 2, 2021, 13:48

Hello to all,

I would like to know if it is possible to describe strain softening in solids4Foam.

The material I am using as some strain softening after yield (not has pronounced as in the image above) followed by strain hardening.
I would like to input this behavior in solids4Foam. Can I just place the true stress- true strain curve in a file like in the neckingBar tutorial?

What is the best approach to model this behavior?

If I model strain hardening, does the first value of hardening need to be higher than the yield stress?

Best Regards!

bigphil · November 24, 2021, 12:06

Hi,

Yes you can just replace the true yield stress- true plastic strain curve, although softening may lead to unstable localisations and possibly mesh sensitivity. The current approach may be OK for your purpose, otherwise special procedures may be required to avoid mesh sensitivity e.g. https://www.researchgate.net/publica...7abAKQk0h9zPFQ.

Philip

April 2, 2021, 13:48	Describing necking/strain softnening in solids4FOAM	#1
Shibi Member Join Date: Feb 2020 Posts: 90 Rep Power: 6	Hello to all, I would like to know if it is possible to describe strain softening in solids4Foam. The material I am using as some strain softening after yield (not has pronounced as in the image above) followed by strain hardening. I would like to input this behavior in solids4Foam. Can I just place the true stress- true strain curve in a file like in the neckingBar tutorial? What is the best approach to model this behavior? If I model strain hardening, does the first value of hardening need to be higher than the yield stress? Best Regards!

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November 24, 2021, 12:06		#2
bigphil Super Moderator Philip Cardiff Join Date: Mar 2009 Location: Dublin, Ireland Posts: 1,089 Rep Power: 34	Hi, Yes you can just replace the true yield stress- true plastic strain curve, although softening may lead to unstable localisations and possibly mesh sensitivity. The current approach may be OK for your purpose, otherwise special procedures may be required to avoid mesh sensitivity e.g. https://www.researchgate.net/publica...7abAKQk0h9zPFQ. Philip