ElasticPP gap material causing errors

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abira
Posts: 33
Joined: Mon Feb 03, 2020 10:26 pm

ElasticPP gap material causing errors

Post by abira » Mon Nov 28, 2022 2:26 am

Hi,

I am using elasticPP gap material for two node link element to model a gap spring. I get the following error:
ProfileSPDLinDirectSolver::solve() - aii < 0 (i, aii): (74, 0)
Is elasticPP material only meant to be used for zero length elements or am I making some mistake?

Thanks
Abira Rather

mhscott
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Joined: Tue Jul 06, 2004 3:38 pm
Location: Corvallis, Oregon USA
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Re: ElasticPP gap material causing errors

Post by mhscott » Mon Nov 28, 2022 2:39 am

The material is not meant for any particular element. You have a singular stiffness matrix. You can add another material of low stiffness to the twoNodeLink.

abira
Posts: 33
Joined: Mon Feb 03, 2020 10:26 pm

Re: ElasticPP gap material causing errors

Post by abira » Mon Nov 28, 2022 3:00 am

Thanks Prof. for the answer. If I change nothing else in my model other than the material for the twoNodeLink element, I get no errors. If I change the value of gap to 0.0 for the elasticPP gap, that also solves the error. Maybe using the gap material in series with another material will help.

Thanks

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