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NONLINEAR STATICS REMOVING STIFFNESS FROM ELEMENT AFTER REACHED CERTAIN VALUE OF STRESS

Creator
Creator

Hi,

I am doing a nonlinear static analysis with NX Nastran. I would like to know if there is a way to remove the stiffness of all the element as soon as they reach a certain level of stress.

Thank you

3 REPLIES

Re: NONLINEAR STATICS REMOVING STIFFNESS FROM ELEMENT AFTER REACHED CERTAIN VALUE OF STRESS

Siemens Phenom Siemens Phenom
Siemens Phenom

This can be done in the advanced nonlinear solution (SOL 601) for multilinear plastic materials by setting XTCURVE=0 on NXSTRAT.

 

The default behavior (XTCURVE=1) extends the stress-strain curve via extrapolation. If XTCURVE=0, the curve is not extended and any integration point with a strain greater than the last point on the stress-strain curve is considered to be ruptured and the associated element is removed from the solution.

 

https://docs.plm.automation.siemens.com/tdoc/nxnastran/11/help#uid:index_QRG:id511666:id508571

Re: NONLINEAR STATICS REMOVING STIFFNESS FROM ELEMENT AFTER REACHED CERTAIN VALUE OF STRESS

Creator
Creator

Thanks. I have read that it is valid only for multilinear-plastic material model. Is there is a way to use a straight line for the stress-strain curve? I would like the stiffness do not change until rupture.

Re: NONLINEAR STATICS REMOVING STIFFNESS FROM ELEMENT AFTER REACHED CERTAIN VALUE OF STRESS

Siemens Phenom Siemens Phenom
Siemens Phenom

The points in the stress-strain data could form a "nearly" straight line. They just have to satisfy the conditions given in SOL 601 Remark 11 for MATS1

 

https://docs.plm.automation.siemens.com/tdoc/nxnastran/11/help#uid:index_QRG:id511666:id508406