Unexpected Force-Displacement plot

MartinaC
MartinaC Altair Community Member
edited October 2020 in Community Q&A

Hi everyone,

I am simulating a tensile test of a homogeneous isotropic material, according to the coupon bar example in 'Introduction of Non Linear Finite Element Analysis using Optistruct'.

I imported a different material and the coupon bar geometry is a bit different. I do not understand why the numerical force -displacement curve decreases after the yielding point, while, for example in the ebook, it follows the input trend.

 

I though the possible problems could be the definition of the true stress-strain curve, or the NLQS parameters NINC and NLOUT, the chosen finite elements (tetrahedral; I used this type because I have to calibrate the material to perform analyses on more complex geometries).

 

Can anyone find the problem?

 

I attach the .fem file (ModelB_prova_NLQS).

In additiion I attach a model that behaves as expected (Model2_surf_prova10_NLQS

Unable to find an attachment - read this blog

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