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Material curve longitudinal and transverse (thermoplastic Polymer)

Altair Forum User

Hello,

on your opinion, what kind of material formulation could be the best for the material described by the attached graph?

Considering we want to apply on the structure a static load case and the material is a Thermoplastic Polymer.

I'm using Optistruct solver

thank you

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Altair Forum User

Hi @Franz_M

What are all material properties you have?

If you just have linear properties and stress-strain curve, you can use MATS1 in OptiStruct to define material non-linearity and use NLSTAT analysis type.

Altair Forum User

The other given material properties values are:

image.png.7d5d8ffa45f7d3df76410b5649dc8458.png

I had to suppose 0.35 as poisson ratio, that is missing as you can see.

I tried to use MATS1, as you suggest, with 'non-linear quasi-static' as analisys type.

In this forum, I've seen in other similar topic, so on that base:

I have created a stress-stain curve as TABLES1, so that curve is the TID for MATS1.

In MATS1 card I have choosen 'PLASTIC' as Type and '0' as TYPSTRN.

In order to create the curve I had to modify the experimental curve to avoiding negative slope or increasing slope (else I obtained erros during the model RUN)

So the curve I could use is the green one in the follow graph:

image.png.1aab50cfd142cee188293c531bb7d047.png

I think this is the simpiest way to execute the analisys by an implicit code. Do you think it is correct?

I think material supplyer omitted the poisson ratio, because he gives tranversal values, are there a way to implement these values?

I hope I didn't make mistakes and the explanation shoul be clear

thank you