Negative Stress Values with Incompressible Material

[catrueeb]

I am doing an analysis involving an incompressible Hyperelastic Ogden material formulation. Setting D=0 in the model parameters should specify the model as incompressible. When checking the results, there are negative strain values and the negativ corresponding stress values under minimum principal stress and minimum principal strain. How can I understand negative stress for incompressible materials?

Regards,
Camill

 

[Mustaine3]

It usually shows that you material is unstable with the chosen coefficients in specific stress/strain regions. Use the material evaluation tool in A/CAE to check the stability. Or maybe it is also printed in the .dat or .msg of your analysis.

 

[rothers]

"incompressible" doesn't mean there are no compressive strains.

 

[Mustaine3]

Correct. My comment was meant for situations that show negative stresses for positive strains.

 

[IceBreakerSours]

Are you using a hybrid element?

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