Hello there,

I was trying to do a nonlinear simulation with Polyurethane material with Model Mooney Rivlin. I got the S-S curve data(uniaxial, biaxial and planar raw data) from Matereality, but no matter how I tweak the setup, the error message prompts up after I hit Run.

Does anyone know how to fix this error? Could the material data be possibly incorrect?

Thanks.

I recommend these SOLIDWORKS Simulation Help topics as a starting point:

2020 SOLIDWORKS Help - Defining Stress-Strain Curves

2020 SOLIDWORKS Help - Recommendations for Hyperelastic Materials

In particular, note that the expected input for test curves for Hyperelastic material models (like Mooney-Rivlin) is

Stretch Ratio, not Strain. Some cases where the "A+B < 0" message appears are due to Strain being used in the material test curve inputs instead of Stretch Ratio. Also, be aware that Stress in the input test curves is expected to be Engineering Stress, while Stress result output from SOLIDWORKS Simulation will be True Stress.Please refer to the following KB solutions for additional information - they contain some attachments which may be very useful, including a SOLIDWORKS document example that uses the 'Use curve data to compute material constants' option:

S-034890: "How do I calculate Mooney-Rivlin constants from test curves in SOLIDWORKS® Simulation?"S-019324: "Stress and Strain Equations"And if this is urgent, please also contact your SOLIDWORKS Value Added Reseller (VAR) for assistance.