Unitless FE solvers

[Disla]

Hi rsmith and thanks for comment on this,

This comes from a previous post that was experiencing some convergence issues.

Pre-stretch membrane simulation error

Nice area of research!!. I find some discrepancies on the data and your model. Your final thickness is 2mm in the pres-stretch step1. That shows some issue in the compressibility. It should be 0.16mm or close as advanced on the paper. [screenshot.292] Your analysis should consider material nonlinearity (Mooney Rivlin) not only geometric nonlinearity. Hint to check the accuracy of your results: This is a Pure Biaxial Stretch (in cylindrical coordinates). Principal Stress 1 and 2 must be e…

If D=0.8237E-05 has [mm2/N] units in our particular case would deliver a Posson Ratio of .5 with the corresponding convergence issues.

If D=0.8237E-05 has [m2/N] ,as I think , that value is not enought for the large stretch ratios involved. (Jacobian ends up at 1.42).

I think units should be shown or maybe better :

*WARNING reading *HYPERELASTIC: default value was used (Poisson coefficient of 0.475)