Hyper-elastic material may become unstable, message for Mooney-Rivlin model
I am trying to use my experimental data for vulcanized natural rubber for some finite element simulation in ANSYS, and noticed that the closest fit is given by Mooney-Rivlin. But unfortunately, this material model gives the warning mentioned in the subject prior to solving, and the process terminates with error in element formulation.
Other material models like Neo-Hookean and Ogden dont seem to be providing a good fit with the experimental stress-strain curve, but theres no such warning or element formulation error for those.
Im simply using a rectangular area with Plane Stress w/Thk element real constant specified, plus the aforementioned curve fitting of my experimental curve.
Can you show figures with the experimental stress-strain curve(s) that you have?
I was able to curve-fit by unchecking the Use Normalized Error checkbox in the curve-ftting dialog in ANSYS. Im not exactly sure what purpose it serves, but the fits are good now.
Currently I dont have access to the images. I will share as soon as availble.