Jim Day
Ansys Employee
Hyperelastic materials and SPH typically don’t go together very well. SPH suffers from tensile instability, which means the material will have a tendency to break apart instead of deforming in tension. And as Ram mentioned, dynamat (based on information at the beginning of the *MAT section of the LS-DYNA User's Manual) indicates that SPH can't be used for MAT_295. If you're intent on using MAT_295, you could instead try EFG or SPG.