Ansys Learning Forum Forums Discuss Simulation LS Dyna Ignore bulk and shear modulus in UMAT LS_DYNA input parameter? Reply To: Ignore bulk and shear modulus in UMAT LS_DYNA input parameter?

Andreas Koutras
Ansys Employee

Hello Tuan,

The bulk and shear moduli should be specified. 

From Appendix A of the Manual:

"all user-defined material models require bulk and shear moduli for transmitting boundaries, contact interfaces, rigid body constraints, and time-step calculations."