Peter Yip

Hi Jim,

My apologies. From the Implementation of the Johnson-Holmquist I (JH-2) Constitutive Model Into DYNA3D by George A. Gazonas paper, it explicitly says in the algorithm procedure that they compute the equivalent plastic strain rate which I assumed is the traditional formulation and verified with other papers in the resources you provided. The LS-DYNA Support link here (, still confuses me because I am sure if you did take a radial return approach, you can have it compute the equivalent plastic strain increment and then use that to update the equivalent plastic strain at each integration cycle. Do you have any input as to know which one LS-DYNA chooses and when/why?