Which material law to assign to nanoparticles in RADIOSS?

Hello,

I want to assign the nanoparticles as solid body and solid body as SPH particles to track the motion of particles during the process. For the current process, we are going to have two semisolid (2 different nanoparticles) and to track the motion of each nanoparticles by SPH formulation by giving different color during simulation. But, I am not getting which material law I need to apply for nanoparticles.

Moreover, my process involves high plastic deformation hence constraint to use RADIOSS.

Hope to see your reply.