Well Multiple Responses make it Difficult to work out, ok I am followign the order of posting. n1) SPH is the best way to simulate Material failure, but it need better formulation to capture the deformation at such speeds, generally use MLS or default type.In general, use LSDYNA SPH section to impliment your model as it is more stable in my expereince. Usign the body Interactions ( nodes to surface) -> frictional is recommended. nGenerally, HVI problems needs control on the time step and its factor, try using 0.85 and keep the stef size to be small to capture the interaction. Always use some kind of erosion criteria like EPS or (D1,D2,D3,D4) to simulate the damage. Use JH1,JH2 or JC(4D) models for brittle-> Papers are best source for these model. Smaller the prticel size better the results as with the Mesh convergence. Try these and comment down for futher support. nCheers, nRamnn