Optimized algorithm selection and parameter identification procedure for modeling projectile penetration into UHPC target with material point method and Kong-Fang model

When modeling rigid-projectile penetration into a concrete target with the material point method (MPM), multiple sources of error contaminate the results and sometimes promote non-physical behavior. This paper aims at minimizing the numerical error through an optimized algorithm selection and parameter identification procedure. First, the numerical errors originating from different MPM algorithms are compared in detail using three joint criteria: energy conservation, displacement response, and interpenetration of material particles at the contact surface. Based on these criteria, optimized integration scheme, contact parameter, spatial discretization, and time-step scaling factor are recommended for producing physically reliable results. Using the optimized MPM algorithm, the Kong–Fang model is calibrated against rigid-projectile penetration tests on UHPC. The analysis reveals how damage evolution governs crater formation and demonstrates that crater radius can resolve the compensation between the strength parameter and damage parameter that is obscured by DOP. The calibrated model accurately reproduces both penetration depth and crater size.