Method of calculating the resistance force upon an impact on a composite target

A kinematically possible velocity field allowing calculation of all the necessary integrals in quadratures and obtaining an analytical solution for the resistance force induced by impactor penetration into the target is constructed. The Saint-Venant model of a rigid-plastic body and the theorem on the upper bound of the limit load are used in solving the problem. The essence of the method applied is using the equilibrium equation in the form of the Lagrange equation. The kinematically possible velocity field allows obtaining an upper bound of the limit load, i.e., estimating the resistance force to impactor penetration.