An Approximate Analysis of Steady State Axisymmetric Deformations of Viscoplastic Targets

Steady state axisymmetric deformations of a viscoplastic target being penetrated by a rigid cylindrical penetrator with a hemispherical nose are analyzed. The presumed kinematically admissible velocity field satisfies all of the boundary conditions on the target/penetrator interface, and also the balance of mass. The unknown parameters appearing in the admissible velocity field are found by minimizing the error in satisfying the balance of linear momentum. The solution so obtained is found to be very close to the finite element solution of the problem. An advantage of the present technique is the enormous savings in the computational effort and resources required to analyze the problem.