Modeling of high velocity impact of spherical particles

A systematic analysis of a single copper particle impacting a semi-infinite copper substrate was carried out for initial impact velocities ranging between 100 m/s and 700 m/s by using the finite element method. Capability of and various issues related to: modeling in a Lagrangian reference frame; modeling using adaptive remeshing in an ALE reference frame; and, modeling considering material failure in a Lagrangian reference frame, are discussed. The Lagrangian approach with material failure is found effective in describing material behavior under high deformations and preventing excessive distortion of the mesh. It is found that at fast impact velocities the particle-substrate interface continuously undergoes shear failure as the particle penetrates into substrate. A lip which mostly contains failed material is formed as a result of localized deformation. Plastic deformation is confined to a small volume around the impact zone. Maximum strain is developed at the surface of particle and substrate. Compressive residual stresses are generated below the impact site after particle rebound, and higher impact velocities result in deeper compressive layers and somewhat larger stresses. A notable similarity in deformation patterns is observed between the impacts of 50 mu m and 5 mm particles. Smaller particles are found to behave slightly stiffer than larger particles because of the strain-rate effects. (C) 2011 Elsevier B.V. All rights reserved.