Impact Induced Stresses, Strains, and Delaminations in Composite Plates

Abstract

A method is presented for calculating the locations and sizes of delaminations which oc cur in a rectangular, fiber reinforced composite plate sujected to non-penetrating (low velocity) impact of a solid object. The plate may be simply supported or clamped along its edges. In-plane loads or in-plane strains may be imposed on the plate during the im pact. The method includes two steps. First, the stresses and strains in the plate are calculated by a three-dimensional, transient finite element method using 8-node brick ele ments with incompatible modes. Second, the locations, lengths, and widths of delamina tions inside the plate are predicted by means of a proposed failure criterion, which is based on the concept of dimensional analysis. The finite element method and the failure criterion were implemented by a computer code which can be used to calculate the impactor posi tion and velocity, the displacements of the plate, the stresses and strains inside the plate during the impact, and the locations and dimensions of the delaminations after the impact. Parametric studies were performed to illustrate the information which can be generated by the computer code.