Elasto-Plastic and Large Deflection Analysis of Thin Shells by the Flow Theory of Plasticity 770590

This is a subsequent report on a study of the sheet metal response subjected to impact loads. The mathematical model of thin shells employed in the previous report is used once again to model the sheet metal. Based upon nonlinear shell theory, the flow theory of plasticity, and the finite element technique, the equilibrium conditions in the incremental form at each nodal point are established. Step-by-step numerical integration is applied to solve these equations and an error control procedure is incorporated at every load level. A computer program has been written according to this formulation and development. It was checked by running two sample problems for which solutions exist in the literature and one problem whose solution was experimentally evaluated from a full size structure. In addition applications relative to finding the dent resistance and oil-canning deformations of sheet metal body components in an automotive structure are discussed.