COMPUTATION OF MEMBRANE AND BENDING STRESS INTENSITY FACTORS FOR THIN, CRACKED PLATES

The crack tip stress fields for prate bending and membrane loading pro blems are reviewed and the four stress intensity factors that determin e these fields are defined. These four stress intensity factors arise from use of Kirchhoff plate theory to account for the bending loads an d two dimensional plane stress elasticity to account for the membrane loads. The energy release rate is related to the stress intensity fact ors and to the stress resultants of plate theory. Virtual crack extens ion, nodal release and modified crack closure integral methods are dis cussed for computing components of the energy release rate from finite element analyses of cracked plates. Sample computations of stress int ensity factors for single and mixed mode cases are presented for a cra ck in an infinite plate. Sample computations of stress intensity facto rs for a double edge notched tension-torsion test specimen are given a s well.