Stress intensity factor and energy release rate of externally pressurized thick cross-ply (very) long cylindrical shells with low-hardening transverse shear modulus nonlinearity

Combined effects of modal imperfections, transverse shear/normal deformation along with the nonlinear hypo-elastic transverse shear (GTT) material property on the emergence of interlaminar shear crippling type instability modes, related to the localization (onset of deformation softening), delocalization (onset of deformation hardening) and propagation of mode II compression fracture/damage, in thick imperfect cross-ply very long cylindrical shells under applied hydrostatic pressure, are investigated. The primary accomplishment is the (hitherto-unavailable) computation of the layer-wise mode II fracture toughness, fracture energy and kink crack band-width, under hydrostatic compression, from a nonlinear Finite Element Analysis (FEA), using Maxwell's construction and Griffith's energy balance approach.