Progressive interfacial damage and failure in laminated shells subjected to blast

The presentation deals with the problem of damage progression and failure of laminated cylindrical shells subjected to blast loading. Systems where damage is due to the initiation/propagation of delaminations and intra-layer cracks and fiber failure are considered. A mechanical model is formulated based on a discrete layer approach and nonlinear fracture mechanics concepts. The shell is modeled as an assemblage of curved layers, or sub-shells, joined by cohesive/contact-type interfaces. The kinematic fields in each layer are described by first order shear deformation shell theory, which accounts for shear deformations, translational and rotary inertia. The shell is subjected to distributed pressure pulses, such as those resulting from a typical underwater blast. The problem of a long cylinder subjected to an asymmetric pressure load (side-on explosion) under plane strain conditions parallel to the longitudinal axis of the shell will be examined first to investigate the effects of geometrical/material properties, loading conditions and pre-existing damage on the mechanical response and final failure. Preliminary results of the work, for quasi static loading conditions, will be presented at the meeting.