Analysis of progressive failure in composites

An incremental failure accumulation technique is presented for angle-ply, cross-ply and uniaxial composite laminates. Piecewise smooth failure criteria that distinguish between the failure modes are implemented in a finite element analysis with shear deformable elements. For each load increment, these criteria are checked within each lamina. As failure is detected, the material properties of the lamina are modified. Equilibrium iterations are performed before incrementing the load to track further damage in the laminate and, finally, the ultimate failure of the laminate. This technique of progressive failure is illustrated for uniaxial tension and four-point bending problems.