Propagation of delamination in composite materials with isogeometric continuum shell elements

A continuum shell element based on the isogeometric analysis concept is extended to model propagating delaminations that can occur in composite materials and structures. The interpolation in the thickness direction is carried out using a quadratic B-spline, and delamination is modelled by a double-knot insertion to reduce the inter-layer continuity. Within the discontinuity, the traction is derived from the relative displacement between the layers by a cohesive relation. A range of examples, including delamination propagation in straight and curved planes and buckling-delamination, illustrate the versatility and the potential of the approach.