Simple, conservative criteria for buckling and delamination propagation inthe presence of stitching

The problem of delamination cracks in laminates that are bridged by stitche s is revisited. Analytical solutions for the critical strain for buckling o f a bridged, delaminated layer are extended to consider propagation of the delamination crack under in-plane compression in the limit that the crack i s long. Numerical estimates for common laminate parameters show that delami nations of interest will not be far from the long crack limit. Therefore, t he analytical results should be conservative but not wasteful design guides .