The inclusion of in-plane stresses in delamination criteria

A study of delamination is performed including strength of materials and fracture mechanics approaches with emphasis placed on methods of delamination prediction. Evidence is presented which supports the inclusion of the inplane stresses in addition to the interlaminar stress terms in delamination criteria. The delamination can be modeled as a resin rich region in between ply sets. The entire six component stress state in this resin layer is calculated through a finite element analysis and inputted into a new Modified Von Mises Delamination Criterion. This criterion builds onto previous criteria by including all six stress components. The MVMDC shows improved correlation to experimental data.