Weight functions and strip-yield model analysis for three collinear cracks

Multiple site damage imposes severe threat to aircraft structural integrity. In this paper, fracture mechanics analyses for multiple collinear cracks using the weight function method are presented. Weight functions for general collinear cracks are derived, which are found significantly different from those for single crack cases. To demonstrate the approach, exact weight functions for three collinear cracks are determined. By using the derived exact weight functions, accurate stress intensity factors, crack opening profiles and strip-yield model solutions of plastic zone sizes and crack tip opening displacements for three equal/unequal length collinear cracks are obtained with high efficiency.

► A weight function method for general collinear cracks is established.
► Exact weight functions for three symmetrical collinear cracks are presented.
► Exact stress intensity factors and crack opening displacements can be obtained by the present method.
► The plastic zone sizes and crack opening displacements for the strip yield model of the three cracks are presented.