Effect of non-planar cracks with islands of contact on the elastic properties of materials

The contribution of a spherical cap crack having an "island" of contact between its faces into elastic compliance of a material is analyzed. Vector of the displacement discontinuity at the crack faces in response to remotely applied stress is calculated using the mesh free technique based on the solution approximation by Gaussian functions. The result is used to construct the compliance contribution tensor of this crack as a function of the island position and extent of non-flatness of the crack. This tensor is orthotropic and the two mentioned factors produce complex combined effect. To study these effects, simple analytical approximation for the obtained numerical result is proposed. The effect of position of the contact is substantial even for planar cracks and it becomes much stronger for non-planar ones; the effect of the size of the contact is generally similar to that for planar cracks. Moderately non-planar cracks may be approximated by planar ones with acceptable accuracy. (C) 2020 ElsevierLtd. Allrightsreserved.