Feathering Cracks Formation At Single Wing Crack Evolution

Wing crack formation was studied in a compression test system on PMMA and gypsum. Wing cracks are the tensile cracks starting in the area close to the top of the preexisting defect - an inclined initial cut. The crack growth is followed by relative shear motion between the surfaces of the initial defect. The shear zone was studied separately and a set of feathering cracks developed. The scenarios of complex wing-crack systems development are discussed.