Singularities at the Tip of a Crack Normal to the Interface of an Anisotropic Layered Composite

摘要

The order of stress singularities at the tip of a crack which is normal to and ends at an interface between two anisotropic elastic layers in a composite is studied. Assuming that the stress singularities have the form equations are derived for determining the order of singularities K. If the materials on both sides of the interface are identical, K = 1/2 is a root of multiplicity three each of which can be identified with the singularity due to, respectively, a symmetric tensile stress applied at infinity, an antisymmetric plane shear stress and an antiplane shear stress applied at infinity. When the materials on both sides of the interface are not the same, there are in general three distinct roots for K. Numerical examples for a typical high modulus graphite/epoxy and for a special T300/5208 graphite/epoxy show that k has three positive roots all of which are close to 1/2 for most combinations of ply-angles in the two materials.