Biaxial load effects on the crack border elastic strain energy and strain energy rate

In a previous paper it was shown that the singular expressions for the elastic stress and displacements in the border region of a line crack are inadequate, generally speaking. This is nowhere more clearly demonstrated than for the case of the infinite sheet with a flat central crack, biaxially loaded along its outer boundaries. For this particular problem, the entire effect of the load applied parallel to the plane of the crack shows up in the generally discarded second (non-singular) terms of the series representations for the stresses and displacements. Omission of these contributions is, in effect, equivalent to denying the presence of the boundary load applied parallel to the crack and, consequently, leads to prediction of results at variance with experimental data.

In this paper we continue with further discussion of the same problem, focusing attention on the fact that the local elastic strain energy density and strain energy rate depend significantly on the biaxiality of the applied load.