Analysis of the J-integral was made by using the finite element method for cracks emanated symmetrically from transverse ends of an elliptical hole in a plate which was subjected to uniaxial tension, biaxial load or hydrostatic pressure. The power-law stress and strain relation was assumed in the analysis. The main conclusions obtained are as follows:
(1) Under uniaxial tension, the J value for the present problem increases rapidly with an increase in the emanated crack length and approaches to that for a center-cracked plate (CCP) with the same gross crack length, when the elliptical hole is long in the transverse direction. For elliptical holes long in the axial direction, however, the J values increase rather slowly with increasing crack length and tend to give much higher values than that for the CCP at large crack lengths.
(2) Under biaxial load, the J values of axially long elliptical holes become smaller when the transverse tensile load is applied, and larger when the transverse load is in compression. For transversely long elliptical holes, the J values show minimum values at certain tensile loads close to the equi-biaxial tensile load.
(3) When hydrostatic pressure is applied on the surface of both the hole and the crack, the J values increase slowly with an increase in the emanated crack length because of the mechanical effect similar to that under the biaxial tension.
(4) A simple formula for J-estimation, which uses the load and the load point displacement, was found useful if the crack was“deep”. When a notch opening displacement was utilized in place of the load point displacement, the effective range of the formula was very much extended to a shorter crack length.
