Abstract
A hybrid stress finite element procedure for the solution of bending stress intensity factors of a plate with a throughβtheβthickness crack is presented. Reissner's sixthβorder plate theory including the effects of transverse shear deformation is used. The dominant singular crack tip stress field is embedded in the crack tip singular elements and only regular polynomial functions are assumed in the far field elements. The stress intensity factors can be calculated directly from the crack tip singular stress solution functions. The effects of the plate thickness, the ratio between the crack size and the inplane dimension of the plate, and the singular element size on the stress intensity factor solution are investigated.
The effects of the explicit enforcement of tractionβfree conditions along crack surfaces, which are the natural boundary conditions in the present hybrid stress finite element model, are also investigated. The numerical results of bending of a plate with a straight central crack compare favourably with analytical solutions. It is also found that the explicit enforcement of tractionβfree conditions along crack surfaces is mandatory to obtain meaningful results for the Mode I type of bending stress intensity factor.