A higher order displacement discontinuity method for three-dimensional elastostatic problems

The three-dimensional constant strength displacement discontinuity method, as presented by Salamon, is based on a solution which expresses field stresses and displacements due to constant normal and shear displacement discontinuities over an elemental area in an elastic body. Following a two-dimensional development, a new three-dimensional higher order displacement discontinuity element is presented in this paper. The new higher order (bi-quadratic) approach is based on the use of nine collocation points spread over a nine element patch, centered at the source element. In addition, special crack tip element logic is developed which allows a more accurate calculation of the stress field near the crack tip.