Finite elements for determination of crack tip elastic stress intensity factors

To compute stress intensity factor Ksub(I) which describes the spatial distribution of stresses around the crack tip, 8-noded quadrilateral and degenerated triangular elements have been developed. These have been used to solve the sample problems and results have been presented. Necessary modifications suggested in the literature were done to the troublesome shape function. However, during the investigation it was found that the elements get warped under these modifications. Further to avoid this warping, modifications have been suggested in this report to the shape functions of the corner nodes of side opposite to crack tip. Results obtained with these modifications have been also presented. (author)