Quadratic and Cubic Transition Elements

Abstract : Based on the investigation of Barsoum, Henshell and Shaw, quarterpoint quadratic elements have been successfully used as crack tip elements in fracture mechanics. This concept of singular element was extended to cubic isoparametric elements. Recently it was discovered by Lynn and Ingraffea that under special configuration, transitional elements improve the accuracy of stress intensity factor computations. In this report, we have obtained the location of mid-side nodes of these transitional elements for the quadratic as well as cubic elements. The cubic transitional elements were used for the double-edge crack problem, and it was found that there was improvement in accuracy for a configuration which consisted only of singular and transitional elements. However, for a well laid out grid, the improvement was only marginal.