Crack tip finite elements are unnecessary

It is shown that a singularity occurs in isoparametric finite elements if the mid‐side nodes are moved sufficiently from their normal position. By choosing the mid‐side node positions on standard isoparametric elements so that the singularity occurs exactly at the corner of an element it is possible to obtain quite accurate solutions to the problem of determining the stress intensity at the tip of a crack. The solutions compare favourably with those obtained using some types of special crack tip elements, but are not as accurate as those given by a crack tip element based on the hybrid principle. However, the hybrid elements are more difficult to use.