A semi-infinite-crack model for determining mode I stress intensity factors using crack surface displacements

Abstract

A semi-infinite-crack model is used to supplement the conic section simulation method for determining stress intensity factors of finite cracked bodies under mode I loadings. The actual displaced crack surface profile is found by finite element analysis. For each crack surface segment between two neighbouring nodes, a set of model parameters is found by using the displacements of these two nodes. A stress intensity factor estimate is then calculated from the closed-form formula associated with the model. It is found that near-tip crack surface displacements produce model parameters that are sufficient for quantifying the stress intensity factor. The semiinfinite-crack model can be used either as a stand alone model or in conjunction with the ellipse simulation procedure to form a systematic approach. It is shown that this model can be applied to different geometries and loadings with excellent accuracy.