Rapid determination of histories of SIF distributions along 3-D crack fronts of a plate subjected to thermal shock

The basic equation for the 3-D thermal weight function (TWF) method for Mode I is derived. Then, a novel technique, referred to as multiple virtual crack extension technique, is proposed to solve the basic equations in the 3-D TWF method. The coefficient matrix of the final system of equations is a triple-diagonal matrix and the values of the coefficients on the main diagonal are large. The system of equations has good numerical properties. The complex situations during thermal shock, in which the stress intensity factors (SIFs) vary dramatically along the crack fronts, can be numerically well simulated. The finite element implementation of the method in 3-D cases is presented. A plate model with various crack configurations and constraint conditions was solved. The results show that, the histories of SIF distributions along 3-D crack fronts are very complex. In order to understand the behavior of 3-D cracks correctly, it is necessary to calculate the histories in detail. The scheme is of very high efficiency and of good accuracy.