Abstract: Basic theory of displacement field in the blunt cracks is studied and a new displacement modelling of blunt crack is constructed. A finite element equation with a blunt crack is built, the new singular element at the end of a blunt crack is given and a new method for calculating stress intensity factors of blunt crack problems is presented. Solutions obtained with present method are good in agreement with those of theoretical solutions. With the different selections of the Gauss's points and structural dimensions, the calculating results with the present method are stable, reliable and highly accurate. The present method is easy to use in practical program operation. Numerical examples are given to illustrate the validity of the present method.

Key words: stress intensity factor, singular element, blunt crack, finite element method, displacement