The finite element method analysis for the stress intensity factors using a path independent Ê-integral formula

We present a new numerical path independent Ê-integral for calculating the stress intensity factors using a known auxiliary solution. The integral is path independent in the similar manner to the well known domain independent M-integral for calculating the stress intensity factors. The E-integral is, however, path independent even if the path contains any number of crack-tip and the integral may obtain the stress intensity factors at the onset of crack kinking by the path independent integral ; therefore, the integral path can be far from the crack-tip around which the numerical solution has noticeable error : The domain M-integral may not obtain the stress intensity factors at the onset of crack kinking and may be very difficult to obtain the stress intensity factors when there exist small cracks in the neighborhood of the crack-tip. For illustrative purposes, by using finite element method, numerical examples obtaining the stress intensity factors are presented for an extending straight crack and a kinking crack.