A two-dimensional boundary element method for analysis of closed or pa
rtially closed cracks under normal and frictional forces is developed.
The single domain dual formulation is used. As a contact problem is n
on-linear due to the friction phenomena at the crack interface and als
o because of the boundary conditions which may change during the loadi
ng, it is formulated in an incremental and iterative fashion. The stre
ss intensity factors are calculated with the J-integral method. Also c
rack growth is considered. Several benchmark cases have been analysed
to verify the results given by the method. The stress intensity factor
s and crack paths calculated are similar to those given in the literat
ure. (C) 1997 by John Wiley & Sons, Ltd.