APPROXIMATE CONSTRUCTION OF A WEIGHT FUNCTION FOR QUARTER-ELLIPTIC, SEMIELLIPTIC AND ELLIPTIC CRACKS SUBJECTED TO NORMAL STRESSES

Asymptotic behaviour of weight functions has been analysed for model c racks in the shape of an ellipse or part of an ellipse. For internal p oints of a contour, a well known asymptotic solution is used for a sem i-infinite crack with a straight front. An analytical description is s uggested for weight function behaviour at the points which are near th e intersection of the crack front and the free surface of a body. The general method of approximate construction of a point weight function has been proposed. This method uses the asymptotic behaviour of the we ight function itself. To use this method for a given crack, one should know the stress intensity factor K-1 at any distribution of the crack surface load. The comparison of K-1 calculated using finite element m ethods and the proposed method at other load distributions shows the h igh efficiency of the proposed method.