Engineerng method of constructing a weight function for plane normal-separation cracks in three-dimensional bodies.

On the basis of an analysis of the known solutions for a circular and for a semiinfinite normal-separation crack with straight front in an infinite body we constructed, in analogy to the method of Burns and Oore, a weight function for elliptical cracks. Its use for finding the stress intensity factors K at the point of minimal curvature under conditions of uniform loading leads to a maximal error of 10%; at the point of minimal curvature of the crack front the error increases with decreasing ratio of the semiaxes of the ellipse. With the aid of this solution the weight function is found in bounded bodies with a quarter-elliptical, semielliptical, and elliptical crack. A comparison of the data obtained by this method with the values of K calculated by the finite-element method under nonuniform loading showed that the suggested method is very accurate. [ABSTRACT FROM AUTHOR]