Modified Dugdale model for four collinear straight cracks with coalesced yield zones

A prelude to the problem of two collinear straight cracks has been considered in this paper. Multiple site damage problem of four cracks with coalesced yield zones under the influence of linear stress distribution is discussed. It is assume that the configuration of cracks considered in this paper is just before the formation of two equal straight cracks. Analytical expressions are obtained for stress intensity factors, crack tip opening displacements(CTODs) at each crack tip using complex variable method. A numerical study is carried out to compare the effects of linear stress distribution on the growth of yield zones for two different crack configurations. Some of the analytical expressions are compared with previously published works as a limiting case. Furthermore, results are compared with the solution of two equal collinear straight cracks under similar mechanical loading conditions.