New method for computing fatigue life based on stochastic modeling of multi-crack propagation

Aim.The otherwise excellent stochastic modeling of multi-crack propagation brings unfortunately great difficulty in computation. We now present a new method that we believe can overcome this computational difficulty to a certain extent. In the full paper, we use Sections 1 and 2 to explain our method in some detail. Essentially in Sections 1 and 2, we do three things: (1) using the recursion relations we derive, we solve the approximate eq.(3), which is the new approximate stochastic model of multi-crack propagation, to compute the lengths of cracks under cyclic loading; (2) we propose the variable interval method to simplify the computation while retaining acceptable precision of fatigue life; (3) we define the two types of factor of influence and obtain the recursion relations as expressed by eq.(5). To verify the rationality of our method, we give as numerical example the panel with finite breadth and collinear holes under evenly distributed loading. The computed results, given in Table 1 in the full paper, show preliminarily that the fatigue life of the multi-crack panel decreases with each increasing stochastic variable provided that the other two stochastic variables are kept unchanged.