Fatigue life prediction of the plates with an inclined surface crack

The angled crack problem has been given special attention in recent years by fracture mechanics investigators due to its close proximity to realistic conditions in engineering structures. In this paper, an investigation of fatigue crack propagation in rectangular aluminum alloy plates containing an inclined surface crack is presented. The inclined angle of the crack with respect to the axis of loading varied between 0° and 90°. During the fatigue tests, the growth of the fatigue crack was monitored using the AC potential drop technique. Based on the concept of the effective stress intensity factor range, (delta)K(eff) , an effective strain energy density factor range, (delta)S(eff) is proposed in the present study. The rate of fatigue crack propagation, db/dN, is then postulated to be a function of the effective stress intensity factor range, (delta)K(eff), and thus the effective strain energy density factor range, (delta)S(eff). Subsequently, this concept is applied to predict crack growth due to fatigue loads.