Fatigue assessment of hydraulic cylinder housings of earth moving machines considering variable amplitude loading

In this research work, an assessment of hydraulic cylinder housing is presented. First, the in-service loads are measured for the three most fatigue-stressed cylinders of an earth moving machine: boom, arm and bucket cylinders. Fatigue crack propagation tests were then carried out, on C(T) specimens extracted from cylinders, under both constant amplitude and service stress time histories. Finally, comparison between experimental outcomes and crack growth calculations carried out by means of both the Strip-Yield model and a simple “no interaction” model are presented.