Cumulative Damage Analysis for Hydraulic Hoses

This paper illustrates how a linear cumulative damage analysis can be used to predict the fatigue life of hydraulic hose or hose assemblies subjected to variable amplitude pressure histories. The procedure is similar to that used for metal fatigue. The paper uses a Pressure-Life (P-N) curve to describe the basic capability of hydraulic hose similar to the Stress-Life (S-N) curve used for metal components. The standard cumulative damage equation used for metal components is also used to predict fatigue life. The paper illustrates how to perform tests to establish P-N curves. It discusses how to cycle count variable amplitude pressure histories for use in the damage equation to predict fatigue life. A comparison of variable amplitude and constant amplitude results is used to illustrate accuracy of the prediction method.