Reliability modeling of a jet pipe electrohydraulic servo valve

The hydraulic system and its components can accumulate a significant amount of contaminant after running for a period of time. The accumulated contaminant in the component will degrade its performance and even cause catastrophic failure. Traditional models are distinctly deficient when applied to analyze the performance degradation. In this paper, an improved method is proposed to trace the performance degradation during a long time operation. By means of a novel failure injection performance degradation simulation framework (FIPDS) to inject failure mechanisms into the performance model, we develop a complete reliability model of a jet pipe electrohydraulic servo valve considering multiple failure modes and mechanisms based on failure modes, mechanisms, and effects analysis (FMMEA). The performance indexes rated flow and null bias are obtained from the model simulation to evaluate the performance degradation. Simulation results demonstrate the feasibility of the method in this research.