Research on reliability assessment method of harbinger solenoid valves based on multi-physics field coupled degradation

In response to the insufficient research on the multi-physics coupling degradation mechanisms of solenoid valves, a dual-factor coupled reliability model integrating spring stiffness degradation and seal leakage degradation is proposed. An EDECM model (Nonlinear Exponential Decay with Environmental Compensation) is established to characterize the time-varying spring stiffness, and a TSFCDM model (Triple-Stage Fractal Contact Degradation) is constructed based on fractal contact theory to describe the seal leakage degradation. Additionally, Wiener processes are introduced to depict the stochastic fluctuations of parameters. Monte Carlo simulations reveal that the reliability of the solenoid valve first drops to the 0.999 threshold within 296,000 usage cycles, with significant dispersion in the failure threshold distribution due to parameter uncertainties. Compared with traditional single-factor models, this coupled model effectively reduces prediction deviations by quantifying the bidirectional degradation mechanisms, meeting the precision requirements for the reliability threshold (>0.999) of aeronautical equipment.