Life Estimation of Generalized Nonlinear Accelerated Degradation Process

The requirements for product service duration and reliability in aerospace and related fields continue to escalate, where performance degradation under prolonged operational conditions has emerged as the primary failure mode. Accelerated degradation testing has become a critical approach for validating long-term service reliability. Addressing the complex nonlinear time-varying characteristics observed in accelerated degradation processes, this study proposes a generalized nonlinear accelerated degradation model to characterize distinct time-varying patterns in both degradation mean and variance. Subsequently, the approximate distribution of the first-hitting time for the proposed model is derived. Finally, the validity of the proposed methodology is demonstrated through accelerated degradation testing conducted on a certain type of LED device.