Creep-shock fatigue reliability assessment of electronic component structures based on Bayesian estimation

To address the reliability issues of electronic components in reusable spacecraft under coupled high-temperature creep and pyrotechnic shock environments, this study takes ball grid array (BGA) solder joints as an example and proposes a creep-shock fatigue damage assessment method extending from deterministic to probabilistic approaches. First, a high-temperature creep-shock coupled test system is established to obtain life data of BGA solder joints under various combinations of creep dwell time and shock loads. Finite element analysis is conducted by combining the evolving power spectral density shock damage model and the Wen–Tu creep damage model to quantitatively characterize the creep damage and shock damage components under different operating conditions. On this basis, a creep-shock fatigue interaction diagram is constructed, and a nonlinear failure envelope applicable to BGA solder joints is established. Through the unified fitting of failure data from multiple conditions, consistent life prediction for different conditions is achieved, balancing safety and economy in engineering applications. Furthermore, to address the issues of limited experimental sample size and life dispersion, a method combining Bootstrap and Bayesian estimation is introduced to identify the Weibull life distribution parameters. Based on Latin hypercube sampling, random damage sampling simulations are performed to construct a probabilistic damage assessment chart containing probability equipotential lines of different confidence levels, which explicitly defines the safe design region and recommended envelopes under target reliability constraints. The research results provide a systematic method and engineering basis for the life design and reliability assessment of spacecraft electronic components under complex thermo-mechanical environments.