Probability Evaluation Method for Thermal Fatigue Life of Surface Mount Components Based on Physis of Failure Simulation

The nuclear instrument control systems contains tens of thousands of surface mount components. The evaluation of thermal fatigue life in the design stage is helpful to ensure the continuous and stable operation of the operation stage. When analyzing the thermal fatigue life of surface mount components, there are many uncertain factors, including random and interval uncertain variables. The thermal fatigue life without considering the fusion of multiple uncertainties may lead to the unreliability of the evaluation results. In this paper, a probabilistic evaluation method of thermal fatigue life based on physis of failure simulation is proposed. The interval variables are transformed into random variables to complete the characteristic parameter sampling based on the probability sampling method. Then, the uncertainty propagation is realized by random physis of failure simulation, and the thermal fatigue life is probabilistically quantified. A patch resistance case is used to verify the method proposed in this paper. The results show that the method can effectively fuse the random and interval uncertainty variables and obtain the thermal fatigue life probability results of the device.