An accelerated shock fatigue life model for complex shock loads with load dispersion

This paper presents an accelerated shock fatigue life model based on load dispersion, which utilizes the experimental life data under high-magnitude loads to assess whether the structure meets the fatigue life design requirements under its original load conditions, thereby improving the experimental efficiency. Firstly, a shock fatigue life database is established by combining experiments with finite element analysis. Then, the shock load dispersion effect is quantified by data fitting, and the relationship between the shock response spectrum parameters and the Weibull parameters is obtained. Finally, a new accelerated shock fatigue life model is established by introducing a relative dispersion factor based on the inverse power law model. Taking BGA solder joints as an example, the shock fatigue damage equivalent boundary of BGA solder joints is calculated. The results show that the error between the predicted boundary and the actual boundary is in the range of −5 %–7 %, verifying the effectiveness of the model.