Abstract: To address the insufficient accuracy of traditional S-N curve-based methods in predicting the low-cycle pulse fatigue life of thin-walled electric water heater liners, a fatigue life prediction method based on the strain-life (ε-N) theory is proposed. Leveraging the HyperWorks platform, a pulse pressure life prediction model for the liner was constructed by combining OptiStruct static analysis under extreme conditions and the ε-N fatigue calculation module in HyperLife. The predicted fatigue life for the original liner model was 23,829 cycles, while physical testing yielded 18,926 cycles, resulting in an error of 25.9%. By optimizing the head curvature design, the plastic strain at critical areas was significantly reduced. The predicted life for the optimized model increased to 175,864 cycles, representing a 7.38-fold improvement over the original design. Physical testing of the optimized liner confirmed a life of 160,725 cycles, with the error reduced to 9.4%. The study demonstrates that this method effectively quantifies low-cycle fatigue damage in the liner, achieving prediction accuracy suitable for engineering applications. It drastically reduces the traditional reliance on physical testing, shortening the development cycle from weeks to 2 days~3 days and cutting R&D costs by approximately 70%, thus providing an efficient and high-precision solution for the reliability design and life prediction of pressurized components in household appliances.

Key words: HyperWorks, Electric water heater liner, Pulse pressure, Life prediction