Abstract: Aiming at the fatigue failure of SWH springs, the special SWH springs used by UAE companies were introduced as the research object. Firstly, the stress-strain history of the SWH springs was analyzed by finite element simulation, and the stress-strain distribution of the key region was accurately calculated by the sub-model technology. The correctness of the finite element model was verified through static response experiments. The fatigue properties of steel wire material were derived from the tensile test and the Manson model. Finally, the fatigue life of the SWH springs was predicted by combining the stress-strain history and the fatigue life prediction criteria, and the experimental verification was performed. The results show that：when SWH springs are compressed, the maximum stress is located at the outer steel wire of the end position and the outer steel wire is mainly subjected to bending stress, which is consistent with the situation of the fractured outer-layer steel wire at the end of the springs. The errors between the response simulation and the measured value do not exceed 5%; The fatigue life predicted by the SWT criterion is in good agreement with the experimental fatigue life, and the predicted fracture positions are consistent with the actual fracture positions.

Key words: stranded-wire helical(SWH) spring, finite element method, sub-model technology, static response, fatigue life prediction

摘要： 针对多股螺旋弹簧（多股簧）的疲劳失效问题，以阿联酋某企业使用的特种多股簧为研究对象，通过有限元仿真分析多股簧的应力应变历程并利用子模型技术进行了应力应变的精确计算，通过静态响应试验验证了有限元模型的正确性；进行了钢丝材料试验，结合Manson模型推导出多股簧材料的疲劳性能参数；结合多股簧的应变和疲劳寿命预测模型预测了多股簧的疲劳寿命，并进行试验验证。研究结果表明：多股簧承载时，弹簧端部承受的应力较大，最大应力点位于外层钢丝且外层钢丝主要承受弯曲应力，与弹簧端部位置处外层钢丝疲劳断裂现象吻合； 静态响应仿真与实测值误差不超过5%；由SWT准则预测得到的疲劳寿命与试验疲劳寿命较为吻合，且预测疲劳断裂区与实际断裂区一致。

关键词: 多股螺旋弹簧, 有限元方法, 子模型技术, 静态响应, 疲劳寿命预测