基于疲劳累积损伤的板弹簧疲劳寿命预测与实验研究

Prediction and experimental study on fatigue life of flexure spring based on fatigue cumulative damage theory

在斯特林发动机板弹簧理论研究模型基础上,建立疲劳强度有限元模型,以位移方式加载模拟其工作过程,研究板弹簧在实际工况下的变形与应力状况,并采用Gerber模型计算板弹簧疲劳强度。然后,基于板弹簧工作疲劳载荷谱,利用疲劳累积损伤理论,建立弹簧疲劳寿命预测模型。研究表明板弹簧疲劳失效发生在涡旋臂根部,选取合适的型线结构以及弹簧材料,可以使得弹簧满足疲劳强度和工作寿命要求。最后,搭建板弹簧疲劳寿命实验台对疲劳寿命仿真预测模型结果进行验证。结果表明,建立的板弹簧疲劳寿命预测模型准确,研究方法有效,结果可信。

Mechanics model of involute flexure spring was established. The finite element method was adopted to establish the fatigue strength dynamic simulation model. The displacement and stress of the spring under the actual work condition was studied through the displacement loading method. Fatigue strength of flexure spring is calculated using Gerber model. Based on work fatigue load spectrum of flexure spring, fa- tigue life prediction model of flexure spring is established by the fatigue cumulative damage theory. Studies show that flexure spring fatigue failure occurrs in the root of spiral arms. The fatigue strength and working life requirements can be satisfied by selecting suitable line structure and spring material. Finally, the fatigue life experiment platform of flexure spring is used to validate the simulation model and the results are consist- ent. The results show that the prediction model of fatigue life of flexure spring is accurate, research method is effective and results are believable.