Small-size ultra-thin leaf spring as the key elastic sensitive member is widely used in the precision electro-mechanical products. However, owing to the unavoidable elastic hysteresis effect of leaf spring, it always suffers from a significant graceful degradation of designed deflection and subsequently fatigue fracture under the condition of cyclic loading. In order to weaken the elastic hysteresis effect, structural optimization according to sequential quadratic programming method for reducing stress concentration of leaf spring was first carried out by simulations, and then the identification of elastic hysteresis effect for optimal leaf spring was carried out by experiments. Compared with the original design, the maximum deflection deviation for single cycle is decreased from 0.026 mm to 0.002 mm. For the sake of predicting the fatigue life of optimal structure of leaf spring being on the service, a loading block with multistage variable stress amplitudes was experimentally recorded and fitted by normal probability density function, and then a statistical probability method by mathematical analysis was proposed. Compared with the original design, the predicted fatigue life of leaf spring is 736000 loading blocks, which is ten times than that before structural optimization. A structural optimization for reducing stress concentration can significantly weaken the elastic hysteresis effect and enhance the fatigue life, which is benefit for the elastic stability of leaf spring during engineering application.

小型超薄板簧作为关键的弹性敏感元件，已广泛用于精密机电产品中。然而，由于板簧不可避免的弹性滞后效应，在循环载荷条件下，板簧总是会遭受设计挠度的显着下降和随后的疲劳断裂。为了减弱弹性滞后效应，首先通过顺序二次规划方法对板簧进行了结构优化，以降低板簧的应力集中，然后通过实验确定了最佳板簧的弹性滞后效应。与原始设计相比，单周期最大挠度偏差从0.026 mm减小至0.002 mm。为了预测板簧最佳结构的使用寿命，在试验中记录了多级变应力幅值的加载块，并利用正态概率密度函数进行拟合，提出了一种通过数学分析的统计概率方法。与原始设计相比，板簧的预测疲劳寿命为736000个加载块，是结构优化之前的十倍。降低应力集中的结构优化可以显着减弱弹性滞后效应并延长疲劳寿命，这有利于工程应用过程中板簧的弹性稳定性。实验记录了多级变应力幅值的加载块，并用正态概率密度函数拟合，提出了数学分析的统计概率方法。与原始设计相比，板簧的预测疲劳寿命为736000个加载块，是结构优化之前的十倍。降低应力集中的结构优化可以显着减弱弹性滞后效应并延长疲劳寿命，这有利于工程应用过程中板簧的弹性稳定性。实验记录了多级变应力幅值的加载块，并用正态概率密度函数拟合，提出了数学分析的统计概率方法。与原始设计相比，板簧的预测疲劳寿命为736000个加载块，是结构优化之前的十倍。降低应力集中的结构优化可以显着减弱弹性滞后效应并延长疲劳寿命，这有利于工程应用过程中板簧的弹性稳定性。这是结构优化之前的十倍。降低应力集中的结构优化可以显着减弱弹性滞后效应并延长疲劳寿命，这有利于工程应用过程中板簧的弹性稳定性。这是结构优化之前的十倍。降低应力集中的结构优化可以显着减弱弹性滞后效应并延长疲劳寿命，这有利于工程应用过程中板簧的弹性稳定性。