金属薄膜弹簧疲劳寿命预测

轻触式按键(1ight touch switch)在消费类电子产品和工业自动化中得到广泛的应用，其关键零件是金属薄膜弹簧(metal diaphragm)，疲劳破坏是其主要失效形式，预测其疲劳寿命是产品设计的重要内容之一。文中首先阐述金属薄膜弹簧工作应力仿真的模型和结果；其次给出进行疲劳试验数据处理的数理统计方法，利用概率纸和回归分析确定材料的统计分布规律，通过平移材料的S—N曲线得到相应的设计用S—N曲线；最后，通过在疲劳极限图上映射工作点应力状态，预测金属薄膜弹簧上各处的疲劳寿命，并和试验结果进行比较，二者较为符合。

FATIGUE LIFE PREDICTION OF METAL DIAPHRAGMS

Light touch switches are widely used in electronic appliances and industry automation. Metal diaphragm is the key part of light touch switch. Fatigue damage causes the metal diaphragm failure so life prediction of metal diaphragm plays a great role in product design. In this paper, first the principles and results of working stresses simulation are presented. Then probability paper and regression are applied and the distribution is identified. Based on test data and literal surveys, the simplified design criteria are put forward and design S-N curves are obtained by moving test S-N curves to the low cycles. By mapping stresses to fatigue limit graph, the life of any position on the diaphragm can be easily predicted. The test results are also presented and fit rather well.