疲劳损伤的模糊性研究

针对疲劳极限以下小载荷造成的疲劳损伤问题，依据模型数学理论，引入“造成损伤”这一模糊子集，定义其隶属函数，导出了隶属函数与损伤的关系，建立了模糊累积损伤计算模型以及相应的疲劳寿命计算公式，并采用2个不同的载荷谱，对构件疲劳寿命进行了预估。通过与实测寿命比较，找出了对不同载荷谱选择不同隶属函数的规律，使两种载荷谱下疲劳寿命预估的误差由原来的62．58％、61．65％分别降低到4．03％和0．53％。结果表明，用该方法预测构件的疲劳寿命比传统方法更加准确。

Fuzziness study of fatigue damage

For the matter of fatigue damage caused by small load under the constant amplitude of fatigue limit,according to the fuzzy mathematical theory, the fuzzy subset of causing damage is introduced, its belonging function is defined, and the relation between its belonging function and the damage is deduced. A fuzzy accumulative damage model and its fatigue life calculating formula are established. The structure fatigue life is predicted by two different load spectrum respectively. Compared with the test results, the law of selecting belonging function for the different load spectrum is found, and the errors predicted fatigue life are reduced from 62. 58%,61. 65% to 4.03% ,0.53% for this two different load spectrum respectively. It proved that the predicted fatigue life by this method is more accurate than traditional way. 4 tabs, 7 refs.