对称随机循环应力作用时零件的疲劳可靠度和寿命的预测方法

PREDICTION OF FATIGUE RELIABILITY AND LIFE OF PARTS UNDER SYMMETRIC RANDOM CYCLIC STRESS

以Ｍｉｎｅｒ理论为基础，考虑到影响疲劳损伤的主要物理量实际上为随机变量，提出单个循环的疲劳损伤量δ、零件的疲劳损伤强度Ｋ、零件的总疲劳损伤量Ｄ的计算式。从这３个随机变量出发，建立了一种疲劳累积损伤的概率模型。在对称随机循环应力作用时，可用该模型计算零件的可靠度和疲劳寿命。

Three new random variables are defined: δ as a fatigue damage quantity in a single cycle under cyclic stress, K as a fatigue damage strength of the part, D as an overall fatigue damage quantity of the part in the working life under the load spectrum.On the basis of three random variables a new probabilistic fatigue model is established,which can predict the fatigue reliability and life of the part under symmetric random cyclic stress.