为有效提高全寿命分析的准确性，采用有限元法预测排气系统的疲劳耐久性; 将 名义应力法与动态疲劳分析方法相结合，提出了一种基于动态响应的全寿命分析方法． 该 方法采用模态频率响应计算结构在不同频率激励下的应力响应，进而以应力响应为疲劳 载荷并结合材料的疲劳特性和 Miner 线性累积疲劳理论，计算得到结构的疲劳寿命． 以某 型轿车排气系统为研究对象，分析其在发动机扭矩激励和振动激励下的机械疲劳寿命，仿 真结果表明，该排气系统的耐久性满足要求．

To effectively improve the accuracy of total life analysis， the finite element method is used to predict the fatigue durability of exhaust systems in this paper． A method of the wholelifespan analysis based on dynamic responses is proposed by combining the nominal stress method with dynamic fatigue analysis． The method applies modal frequency response analysis to calculate the stress response to the structure under different frequency excitation． Ｒegarding the stress response as fatigue loads， the fatigue life of the structure is calculated on the basis of the fatigue characteristics of the material and the Miner linear cumulative fatigue theory． Taking a car exhaust system for the research object， its mechanical fatigue life under engine torque excitation and vibration excitation are analyzed． The simulation results show that the durability of the exhaust system meet the requirements．