The fatigue life for the rear suspension lower arm of the passenger car is investigated. The road load signals collected by the sextant force measuring instrument are processed. And the frequency histogram of it is plotted and its distribution characteristics are analyzed. The load signal is extrapolated to a cumulative frequency of 10 6 using the parametric method, and the onedimensional load spectrum of the lower arm is compiled. Based on the nonlinear fatigue cumulative damage theory, Corten-Dolan model is modified by introducing the kth power of the stress ratio between two adjacent levels. The improved fatigue life prediction model is established and the validity of the model was determined by experimental data. And the improved Corten-Dolan and the linear cumulative damage model are used to predict the life of the lower arm under one-dimensional load spectrum respectively.

Automotive drive shaft is an indispensable key component of the transmission system, and the use of composite drive shafts has shown great promise. The epoxy matrix of the shaft is susceptible to the effects of temperature in comparison to carbon fiber. To investigate the influence of the environmental temperature on the fatigue life of a carbon fiber‐reinforced plastic drive shaft, a temperature‐based property curve and performance fraction model for the shaft are established. The temperature coefficient is calculated and introduced by combining the collected temperature data with the property fraction function. A generalized S‐N surface of the composite drive shaft is proposed based on experimental data. The fatigue life under collected and processed random loads of the carbon fiber‐reinforced plastic drive shaft is predicted by modified Miner's law. The effect of mean, amplitude of load and ambient temperature on fatigue life are taken into account.