Fatigue Life Analysis For Heavy Vehicle Cab Based On Modal Frequency Response

With the development of computer as well as CAE technology,it is possible to predict fatigue life of product during design stage.The reliability of structure has been long concerned by people.CAE software can be used to analyze the structural strength and fatigue reliability problems.This method can optimize the product development cycle,reduce product design and development costs.During traditional fatigue design analysis,the time domain signal has less rule unless it is long enough to has statistical significance.By frequency response analysis,the stress response transfer function of the structure near the natural frequency is obtained,which solves the problem of the signal length in the time domain and optimizes the operation rate.Therefore,fatigue 1ife prediction of the cab is analyzed on frequency domain in this paper.A cab is taken as the research object in this paper.First,the finite element model of the cab is established,the modal and static intensity analysis is carried out.Based on this,frequency response analysis is performed with the vertical unit acceleration excitation input,and the transfer functions between input and structural stress are obtained.After that,the cab-frame rigid-Flexible coupling model is built and then the acceleration power spectral density is obtained.Finally,according to transfer functions,acceleration power spectral density,the cab fatigue life can be predicted combined with Dirlik method.The results are in accordance with the bench test,and this method is valid to evaluate cab structure fatigue life at product design stage accurately and efficiently.