| Fatigue life of the structure is an important parameter to evaluate the quality of the vehicle. The traditional methods to predict the body fatigue life are generally carried out by the experiment of the vehicle prototype in the laboratory and the road test. But all of these methods have the disadvantages of long time, high cost, and it is difficult to calculate the structural life during the design period. In this paper, the simulation based on FEM is applied to analyze the fatigue life of a minibus body in a virtual environment. We use the softwares such as Hypermesh, MSC.Nastran, ADAMS/Car and MSC.Fatigue to realize the simulation. The research can provide technical supports for the design and improvement of the body structure while we don't rely on the prototype of a minibus.Firstly, the finite element model of body-in-white is established by advanced modeling technology, and dynamic characteristics of the body structure are investigated by modal analysis. Secondly, the model of fully loaded vehicle body is established. The working conditions are divided into different kinds according to the complicated road condition and the characteristics of loads. The static strength analysis is accomplished by inertia relief under different working conditions. The structural strength of the main parts of the body is also evaluated. Finally, the multi-body dynamics model of the minibus is established, and the load spectrum of fully loaded body under the B-level pavement is obtained. Fatigue life of the body structure is predicted with a nominal stress method, the interaction among unit load stress function, load spectrum and S-N curve are considered. The weak parts connected to chassis are analyzed within the hazardous locations.
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