| low-speed heavy-duty truck produced by a company in Guangxi, mainly transport in the short-distance in urban and rural areas, are widely uesd by the virtue of low prices,and cargo capacity. Since the low-speed heavy-duty truck is mainly used in the transport of rural and urban suburbs, and driving traffic are much more severely, to brought the user great security risk. So to solve the problem of fracture and deformation of the frame, to identify the cause and seek a reasonable solution is imminently. In this paper, we made a study of the dynamic characteristics of the truck frame,adopt modal stress method to studies fatigue life and on the basis of above for optimizing the structure of the frame,ultimately get the flexible body chassis improvements.Because of these problems exist frame member, studied several reasons which may lead to fracture of the frame, found the main cause of the frame, and to improve the frame based on the analysis, so that the frame can meet requirements. Firstly, use two-dimensional drawings of the frame, to create a solid model of flexible body frame.Before importing Hyper Works software, to make a reasonable simplification of the frame and use shell elements to construct CAE model of the frame for subsequent research and analysis.Secondly, compared with the finite element and experimental method to analysis the freedom modal and operational modal of the frame and to obtain the frame of dynamic parameters and modes, by comparing the results with the free mode also prove the rationality of the frame model.Third, using adams software to built vehicle model,and combined with excitation signal that acquired in experiment to do multi-body dynamics analysis. To obtain each modal shift of the frame, that is, dynamic load time histories, for the fatigue characteristics analysis of the frame provide a reference.Fourth, combined with the frame material 16 Mn selecting appropriate S-N curve,also combined with the previously obtained dynamic loads and in the mehtod of modal stress recovery to analysis the fatigue properties of the frame, got the life of the fram,based on the results for the frame modified to provide references.Finally, to optimize the frame based on the weak position of the results of the modal analysis and calculated fatigue, and to do fatigue life calculation for the improved frame,and Comparison with the previous optimization improvements, test effectiveness of the improvement.In this paper, through the analysis of the frame modal characteristics and the analysis of fatigue life which are based on modal stress recovery method. For enterprises established a numerical model and analyze data. At the same time, based on analysis of data, for enterprises to solve the problem of fatigue fracture, provides improved programs and got better results, for enterprises to solve the problem of fatigue fracture of the frame. |
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