Research On Anti-fatigue And Lightweight Problem Of Frame Of Mining Dump Truck Based On Stiffness Chain Method

In this paper,the object of this study is a 220 t large-tonnage mining truck,relying on the National 863 Program "the large-tonnage dump truck development".The frame is the most important bearing components of the mine dump truck.In order to fully guarantee the stiffness and strength of the frame,the frame design of this study is conservative.However,in the case of a certain weight redundancy in the frame design,the fatigue cracking still appears in the long term service of the frame,which shows that the original frame has a larger optimization space for the fatigue life and the weight.Therefore,it is necessary to optimize the fatigue life and lighten the weight of the frame.In the current anti-fatigue and lightweight design problem,the structural stiffness is often considered as a whole target,that is,only the overall stiffness is need to be satisfied,and the stiffness distribution between the modules of the structure is seldom studied.It is found that the rational distribution of structural stiffness is an effective way to improve the fatigue life and reduce the weight redundancy.On the one hand,it will make some parts more weak and easily lead to fatigue damage under the cyclic loading if the structu ral stiffness is not reasonable.On the other hand,it may produce some parts of the stiffness excess,resulting in structural redundancy and material waste.Therefore,a stiffness chain design method is proposed in this paper,and the anti-fatigue and lightweight design of the mining dump truck frame is carried out based on the experimental and numerical simulation technology.The main contents are as follows:1.The fatigue life prediction of mining dump truck frame is completed.The rigid-flexible coupling dynamic simulation model of the mining dump truck is built,and the load spectrum of the frame is built based on this model.The finite element analysis model of the frame is established,and the accuracy of the model is verified through stress test.Through material fatigue life test,the material S-N curve is obtained,and the fatigue life prediction of the frame is carried out combined with the load spectrum of the frame.2.A stiffness chain design method is proposed.First,a stiffness performance evaluation system is proposed.The evaluation system quantifies the stiffness contribution of each module to the overall stiffness of the structure.Then,stiffness characteristic matching design is applied in the frame.The stiffness matching function is firstly set up.Then the stiffness performance target is decomposed into each module and thus the stiffness redistribution of each module is realize d.Stiffness performance evaluation system and stiffness characteristic matching design constitute the stiffness chain design method together.3.The anti-fatigue and lightweight design of the frame is carried out.The stiffness chain design method is used to guide the selection of design variables and provide constraints,and then the multi-objective optimization model of the frame is established.Finally the Pareto optimal solution set is obtained.The stress distribution and stiffness performance of the frame are compared before and after the optimization,and the rationality of the optimization method is verified based on the comparison result.4.An optimization platform for the anti-fatigue and lightweight design of the frame is developed.Based on the secondary development technology of VB for ANSYS,the platform integrates the function modules of stress analysis,stiffness analysis,stiffness contribution evaluation,parameterized analysis and structure optimization.The interface of the platform is designed friendly and easy to operate.It provides a convenient and efficient optimization tool for the anti-fatigue and lightweight optimization of the frame.