| Special engineering dump truck mainly runs in mine, construction site and other places, travells in poor road condition and often under severe overload condition. Frame is the important load-bearing structure of special engineering dump truck, cab, hydraulic lifting system, carriage, powertrain and axle and other assemblies or components are mounted on the frame rigidly or flexibly. Therefore, the performance of frame has a direct influence on vehicle performance. In the frame structure design, if we can accurately predict the fatigue life of the frame to prevent accidents caused by the frame fatigue damage, which will be a very important significance.With the development of computer science and CAE technology, CAE technology has been widely used in the vehicle structure design and development stage and subsequent analysis of the vehicle. In order to predict the fatigue life of the main and sub integrated frame structure of new R & D special engineering dump truck DT-002 under overload conditions(load 55 t, 70t), applying the finite element structural analysis, vehicle multi-body dynamics simulation, fatigue life and some other CAE technique analysis methods to analyze the frame structure. Taking into account the safety of the vehicle test in extreme condition, based on CAE technology and the modal stress recovery theoretical, this paper analyzes the frame fatigue life of the special engineering dump truck DT-002 under overload condition.Firstly, build the frame finite element model of dump truck DT-002 in the HyperMesh, set the material properties according to the frame material, and exert the boundary conditions combined with the actual working conditions of the vehicle, analyze the frame static characteristics of bending in static load, limit torsional state, initial lift state(0°) and maximum lift angle(45°) four kinds of conditions.Secondly, removing the boundary conditions of frame finite element model to conduct the DT-002 frame modal analysis in free state. Thus we can obtain the frame modal information in free state and simulate the free state to do frame modal test. Comparing the modal information obtained in experimental analysis with in finite element software, we find that the maximum error of natural frequency is 5% and each modes are consistent, which verify the credibility of the finite element model. Using component mode synthesis(CMS) to conduct modal analysis of frame finite element model, obtain the frame MNF modal neutral file and modal stress OP2 file.Then build the DT-002 dump truck rigid flexible coupling model based on the flexible frame in ADAMS software. In order to validate the vehicle dynamics model, we conduct the DT-002 dump truck road test, and obtain the frame and axle vibration signal when the vehicle runs on the test road of company and the road of construction site. Then conduct the vehicle dynamics analysis to verify the credibility of the dynamics model. According to the actual operating state of special engineering dump truck, controlling the vehicle speed in the 15-20km/h and selecting the class D road spectrum to conduct complete vehicle virtual road test, obtain the modal displacement-time history of flexible frame under extreme heavy load conditions, as the fatigue load of frame fatigue life analysis.Finally, predict the frame fatigue life of special engineering dump truck under heavy load based on modal stress recovery theory. Make modal stress file of CMS modal analysis and modal displacement history of vehicle virtual road test as the frame fatigue load, and combine the frame fatigue characteristic curve, to predict the frame fatigue life and hazardous area, ultimately we obtain the fatigue life contours. The results show that the method described in the paper can effectively analyze the frame fatigue life, which help to guide the frame structure optimization to enhance the market competitiveness of the dump truck. |
PDF Full Text Request