| In general, when we using ANSYS Classic interface for static and dynamic analysis, the workload is heavy, and the analysis process is vague. The paper takes a dump truck as research object, and try using the finite element analysis software ANSYS Workbench for dynamic analysis of sub-frame based on the finite element dynamics theory, the analysis process is clear and simple, and which can realize data sharing between different modules.According to drawings provided by the manufacturer, the geometry model of dump truck sub-frame is establish based on finite element software ANSYS Workbench, the finite element model of sub-frame is carried out after meshing, and the modal natural frequencies and shapes are got by freedom modal analysis of sub-frame; Then adding spring suspension system and constraints on the sub-frame based on the actual situation, the amplitude-frequency response curves on the after flip-axis are obtained though the harmonic response analysis of the excitation of engine and wheel unbalance; Finally, the displacement power spectrum analysis of road excitation is carried out, and the stress-frequency, displacement-frequency and response power spectral density of the after flip-axis are got when dump truck running with different speed in the E-class road.By the analysis result of dump truck sub-frame free modal, the sub-frame design is reasonable, without local shortage. According to the actual usage, and considering the engine incentive, wheel imbalance incentive and the road excitation are carried on the dynamic analysis of the sub-frame, the results of this study showed that:①The harmonic response analysis of wheel unbalance excitation contains bending working condition and twisting working condition, under two conditions the largest peak frequencies are6Hz, while avoiding the frame inherent frequency, but the maximum displacement of sub-frame after turn axis of Y direction are39.859mm and47.655mm under the low frequency, the sub-frame with larger deformation.②In random response analysis, the dump truck with43km/h(12m/s) and57km/h(16m/s) driving in E road, according to the cloud chart of stress-frequency, displacement-frequency of sub-frame after turn axis, the maximal stress and displacement are261.58Mpa,84.284mm and402Mpa,194.750mm.The sub-frame is satisfied the stress condition under two kinds of speed, but the after turn axis has large deformation, the failure is consistent with most of user reactions, so in addition to the fatigue damage during loading and unloading, the wheels unbalanced and the road random excitations are main causes of sub-frame breakage.The innovation of this paper:the sub-frame is analyzed directed by Workbench, which has a strong practically analysis process, saving a lot of work time; Power spectrum instead of time-course on the sub-frame random response analysis, we get that road excitations result in sub-frame random fatigue, and led to sub-frame cracks or fracture. |
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