Study On Design Technologies Of Motorcycle Frame Structure

It will be a great advantage if the dynamic characteristics and dynamic response of motorcycle frame can be got during the development process because some relevant measures can be adopted at early stage and costs will be reduced. The design methods based on Finite Element Method (FEM) and Optimization Design theory have been widely applied because of the quick development of the computer technology and numerical analysis method. Based on the study of main factors influencing motorcycle frame vibration during the development process, using the Modal Analysis method, Harmonic Analysis method, Global Sensitivity Analysis method and Optimization Design method, the dynamic characteristics and the dynamic response of a new 250 motorcycle have been studied. An optimization of frame structure was carried on and it was proved effective. Procedures of motorcycle frame design and analysis had been summarized with a conclusion of optimization procedures which can be an import reference to motorcycle frame design. The main research contents and consequent conclusions are as follow:①The main factors working on the frame vibration are researched. The amplitude and frequencies of the second reciprocate inertia force are obtained by the analysis of engine dynamics and its balance of vibration. The least frequency of the frame is got through the analysis of the forced vibration caused by road excitation. Analysis result of frame structure, suspension and tire system shows that the motorcycle vibration performance can meet the need only if the whole system had been matched.②The analysis process had been realized automatic and intelligent by building the parametric frame and parametric whole model using the ANSYS/APDL. Some key problems in parametric modeling such as the definitions of structures with different properties, the recognizing the points number, the variety of the width of shells, the movement of the front suspension, had been solved by using the ANSYS inner functions.③The analysis model was proved correct by contrast the analysis result with the test. The parameters of the structure had been optimized using the Global Sensitivity Analysis method and Optimization Design with the result that the dynamic characteristics of frame were improved.④Based on the restriction modal analysis of the optimal model, the method of getting the analysis amplitude and frequencies is researched. The dynamic response of the whole model had been got by using the harmonic analysis technology. A optimal frame structure was got by using the Sensitivity Analysis method and Optimal method with the assistant of manual modification.⑤A new method of the analysis technology for motorcycle frame and its analysis procedures has been concluded.