Lightweight Study Of Motorcycle Based On Structural Optimization Method

As a kind of representative vehicle, motorcycles are always popular among peoplefor their economical and convenient properties. After lightweight design, theperformance of a motorcycle’s vehicle control, acceleration and stability will beimproved，while noise and vibration will be decreased, which is vital for theperformance improvement of motorcycles. So the research of lightweight onmotorcycles is of great significance. Generally speaking, lightweight research onmotorcycles is to reduce the dead weight of motorcycles on the basis of the currentscience, technologies, modern design concepts or new materials on purpose ofenergy-saving, environmental protection and improving the performance of objective,meanwhile, the requirements of the components should be met.In this paper, it reports the historical background of structural optimizationdesigning and the application of optimization techniques in lightweight research. Onbasis of the summary of the basic theory and methods of structural optimizationtechniques, the structure optimization techniques are applied to the design of frame andseat-cushion bottom of a motorcycle, resulting in the decrease of the dead weight of themotorcycle.Taking a certain motorcycle frame for a example, firstly, modal analysis is appliedto the frame to evaluate its dynamic performance with ANSYS Workbench，and thenaccording to the results calculated above, the improvement program of the framestructure was made. Secondly, the size optimization design on main component of themotorcycle frame was taken. Finally, based on the results of the size optimizationdesign, the stiffness and strength of new frame was checked.Taking a certain seat-cushion bottom for an example, based on the softwareplatform--Altair Optistruct, the technique, combined topology optimization with shapeoptimization, was used to design the seat-cushion bottom, aiming for the minimum totalvolume of it. And then the excess part of the seat-cushion bottom was removed,achieving the purpose of lightweight.With the finite element method gradually being introduced into the motorcycles’design and research, not only can the strength and stiffness of vehicle structure beanalyzed in static or moving state, but it can achieve the optimum size or distribution ofmaterials of components, saving the materials and reducing the costs, what is more, it can reduce the stress concentration of the target structure to a certain extent, which isimportant for the design of the general structure of motorcycles.