Abstract

A method applicable to a design of a motorcycle exhaust system in its early design process that predicts fatigue strength was developed. In this prediction method, vibrating stress, thermal stresses, stress resulting from component assembling of the exhaust system and deterioration of strength of materials originated from fatigue by high temperature are simultaneously taken into account. For the prediction of vibrating stresses, flexible multibody dynamics was applied to get accuracy of vibration characteristics modeling for the entire motorcycle structure and for exciting forces delivered from the engine vibrations. Thermal conduction analysis and thermal deformation analysis based on finite element method (FEM) were applied for the prediction of thermal stresses caused in the exhaust system components. For prediction of the thermal stresses, temperature distributions on the surfaces of the exhaust system components are required. To estimate the temperature distributions, heat transfer analysis, which is composed of a one-dimensional (1D) engine cycle simulation and an air flow simulation for the air around the vehicle by 3D-CFD, was implemented. For the validation of the developed method, correlations between the results of simulations and actual measurements were analyzed for the vibrating stress, the temperature distribution, the thermal stress and the fatigue safety factor. High correlations were yielded between them proving the validity of the new method.In this paper, some of the application examples of newly developed method to an early stage of the development process are also presented. Through the examples, it is shown that the application of the new method effectively help designers implement feasible measures for potentially frail areas against fatigue. As a consequence, the new method enhances the efficiency of the development of the exhaust system.

References

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Author (organization or company)

• Hiroshi KURIBARA（Motorcycle R&D Center）
• Kenichiro NAKAMURA（Motorcycle R&D Center）
• Hiroshi HORIKAWA（Motorcycle R&D Center）
• Takashi TERAGUCHI（Motorcycle R&D Center）
• Takanori NAGATA（Motorcycle R&D Center）
• Daisuke KITAMURA（Motorcycle R&D Center）

Publication Information

Article of Honda R&D Technical Review Vol.29 No.1 (138 - 152)

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