【作者】 吴国洋；

【导师】 陈小安；

【作者基本信息】 重庆大学 ， 机械制造及其自动化， 2004， 硕士

【摘要】 LX150摩托车曲轴箱包括左曲轴箱和右曲轴箱两部分,是摩托车的重要组成部分,其强度与稳定性对整个摩托车有着至关重要的影响。随着摩托车工业向高速、轻量化方向发展,其材料选择成为国内外学者所关注的研究课题。由于我国摩托车工业大多采用日本的技术,国内对曲轴箱的强度、稳定性方面的研究很少。目前我国的摩托车曲轴箱工作一定时间后容易出现开裂现象。采用新材料、改造其结构来提高曲轴箱的强度与稳定性更是实际中亟待解决的重要课题之一。本文基于国家科技攻关基金项目(批准号:2001BA311A05-4)的资助,围绕摩托车曲轴箱非线性动力学与静力学问题进行了相关研究。用有限元法建立了曲轴箱的静力学模型,在有限元应力与位移分析、有限元模态分析和有限元响应分析等方面取得了一定的研究成果。论文的主要内容包括:1.介绍了曲轴箱有限元建模的方法和有限元的基本理论、有限元分析软件的选择,确定了材料性质的方法,得出了外载荷与曲轴箱体轴承孔载荷的参数,指出了载荷边界条件、位移边界条件(约束条件)等边界条件处理的方法、建立了左右曲轴箱有限元的分析模型。 2. 用I-DEASMaster Series TM6.0集成化软件对曲轴箱进行了分析、求解,得到了其工作时的应力云图、位移云图、应力位移云图,对原有结构提出了三种改造方案。得出了采用增加箱体右侧凸缘壁厚、扩大凸台范围与增加加强筋相结合的方法能使箱体的应力与位移有较大降低的结论,并得到实验证实。验证了原有材料——铝合金在四种结构下对应的应力与位移工况。3. 建立曲轴箱结构系统的有限元动力学分析模型,用Lanczos法计算了左右曲轴箱的前10阶固有频率和振型特征,得出了曲轴箱在工作状态下不会出现共振现象的结论。 4. 建立了左曲轴箱、右曲轴箱及其三种改造结构的动态响应有限元动力学分析模型,利用I-Deas软件的振型叠加法分别对各种结构进行了动态响应分析,得到了箱体表面的法向振动加速度-时间历程以及法向速度---时间历程。更多还原

【Abstract】 The LX150 Motorcycle Crankcase Box(MCB) is component of the left Crankcase Box and right Crankcase Box, which are the important parts of the Motorcycle. The intensity and stability of crankcase box crucially effect on the function of the whole Motorcycle. With the development of Motorcycle industry towards high speed and lightweight, the selection of material has become hot topic of scholars all over the world. Since most motorcycle technologies of our country are introduced from Japan, the researches on the intensity and stability of MCB in our country are few. At present, the crack is found after the MCB runs a certain time in our country. Then, to enhance the intensity and stability of Crankcase Box through adopting new material and optimizing its structure are the important topics which need solved.Sponsored by National science-technology key program (No.2001BA311A05-4), this paper researches on nonlinear dynamic and static problems of MCB, builds up static model with finite element method, and achieves some fruits. The main contents of the thesis are as followed:1. The paper introduced the modeling methodology, basic theory of finite element, the selection of analyzing software, the method of decided material property, the method of obtained parameters of exterior load and the load of Crankcase Box’s bearing hole, indicated how to deal with limited conditions of load and displacement, and built up finite element analyzing model of left and right Crankcase Box.2. Analysis and question solution were done to Crankcase Box with I-DEAS Master Series TM6.0 integrated software. Stress graph、distortion graph and stress distortion graph had been gained. Three improved projects on original structure were put forward. In order to reduce the stress and distortion of Crankcase Box, the method of adding flange thickness and enlarging protrusion width together with augmenting tendon was presented. An example validated that the method was available. Author validated corresponding stress and displacement of original material aluminium alloy in working condition.3.Finite element dynamics analyzing model of Crankcase Box’s system structure was built up, and computed anterior ten ranks intrinsic frequency and vibrant graph character of left and right Crankcase Box with Lanczos method. The conclusion that in working condition syntonic phenomenon can’t occur in the Crankcase Box was came to. <WP=6>4.Finite element dynamics analyzing model of left and right Crankcase Box and its three improved structures’ dynamic response were established, and dynamic responses of all kinds of structures were computed with the method of vibrant graph congruence using I-Deas software. The vertical librating acceleration relative time and vertical speed relative time graphs of Crankcase Box’s surface were obtained更多还原