本科毕业设计-曲轴连杆机构的的有限元模型说明书.doc

摘 要 随着车辆保有量的增长，车辆噪声已成为城市噪声的最主要来源。发动机的振动噪声，是车辆噪声的最大来源，所以积极开展针对发动机噪声的分析和控制方面的研究工作，对于改进发动机结构，提高舒适性具有重要的现实意义。 发动机工作时 ，由于冲击、摩擦、旋转不均匀和不平衡力作用等原因，激起零部件的机械振动而产生噪声。 特别是当激振力频率与零部件的固有频率相一致时，会引起激烈的共振和噪声。本文以常用的四缸发动机（BJ-130轻型载重汽车）为例，应用UG6.0软件建立发动机曲轴连杆机构各组成零件的几何模型，并装配形成机构的三维实体模型。然后转换成.stp文件导入ANSY WORKBENCH 13.0进行模型简化并进行模态分析，得到机构的振型及固有频率，输出结果之后将曲轴连杆机构的有限元模型写成.dat格式，通过导入到ANSYS13.0转化成.cdb格式。最后，将模型文件导入Virtual Lab进行振动噪声分析并得出结论。 关键词：曲轴连杆机构，模态分析，有限元模型，振动噪声分析 Abstract Along with the growth of the vehicle possession,the noise of vehicles has become the main source of urban noise.The vibration noise of the engine is the biggest contributor to the vehicle noise.So carrying out actively the analysis and control work of engine has the important and practical significance for improving the comfort of engine。 As the engine works,the engine may generate the mechanical vibration and parts noise because of the shock,friction,roting unevenness,unbalanced force and other reasons.Especially when the frequency of exciting force and the natural frequency of the parts is consistent,it can cause the fierce resonance and noise.In this paper,as the commonly used four-cylinder engine(BJ-130 light truck)for example,establishing the geometric model of the constituent parts of the crankshaft and connecting rod mechanism based on the application of UG 6.0 software and assemblying into a three-dimensional solid structure.Then importing it into the ANSYS WORKBENCH13.0 after converting the .stp file to simplify the model and complete modal analysis ,the vibration mode and natural frequency of the mechanism can be achieved.And the finite element model of thel crankshaft and connecting rod mechanism can be written to become format of.dat.Through introducing towards ANSYS WORKBENCH 13.0 to translate into .cdb format.Finally,to import the model files into Virtual.Lab so as to conduct vibration and noise analysis. Key Words: the crankshaft and connecting rod mechanism，modal analysis，finite element m