【作者】 王晖云；

【导师】 朱思洪；

【作者基本信息】 南京农业大学 ， 机械设计及理论， 2007， 硕士

【摘要】 汽车车架是整个汽车的安装基体，汽车绝大多数部件和总成都是通过车架来固定其位置的，并且车架承受着车内外的各种载荷。车架结构不合理会带来车架的早期断裂问题，给安全带来隐患。深入研究车架的动态特性是车架结构设计、改进和优化的基础，也是保证整车性能的关键之一。因此，车架的研究具有极其重要的意义。本文以YT5815P型车架作为研究对象，首先按照一定的模型简化原则，应用Pro／E软件建立车架的三维实体模型。然后以有限元技术为基础，利用ANSYS软件建立汽车车架有限元模型。为了获得可靠的计算结果，单元类型采用板壳单元SHELL63，纵、横梁以及连接板之间的铆接关系通过梁单元BEAM4描述。在有限元模型的基础上，利用ANSYS软件强大的功能，以了解车架的振动特性以及为改善结构提供理论指导为目标，对车架进行静力分析以及动力学分析。通过静力分析，获得了车架在不同工况下(弯曲、扭转)应力及变形的分布情况。车架的动力学分析包括：模态分析，谐响应分析以及瞬态动力学分析。采用试验与计算机仿真相结合的方法对车架进行模态分析，获得了车架自由状态下的固有频率，并对其振动特性进行分析。同时，车架有限元模型的可靠性通过试验得到了验证。为了进一步考察系统的动态稳定性，对车架进行了谐响应分析以及瞬态动力学。最后，综合分析结果，对车架的改进设计提出了建议。通过本文的研究，掌握了车架的动态特性，为车架今后的进一步改进、优化设计以及抗疲劳设计提供了理论基础；另一方面为企业储备了车架数值模型和相关技术数据。同时，本文运用有限元技术，进行了有益的尝试，具有较强的学术和实用意义。更多还原

【Abstract】 As the base of vehicle, the frame, on which most of the parts and components are assembled, bears all kinds of loads from the vehicle. Obviously unreasonable structure of the frame influences driving safety and steering stability. Research on the loading characteristic of vehicle is not only the groundwork of the design and optimization of a frame, but also of great importance for the whole performance of vehicle. So, it will be realistically significant to study the dynamic character of the frame.Firstly, according to simplified rulers of the model, 3D model of the frame was established by using Pro/E. Based on finite element method and vibration theory, software ANSYS was applied to build the FEM model of YT5815P frame. In order to ensure reliability of calculation results, shell63 was selected as basic element and beam4 was used to simulate rivet joints in ANSYS. Based on the FEM model, static and dynamic responses of the frame were simulated and analyzed. This paper could obtain not only the dynamic characteristics of the frame, but also provide dates with optimization and fatigue design through analysis. The stress distribution and deform distribution of the frame under different work conditions were gained after static analysis. Dynamic analysis includes modal analysis, harmonic analysis and transient analysis. Natural frequencies of the frame were obtained through modal analysis and the results were analyzed. Experimental modal results confirmed that the FEM model was reliable. After studying static and modal characteristics, dynamic stability of system was researched according to the results of harmonic analysis and transient analysis. Finally, some suggestions were given combining static and dynamic analysis results.The research of the paper not only obtained the vibration characteristic of the frame, provided basic theory for frame design, but also reserved a valuable numerical model and relevant technical data for the factory. Meanwhile, FEM was used successfully. Such an attempt was valuable both in academic research and in practical technology.更多还原