山地果园轮式运输机车架结构分析与优化

山地果园运输机是农业运输机械化的重要组成部分,车架作为汽车质量的支撑部件,决定了运输机结构合理及行驶安全。该文研究的山地果园轻简化轮式运输机车架属于发动机前置后驱形式,利用Pro/E软件建立三维模型,并导入ANSYS软件进行有限元模态分析。在通过静态电测试验确定有限元分析的应力值和试验真实应力值在合理范围内后,对车架模型关键部位进行载荷、约束等处理并进行有限元静态弯曲和应变力分析、车架有限元模态分析,及有限元前8阶模态振动变形分析。分析结果表明车架具备良好的强度和刚度特性,存在一定的优化空间。优化过程在满足车架强度和刚度要求的前提下,通过改变横梁布置结构并降低车架构件板厚的方式实现轻简化目的。优化结果为上车架体积减少20%左右,整个车架体积减少12.37%左右,使车架质量降低了12.4%,最大应力和最大变形远远小于屈服极限值,较好的达到了车架轻量化的优化目的。

Analysis and optimization of frame structure for wheeled transporter in hill orchard

In China, the transportation condition of citrus plantation was so poor that it is needed to develop an energy-saving, simple and secure, low speed but high torque hill orchard wheeled transporter for farm goods transport. As the supporting part of vehicle load, the stiffness, strength and toughness of transporter frame determined rational structure and driving safety. However, when performing analysis of vehicle frame at home and abroad, they still used dynamic factor to represent the dynamic load of frame and used static strength as the design criteria of the frame, but the actual load of the frame is usually to be a dynamic load, which leaded to the fact that dynamic factor and static strength could not accurately describe the real-time stress state. Since the traditional frame design methods are very difficult for considering the complex stress and deformation situation of transport, finite element method would be the right way to solve this problem by using structural modal analysis to get the dynamic characteristics of the frame structure. The simplified mountain orchard wheeled transport was studied using front-engine rear-drive form, and this paper established a three-dimensional model of the transport frame through the Pro/E software and then imported the 3D model into ANSYS software for finite element modal analysis. During the study, we came to use static electricity test and model analysis to explore the optimum structure. According to static electricity test, its test result showed that the relative error between the stress of finite element analysis value and the test actual value was in a reasonable range. After loading and constraint handling to the key parts of the model, the paper conducted finite element static test analysis, transport frame bending and strain analysis, and the first eight order modal vibration deformation for finite element analysis of the frame. The analysis results show that the transport frame has a good strength and stiffness properties, which proves that it exists a certain optimization space. The results of tests and analysis above both lead to the solved method that we could reach the purpose of thickness by changing the structure of the car frame. In the premise of meeting the requirements for strength and stiffness of the frame, the paper puts forward a solution to achieve the purpose of simplification by changing the beam arrangement and reduce the thickness of the frame member. Based on the program of working condition and torsion condition of full load bending, the result shows that the second project performs better and has a good character. After the optimization, it reduces the size of the upper portion of the frame by about 20%, and the volume of whole transport frame by about 12.37%, so that the frame quality is reduced by 12.4% as well as the maximum stress and maximum strain is far less than the yield limit. Therefore the paper draws a conclusion that the optimization has preferably reached the frame lightweight purposes.