250MN挤压机结构设计与优化毕业设计论文.doc

摘 要 金属挤压加工是利用金属塑性压力形成的一种加工方法。它的本质是利用施加外力的方法，使处于剂压容器中的坯料承受三向应力而产生塑性变形，并从特定的缝或者孔隙中挤出，从而获得一定尺寸及截面形状挤压制品的压力成形过程。本课题的研究来源于重庆大学承担的中国重型机械研究院科研项目“250MN挤压机结构设计与优化”，任务是250MN挤压机关键零部件的强度校核与优化。 挤压机中的关键零部件有前梁、后梁、动梁、主缸等，这些零部件的工作性能直接影响到挤压机的整体工作性能，因此要对其中一些关键零部件进行强度校核和优化。本课题通过提供原始图纸及参数，运用传统方法对挤压机前梁、后梁进行强度校核，然后用UG进行关键零部件的三维建模，并运用有限元分析工具ANSYS按照初步设计进行强度分析，得到挤压机主要零部件的应力情况。在初步设计的基础上，按照给定的安全系数，对结构进行优化。这主要通过增加梁高度来实现。最后可以得出结论：初始方案中前梁、后梁、动梁在结构上均存在有待提高的地方，部分零部件不符合强度要求。经过优化设计后，零件的主体结构均能达到强度要求，但在以后的设计中，应力集中区域还需要进一步优化。 关键词:挤压机，有限元，优化设计，ANSYS  ABSTRACT Metal extrusion is a processing method by using metal plastic pressure. An extrusion machine is a device which pushes or pulls the material in the extrusion containers through a shaped die to form a continuous length of product with a preset cross section. The material will be in state of hydrostatic pressure in the process. In this way, various profiles of products could be processed. This thesis is based on a research project undertaken by Chongqing University sponsored China National Heavy Machinery Research Institute with the title of “250 MN Extrusion Pres Design and its Optimization”. The tasks of this research are to verify strength of the key components and optimization. The key components in the extrusion press include front ridge, rear ridge, moving ridge, the hydraulic cylinder and so on. The performance of the designed components will directly affect the overall performance of the extrusion press, and therefore, it’s necessary to verify the strength and optimize structure. Based on the draft of design, the first step is to calculate the strength of the front ridge, rear ridge by traditional method. Then, 3D modeling is built in UG and analyze the structure in a commercial Finite Element Method (FEM) tool ANSYS. The stresses distributions of the key components are obtained. Based on the results of first design, the optimization of the structure is optimized according to the given safety factors. The problem can be solved by increas