【作者】 李金晓；

【导师】 杨茹萍；

【作者基本信息】 河南科技大学 ， 工程力学， 2010， 硕士

【摘要】 工作装置是液压挖掘机的主要构件,其结构是否合理将直接影响到液压挖掘机的工作性能,而有限元方法作为一种非常实用、可靠的结构分析方法,能够快速、准确地计算出构件的受力和变形情况。本文以洛阳一拖神通公司生产的WLY 3.5-70型液压挖掘机为研究对象,利用大型有限元分析软件ANSYS对其工作装置进行建模并进行了强度、变形和模态分析。本文主要将就以下几方面进行阐述:1.利用ANSYS软件分别建立工作装置三个组成部件(动臂、斗杆和铲斗)各自的实体模型,针对三种典型工况,将三组成部件合并归档,得到相应的工作装置整体三维模型,再根据实际情况确定所用单元的类型和材料属性,然后进行网格划分,得到三种工况下工作装置整体三维有限元模型。2.根据三种典型工况下的受力情况,对工作装置施加边界约束和载荷,求解后得到相应的应力、位移云图。应力的最大值主要分布于不同部件相铰接的部位,如斗杆与动臂连接处、斗杆液压缸支座处及动臂与动臂液压缸相连接的轴套处等,这是因为在铰接处出现了局部应力集中现象,可以通过改变铰接处的局部尺寸来减小应力集中。3.在三种典型工况下,对工作装置进行有限元模态分析,得到系统前14阶的固有频率和振型。工况一和工况二的第8、11、13阶振型以及工况三的第8、9、10阶振型最大位移位置出现异常,说明在这些振型所对应的频率下,最大位移处易发生破坏,可以通过增加板厚或者增设加强筋来增强结构的整体刚度。更多还原

【Abstract】 The working equipment is the main components of a hydraulic excavator. The reasonability of the structure will directly affect the working performance of the hydraulic excavator. As a very practical and reliable way of structure analysis, the finite element method can quickly and accurately get the stresses and the displacements of the structural parts. Taking the WLY3.5-70 backhoe hydraulic excavator made of Luoyang Yituo Shentong Machinery Limited Company for example, the stiffness, deformation and modal analysis about the working equipment will be carried on in this study by using the finite element software ANSYS. The following aspects will be described in this paper:1. The solid modeling of the three parts of the working equipment (the boom, the arm and the bucket) is established by using the finite element software ANSYS. Merge the three parts according to three kinds of typical working conditions, the 3-D model of the whole working equipment is established. Then determine the element type and the material properties according to the actual situation. After dividing the model into finite elements, the 3-D finite element model of the whole working equipment under three kinds of typical working condition is established.2. Impose boundary constraints and loads to the working equipment according to the force situation of the three kinds of typical working conditions. The corresponding stress and displacement contour diagrams are obtained after calculation. The maximum value of the stress mainly distributed in the articulated parts, for example the conjunction areas of arm and boom, the bearing of the arm cylinder, the sleeve of the boom cylinder and boom. It is because of the local stress concentration of the conjunction areas. We can reduce the stress concentration by changing the local dimension of the conjunction areas.3. The finite element modal analysis is performed to the working equipment under three kinds of typical working conditions. The natural frequencies and mode shapes of the first 14-order are obtained. The vibration mode of the 8-order, 11-order, 13-order under condition 1 and condition 2 is abnormal, the 8-order, 9-order, 10-order under condition 3 have the same problem. This shows that it is prone to damage at the place where the maximum displacement occurred. The overall stiffness of the structure can be enhanced by increasing the board thickness and adding the stiffened plate.更多还原