Mechanical Property Analysis On Working Equipment Of Hydraulic Excavator

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.