The LG952 Lift Arm Welding Residual Stress And Static Strength Analysis

Loaders is used widely, but its work condition is very bad and work process is not presupposed. So the strength of lift arm assembly should be enough strong to meet them. The lift arm assembly consists of lift arms,cross member and the support of the bell crank, all of these are connected by welding. After the effecting of welding and the welding temperature, the physical properties and mechanical properties of the metal around the weld seam have changed, meanwhile some welding residual stress and welding crack arose in the welding position. Under cyclic loading and impact loading, the welding position will be damaged easily.Therefore, it is necessary to analyze the welding residual stress of some key region under typical case in the construction machine's design. We can obtain the stress variation regular and the stress curve by using the finite element method combined with relating software. All these will be helpful for us.The produce of welding residual stress has closed relation with welding temperature, so we can obtain the value and variation regular of welding residual stress by analyzing the welding temperature field in the ANSYS. Welding temperature field analysis is thermal analysis virtually.Thermal analysis consist of steady thermal analysis,transient thermal analysis and some coupling analysis just like thermal-struc coupling analysis,thermal-fluid coupling analysis,thermal-magnetc coupling analysis and thermal-elect-struc2 coupling analysis. This paper imitate the welding process between lift arms and cross member by ANSYS,as the welding temperature and the thermal load is varied with time, so it is transient thermal analysis.This paper calculates the welding residual stress between lift arms and cross member by the ANSYS thermal-structure coupling analysis block in order. Firstly, this paper imitate the welding process between through the finite element model of lift arm assembly by ANSYS, by doing this we can get the temperature field of last time. Secondly, the thermal analysis should be transformed to structure analysis, and the temperature field should be put on the nodes of finite element model as thermal load, meanwhile boundary condition and displacement constraint also should be put on the finite element model. Finally, we obtain the value and variation regular of welding residual stress.The static strength analysis block of ANSYS can calculate the displacement,strength and strain under the fixed load. The stress on the parts of working equipment varies with the operating mode, and this paper carries out the static strength analysis under the operating mode(3),namely the symmetry horizontal force and vertical force are put on the working equipment synchronously.Under the symmetry horizontal force and vertical force combined operating mode, the forces of each hinge joint can be calculated. According with the results the boundary condition and displacement constraint should be put on the finite element model. Finally, we obtain the value and variation regular of welding residual stress.After finishing analyze, this paper samples out 8 nodes from the finite element model. By adding the value of welding residual stress to the strength value under the operating model an another value data will be gotten. Comparing the results from the finite element analysis and experiment, the rationalities of this model and the dealing methods were testified.