Considering the limitation of computational capacity, a new finite element solution is used to simulate the welding deformation of the side sill of railroad car＇ s bogie frame based on the local-global method. Firstl...Considering the limitation of computational capacity, a new finite element solution is used to simulate the welding deformation of the side sill of railroad car＇ s bogie frame based on the local-global method. Firstly, a volumetric heat source defined by a double ellipsoid is adopted to simulate the thermal distributions of the arc welding process. And then, the local models extracted from the global model are computed with refined meshes. On these bases, the global distortions of the subject studied are ascertained by transferring the inner forces of computed local models to the global model. It indicates that the local-global method is feasible for simulating the large welded structures by comparing the computed results with the corresponding actual measured values. The work provides basis for optimizing the welding sequence and clamping conditions, and has theoretical values and engineering significance in the integral design, manufacturing technique selection of the bogie frame, as well as other kinds of large welded structures.展开更多
Wire arc additive manufacture(WAAM) is a new technique to fabricate large-scale complex aluminum alloy components.However, the performance of the parts is critically influenced by residual stresses and deformation. A ...Wire arc additive manufacture(WAAM) is a new technique to fabricate large-scale complex aluminum alloy components.However, the performance of the parts is critically influenced by residual stresses and deformation. A sequentially thermal-mechanical coupled model of residual stress and deformation for aluminum alloy WAAM parts was established based on commercial FE software ABAQUS. The temperature field was calculated by the moving heat source(MHS) method. The temperature function was obtained according to the distribution of the peak temperature. Furthermore, the MHS method and segmented temperature function(STF) method were used to calculate the residual stress and deformation. The results show that the STF method satisfies both the efficiency and accuracy requirements. 1-segment, 3-segment, and 5-segment STF methods can shorten the time for mechanical analysis by 91%, 79%, 63%, respectively.The error of the residual stress and deformation are all less than 20%. STF method provides an effective way to predict the residual stress and deformation of large-scale WAAM parts.展开更多
文摘Considering the limitation of computational capacity, a new finite element solution is used to simulate the welding deformation of the side sill of railroad car＇ s bogie frame based on the local-global method. Firstly, a volumetric heat source defined by a double ellipsoid is adopted to simulate the thermal distributions of the arc welding process. And then, the local models extracted from the global model are computed with refined meshes. On these bases, the global distortions of the subject studied are ascertained by transferring the inner forces of computed local models to the global model. It indicates that the local-global method is feasible for simulating the large welded structures by comparing the computed results with the corresponding actual measured values. The work provides basis for optimizing the welding sequence and clamping conditions, and has theoretical values and engineering significance in the integral design, manufacturing technique selection of the bogie frame, as well as other kinds of large welded structures.
基金supported by the National Key Technologies R&D Program (Grant No. 2018YFB1106000)Innovation Funds of China Academy of Launch Vehicle Technology (CALT) for Universities (Grant No.CALT201709)Tsinghua Grants for Autonomous Research。
文摘Wire arc additive manufacture(WAAM) is a new technique to fabricate large-scale complex aluminum alloy components.However, the performance of the parts is critically influenced by residual stresses and deformation. A sequentially thermal-mechanical coupled model of residual stress and deformation for aluminum alloy WAAM parts was established based on commercial FE software ABAQUS. The temperature field was calculated by the moving heat source(MHS) method. The temperature function was obtained according to the distribution of the peak temperature. Furthermore, the MHS method and segmented temperature function(STF) method were used to calculate the residual stress and deformation. The results show that the STF method satisfies both the efficiency and accuracy requirements. 1-segment, 3-segment, and 5-segment STF methods can shorten the time for mechanical analysis by 91%, 79%, 63%, respectively.The error of the residual stress and deformation are all less than 20%. STF method provides an effective way to predict the residual stress and deformation of large-scale WAAM parts.
