Study On Numerical Method Of Strength Analysis Based On Coupling Method Of Welding Residual Stress And Service Load

Welded structures are extensively used in various areas of the national economy because of its uncomplicated, cost effective, flexible and reliable. And the design of welded structures is crucial to the safety and reliability of the whole system. However, the magnitude and distribution of stresses and deformation resulting from joining represent an important consideration in the static load carrying capacity of welded structures. Thus, there are great realistic meaning and practical value by studying on numerical method of strength analysis considering welding residual stress for the design of welded structure and welding process. A numerical method of strength analysis based on coupling method of welding residual stress and service load was investigated through the combination of the finite element simulation, the theoretical analysis and the test results in this paper. The method was described and validated using a structural strength application that was based on a main air reservoir. It is considered that the proposed methodology has the potential for use as a generally applicable method for welded structures design.The mechanical properties of base metal and welded joints about Q235at room temperatures were tested by tensile strength tests in this paper. And the microstructure distribution of the welded joints of air reservoir was revealed based on microstructure characterizing by using optical microscopy and microhardness tests. The microstructure distribution from the base metal via the heat affected zone to the weld seam is as following:(F+P)â†'(F+P)â†'20%(F+P)+80%B. Then constitutive equation of the elastic plastic field and function database of base metal and welded joints about Q235were built for numerical simulation of welding process. Based on SYSWELD, a finite element model (FEM) was established to provide the technical base for simulating residual stress field of welded joints calculated the effect of phase transformation. The application of the model to the case of welded joints was verified by X-ray method of residual stress measurement and comparison of microstructure and macrograph.According to above FEM, the welding process of the main air reservoir were simulated to obtain welding residual stress and strain field. An auto-transformation tool for data transformation of residual stress and strain was created by Matlab. And the format of mesh was transformed by Hypermesh. Then a FEM of strength analysis based on coupling method of welding residual stress and service load was built in ANSYS combined with material database above. Then based on analysis method of linearizing stress, the FEM was used to analyze the strength data of the air reservoir with and without welding residual stress. The comparative analysis showed that the positions of structural weakness were transformed and the static load carrying capacity was reduced by welding residual stresses. From this study, it can be concluded that residual stresses must be included in strength design of welded structures and the FEM provided in this paper is a valid calculation approach.