Finite Element Analysis Of Several Typical Expansion Joints

With the development of industrial technology, expansion joints gradually trend to large-scale development. Expansion joints specifications in the existing standard GB16749can not meet the needs of industrial production, finite element analysis of large-scale expansion joint become necessary design tools. The thesis focuses on finite element analysis of thick-walled U-shaped expansion joints on pressure vessels and hinged expansion joint in pipelines. The main contributions are as follows:1, in the analysis of thick-walled expansion joint, conventional design method and finite element analysis design method are used. Conventional design on DN4216mm thick-walled expansion joint is based on GB16749standard. The SHELL51unit and PLANE82unit were adopted for finite element analysis design and stress calculation results were checked based on JB4732. Comparing the results of finite element analysis with SHELL51unit to results of the conventional design, there is a maximum difference of8.1%. Moreover, stresses of the finite element results are smaller than that of conventional results. Therefore, the conventional design of DN4216mm expansion joint is somewhat conservative. By comparing the stress results of finite element analysis, in which SHELL51unit and PLANE82unit were separately adopted, there is not much difference between the finite element analysis of two unit types.2, structure parameters optimization design was carried out on thick wall expansion joint of pressure vessels. In order to satisfying two kinds of conditions including pressure loading condition and axial displacement loading condition at the same time, two independent models of optimization were created, total volume decreased by31.0%after optimized.3, nonlinear finite element analysis was carried out on the hinged expansion joint structure and JB4732standard was based on to check the structure components of expansion joint. The design of DN2200universal hinged expansion joint can meet the design requirements.4, comparation between two types of universal ring was carried out under the same mass, it is found that the performance of square ring is better than that of circular ring. It is also proved gussets of square gimbal ring are not beneficial to axial stiffness of square ring.