Study On Shrinkage And Deformation Of Longitudinal Longitudinal Welded Laminates Of Multi - Layer Wrapped High Pressure Vessel

With the continuous development of modern industries, the applications of pressure vessels are becoming wider in production technique fields. According to the manufactural methods of pressure vessel cylinders, pressure vessels can be categorized as two types of constructions:monoblock and multilayer. Considered that multilayer pressure vessels have such outstanding advantages as easy to manufacture, production security and economic benefits compared with monoblock pressure vessels, multilayer pressure vessels, especially for high pressure vessels, are utilized more. In order to make multilayer pressure vessels fit various production conditions, meet the needs of large scale production and assure their safe operation, the research on multilayer pressure vessels is of important significance and practical value.Integrated multilayer wrapped high pressure vessel colligates the advantages of the present multilayer pressure vessel constructions, and is a type of comparatively ideal multilayer pressure vessel construction. However, the welding deformation etc of longitudinal seams in the layer during its manufactural process isn’t clear, which makes the prestress in the inner cylinder and layers impossible to be utilized up to now. In allusion to integrated multilayer wrapped high pressure vessel, theoretical research, numerical simulation analyses and experimental investigation on its welding deformation of longitudinal seams in the layer during its manufactural process were made in this paper. The main contents are as follows:1. By comparison and analyses of the welding of longitudinal seams in the layer and the free welding in common steel structures, based on the characteristics of manufactural process and the related influence factors of welding deformation of longitudinal seams in the layer for integrated multilayer wrapped high pressure vessel, the functional expression for the welding deformation of longitudinal seams in the layer was put forward, and the three main factors which affect the welding deformation were ensured as circumferential prestress in the layer, layer thickness, cross section area of the welding seam.2. By using ANSYS finite element analysis software, the numerical simulation analyses on longitudinal seams in the layer were made for the integrated multilayer wrapped high pressure vessel, which was carried out respectively according to the three main factors which affect the welding deformation such as circumferential prestress in the layer, layer thickness, cross section area of the welding seam. The numerical simulation analysis results showed that, (1) the bigger the circumferential prestress in the layer was, the smaller the transverse shrinkage deformation of longitudinal seam in the layer was, and the smaller the area of the welding deformation was; (2) the thicker the layer was, the smaller the transverse shrinkage deformation of longitudinal seam in the layer was, and the smaller the area of the welding deformation was; (3) the larger the cross section area of the welding seam was, the bigger the transverse shrinkage deformation of longitudinal seam in the layer was, and the larger the area of the welding deformation was.3. Welding deformation and its cooling process of longitudinal seam in the layer during the manufactural process of several sections of integrated multilayer wrapped high pressure vessel with an inner diameter of 500mm were measured in the laboratory by using DH3816 Static Strain Testing Analytical System and the testing equipment of welding deformation. By comparison and analyses of the experimental results and the numerical simulation analyses, the correctness of the numerical simulation analyses was validated, and the empirical equation of transverse shrinkage deformation of longitudinal seam in the layer with the layer material of Q245R and the welding method of handwork was obtained by the theoretical analysis and the experimental investigation.The research results of the welding shrinkage deformation of longitudinal seam in the layer of integrated multilayer wrapped high pressure vessel laid good foundations for analyses, calculations and applications of transverse shrinkage deformation of longitudinal seam in the layer during its manufactural process, simultaneously which has a certain guidance significance and practical value for its design and manufacture and assuring its manufactural quality.