Research On Autofrettage Technology Of Interference Fit Of Ultra-high Pressure Vessel

With the rapid development and transformation of society,modern industry not only has higher and higher requirements for the bearing capacity of high-pressure vessels,but also attaches more and more importance to the environmental problems that may be caused by manufacturing and production.This puts forward higher requirements for the structural design,manufacturing process and environmental protection of the pressure vessel.How to effectively improve the carrying capacity and safety of superpressure vessels is a global important issue.This paper consults relevant literature and considers various application theories of pressure vessel design,including multilayer shrink fit technique,autofrettage technique,and elastoplastic theory.A method of combining thermal autofrettage technique with multilayer shrink fit technique is proposed.The thermal autofrettage technique creates a favorable residual stress in thick-walled cylinders by applying a stable temperature gradient on the inner and outer walls,which is very green,safe and environmentally friendly.Easy.The multi-layer shrink fit technology is to fit a pair of inner and outer cylinders with an interference amount through a heat jacket or strong assembly to generate favorable stress on the contact surface.The combination of the two technologies further homogenizes the stress distribution of the cylinder wall during work,which improves the bearing capacity of the pressure vessel.In this paper,double-layer thick-walled cylinders are selected as the research object,and theoretical research and numerical simulation methods are used to carry out basic research around several important stages of temperature gradient,so that the inner and outer cylinders are thick-walled cylinders with temperature gradient and interference fit.The application provides theoretical support.The research mainlyincludes the following aspects: First,the optimal interface radius formula,the maximum working internal pressure,and the optimal interference amount are deduced based on the elastic theory,iso-strength theory,and other principles and processes of the double-layer shrink fit.The calculation formula of thermal autofrettage technique,based on ideal elastoplastic materials,using the von Mises yield criterion to obtain the formula for the temperature gradient process of a single-layer thick-walled cylinder,and the single-layer thick-walled cylinder after unloading the temperature gradient Internal residual stress distribution.The radius of the inner and outer cylinders is determined according to the optimal conditions of the theoretical double-layer shrink fit cylinder,and then the calculation formula of the inner and outer cylinders with autofrettage temperature gradient and then the shrink fit is discussed.Provide theoretical support for maximizing the carrying capacity of the cylinder.Analytical solutions of each stress component and equivalent stress were calculated by MATLAB in the above process,and the data were sorted and plotted by ORIGIN.Using ANSYS Workbench,the double-layer thick-walled cylinder was modeled and the simulation analysis of the autofrettage process was performed.The theoretical values obtained from theoretical calculations are compared to verify the accuracy and reliability of the theoretical analysis.