Optimal Design And Reliability Analysis Of Large Spherical Valve

With the fast development of national economy in recent years, hydropower,petroleum processing need more and more spherical valve with high efficiency andlow cost large.At the same time, the requirement of the large spherical valve alsobecomes more and more strict. The structure optimization of the large sphericaldepends on engineering experience for many years. As the main endure pressure partin the large spherical, the plug and body’s structure is very complex, maybe it appearsto stress concentration, discordant deformation, therefore reduces the life-span of thelarge spherical valve and leads to leakage. So it is necessary to adopt advancedComputer Aided Engineering CAE to analysis the data of stress, deformation andoptimize the large spherical valve in order to supply the coach and guide fordeveloping the structure.The thesis is based upon one large spherical plug and body. By using the finiteelement software ANSYS, we can do some research such as static analysis, structuraloptimization and fatigue analysis. The main content are as following:1. Creating finite element model of large spherical plug and body, we cananalyse the stress and deformation to get the stress data and distributing, and finallyfind out the weakness position.2. We take the quality and hardness of large spherical plug and body as restrictcondition, take the most stress and deformation as target value and take dimensions asvariable. Combined with the sensitive analysis and the Multi-objective optimizationof Pareto, we find out the reasonable size and position of stiffener to improve thestress disposition and uniform distribution. Therefore the structure of sphericalbecomes more safety and economic.3. Analysing the reliability of the improved plug and body’s structure, we can getthe fatigue data of life, damage, safe safety factor and so on. We find out the weakposition and evaluate the safety of the large spherical valve. The result indicates thatthe optimized spherical is safety and reliable under the work pressure, and can meetthe design requirement.