Structure Optimization And Reliability Analysis For Large-calibred Gate Valve Body

Large-calibred gate valve (DN is 350～1200mm) in the water and industrial pipelines are widely used. Valve body is the most important one of the components of large-calibred valve, and its structure and parameters have important implications on the overall performance of the valve. As a result of large-calibred valve body constrainted by structural length, and the cavity which contains flat flashboard usually round or oval shaped container, so it is difficult to use the theoretical formula for the strength and stiffness analysis. Therefore, how to use the advanced CAE(Computer Aided Engineering) technology for strength and stiffness analysis, optimization design and reliability assessment of the large-caliber valve body structure, further improvements to provide a basis and guidance for such structures, that has become a common concern topic of the industry.This paper has an optimization analysis and reliability research on a large-calibred valve body structure of one factory, with the method of CAE and advanced design technology. The research content outline is as follows:1. Based on the ANSYS Workbench Environment integrating development platform environment, the parameterized model of large-calibred gate valve body was established, based on the boundary conditions of overall structure, the static valve body was analyzed under test conditions imposed load. The distribution and stress of valve was researched.2. From the perspective of security and economy, taking the stress at the maximum equivalent stress concentration point as target function with the geometric mass, stiffness constrains and the principal dimensions of the valve body as the design variables.The valve body structure design was carried out on how to improve the structure of valve body to reduce the stress concentration and optimize the structural size and location of stiffeners. The optimum size of the valve body was obtained, and combined with the maximum equivalent stress sensitivity analysis, some instructive suggestions for design of the kind valve body are provided. The results showed that the maximum equivalent stress of the optimized valve body structure was reduced by 18.8 percent significantly. and the distribution of stress is more reasonable. The research method has higher efficiency and accuracy.3. Based on the structural reliability theory, taking the valve structure size, materials property and load as the random input variable, the stochastic Monte Carlo finite method which bases on Latin ultra cubic sampling be used to achieve the cycle strength reliability analysis of the optimized valve body structure by the reliability analysis PDS module of ANSYS software platform. The strength reliability sensitivity analysis effect of the design parameters was showed intuitively, and the dependability of the optimized structure and the feasibility of the optimum design is verified ultimately.