Theoretical and Experimental Measurement of Stiffness Parameters of Pneumatic Butterfly Valves
At present, there are two ways to confirm the stiffness parameters of pneumatic butterfly valves: theoretical analysis and experimental measurement. For the pneumatic butterfly valve with simple shape, theoretical analysis can use analytical method or graphical method to calculate the approximate solution, but for the pneumatic butterfly valve with complex shape, it is difficult to calculate its stiffness. Moreover, the analytical solution obtained from theoretical analysis does not consider the impact of the pneumatic butterfly valve capsule wall data on the stiffness. Although the experimental measurement can obtain the practical stiffness, the experimental process requires samples, and the adjustment of the experimental process parameters is relatively difficult, which brings great difficulties to the design of the pneumatic butterfly valve, not only prolonging the design cycle, but also increasing the research and development costs [4]. Fortunately, with the rapid development and application of computer aided engineering, the application of simulation analysis to stop the design and optimization calculation of pneumatic butterfly valves has gradually become one of the indispensable effective methods. Analyzing the stiffness of pneumatic butterfly valves with finite element method, not only considers the impact of capsule wall data on the stiffness, but also can better calculate the stiffness of pneumatic butterfly valves with complex shapes. Since the 1990s, the research on simulation and imitation of pneumatic butterfly valve system has become a hot spot. Many foreign scholars have carried out a series of simulation studies on pneumatic butterfly valves using finite element method and obtained many important conclusions [5-6]. The research on pneumatic butterfly valve in China began in 1957, when it was limited to pneumatic butterfly valve for vehicles. The preliminary research on the theory of pneumatic butterfly valve was stopped, and some experience was accumulated in theory and experiment.