径向金属密封唇部结构接触力学研究

Study on Contact Mechanics of Radial Metal Seal Lip Structure

由于初始过盈量和介质压力的作用,井下流量控制阀径向金属密封唇部的应力和应变梯度变化很大,很容易发生塑性变形。为研究径向金属密封唇部接触力学行为,提出径向金属密封唇部的圆弧结构,基于接触力学建立径向金属密封唇部轴对称结构的圆弧-平面接触模型,得出径向金属密封唇部结构接触力学参数的理论关系式,并基于有限元方法进行验证。径向金属密封唇部接触力学参数的理论解与数值解相符,接触宽度、最大接触应力、初始过盈量和平均接触应力的平均相对误差分别为8.86%、6.96%、8.88%和4.33%,满足工程设计要求。研究表明:径向金属密封唇部的最大接触应力与初始过盈量、径向金属密封唇部径向厚度和轴向厚度成正比,与径向金属密封唇部圆弧半径成反比,因此可通过增加初始过盈量、径向金属密封唇部径向厚度和轴向厚度来增加径向金属密封唇部的最大接触应力。研究结果为井下流量控制阀径向金属密封的设计提供了理论指导。

Due to the effect of the initial interference and medium pressure, the stress and strain gradient of the radial metal seal lip in the interval control valve change greatly, which is easy to cause plastic deformation.In order to study the contact mechanics behavior of the lip of radial metal seal, the circular arc structure of the radial metal seal lip was proposed.Based on contact mechanics, the circular plane contact model of the axial symmetrical structure for the radial metal seal lip was established.The theoretical relationship of the contact mechanics parameters for the radial metal seal lip structure was obtained, and the verification was carried out based on finite element method.The theoretical solution of the contact mechanics parameters for the radial metal seal lip is in accordance with the numerical solution.The average relative errors of contact width, maximum contact stress, initial interference and average contact stress are 8.86%,6.96%,8.88% and 4.33% respectively, which meets the engineering design requirements.The research result shows that the maximum contact stress of the radial metal seal lip is directly proportional to the initial interference, the radial thickness and axial thickness of the radial metal seal lip, and inversely proportional to the arc radius of the radial metal seal lip.Therefor, the maximum contact stress of the radial metal seal lip can be increased by increasing the initial interference, the radial thickness and the axial thickness of the radial metal seal lip.This research result provides the theoretical guidance for the design of the radial metal seal in the interval control valve.