橡胶O形圈密封结构的有限元分析

建立固体火箭发动机的橡胶O形圈的二维轴对称模型,采用非线性有限元方法计算了O形橡胶圈在库存和工作状态的变形及应力,分析了上下法兰张开间隙、初始压缩量、密封槽口及槽底倒角半径、密封槽宽、密封圈材料、O形圈截面尺寸及工作温度等典型参数对密封性能的影响:上下法兰张开间隙、密封圈的初始压缩率、密封圈材料等典型参数对最大接触压应力影响较大,而密封槽槽口和槽底处倒角对剪切应力影响明显.这些分析为密封结构的优化设计打下了基础;同时探讨O形圈应力分布规律,确定密封圈易受损和失效关键部位,初步确立了固体火箭发动机密封失效准则和失效模式.

Finite element analysis of O-ring seal structure

Applying the theory of nonlinear finite element analysis, the stresses and strain of the elastomeric O-ring seals at storage and working process were analyzed. The factors influencing sealing performance were considered, such as gap between upper and nether flange, initial compressibility, groove width, sealing materials, O-ring section diameter and the work temperature. Results show that the gap breadth, initial compressibility and seals material do great contributions to the maximum contact normal stress, and the groove notch and bottom fillets act upon the maximum shear stress obviously. The analysis lays the foundation of the optimum design of sealing structure. Based on the stresses distribution and the brittle position, the failure mode & criteria were discussed and established.