丁基橡胶密封环形状和材料黏弹性对结构密封性能的影响

Effect of viscoelasticity and shape of butyl rubber seal rings on structural sealing performance

为确保橡胶密封结构的可靠性,避免因经验设计带来的密封失效,在考虑丁基橡胶材料的超弹性和黏弹性的基础上,采用数值模拟方法分析密封环的形状和密封材料的应力松弛等因素对结构密封性能的影响.研究结果表明:矩形密封环和梯形密封环的接触应力分布均匀、密封面宽,密封效果优于O形密封环;但压缩量较大时,矩形密封环外角点处较大的剪切应力会造成密封环局部撕裂,进而影响到整体结构的密封性能.短时松弛过程中装配预紧力变化的计算结果与试验测试数据吻合较好.该方法能够预测不同形状密封环在压缩过程中的变形和应力等特征参数,有助于加深了解密封环的密封性能,对同类密封结构设计有一定指导意义.

To ensure the sealing reliability of rubber seal structures and avoid sealing failure caused by the design based on experience, the numerical simulation method is used to analyze the effect on the structural sealing performance, which is generated by the shape of rubber seal ring and the stress relaxation of sealing material. For the analysis, the characteristics of superelastic and viscoelastic of butyl rubber are taken into account. The results indicate that the contact stress distribution is uniform and the area of sealing face is bigger for the seal rings of rectangular or trapezoidal shape, and this types of rings have better sealing effect than the O-shape sealing rings ; however, for the seal rings of rectangular shape, the bigger shearing stress in the corner points of rectangular seal ring can lead to local tear and decreasing the sealing performance of the whole structure further. For the changes of pre-tightening force of assembly in the short-term relaxation process, the calculated results are in good agreement with the experimental ones. The method can predict the characteristic parameters（ such as deformation, stress, and so on） of different shapes of seal rings during pressurization, is helpful for the deep understanding of the sealing performance of seal rings, and useful for the design of the same types of seal structures.