充气密封的非线性有限元分析

Nonlinear Finite Element Analysis of Inflatable Seals

基于大型非线性有限元处理软件MSC.Marc,考虑结构的材料非线性、几何非线性和接触非线性,建立了充气式气囊密封的轴对称有限元模型,对其充气密封机制进行了分析,得到了唇口法向接触应力的分布规律;讨论了充气压力、密封压力与充气压力比、轴径对法向接触应力的影响。结果表明,法向接触应力是实现有效密封的关键,该应力随充气压力和轴径的增大而增大;被密封介质压力使得靠近介质一侧的接触应力减小而另一侧的接触应力增大;最大等效Cauchy应力主要集中于气囊壁内的增强纤维层,且随充气压力的增大而增大;为保证密封的效果和密封的可靠性,必须选择合适的结构型式(包括气囊和密封间隙等)和充气压力;利用有限元软件MSC.Marc进行充气密封气囊的仿真设计是可行的。

Taking nonlinear material property, geometrical deformation and contact condition into account, an axisymmetric finite element model of inflatable seal was developed with the help of the nonlinear finite element software MSC. Marc. The seal mechanism was analyzed and normal contact stress distribution along seal bead was obtained. The influence of pneumatic pressure, sealed pressure and axial diameter on normal contact stress was discussed. Results show that normal contact stress is critical to assure a safety seal, which increases with the increase of the pneumatic pressure and axial diameter. In contrast with the ease without sealed pressure, the normal contact stress on the side of sealed media is larger than that on the other side. The maximum of equivalent Cauchy stress is found in the reinforced fibre layer in the wall ,which increases with the increase of pneumatic pressure. Good choice in product configuration and pneumatic pressure should be done to achieve a safety and reliable seal. It is feasible to design inflatable seal product with the help of finite element software.