Seal Failure Analysis of O-Ring Seal Based on Two-Way Fluid-Structure Interaction

Abstract O-ring seal is widely used in pressure system to prevent leakage of the fluid medium. However, in actual situations, excessive pressure of the system and the unreasonable structure usually led to the severe distortion of the O-ring seal, which may result in the seal failure and thus medium leakage. To explore the mechanism of these failures, a two-way fluid-structure interaction (FSI) based analysis was carried out in this paper, where the model of O-ring seal is constructed based on the Mooney-Rivlin hyperplastic constitutive model and the dynamic mesh technique. Through simulations, the stress distribution and the deformation of the O-ring seal under 100 MPa pressure conditions were predicted, verifying the ability of the developed numerical model. On this basis, both one-way and two-way FSI simulations were performed, and the pressure ratio of the sealing surface were compared, which indicates that there is obvious difference between these two types of simulations, the pressure ratio produced by the one-way simulations were higher than that obtained from two-way FSI simulations. Since the two-way FSI takes the sealing surface changing into consideration, to ensure the accuracy, it was used in the follow-up analysis works. By observing the simulated strain and stress distribution, it is determined that seal surface near the two right angles of the limiting plate is the key part prone to medium leakage, which provides a basis for the structural optimization design of the O-ring seal.