Abstract:In order to test the reliability of underwater sealing structure,Workbench integrated platform was used to compare and analyze the deformation and stress of the O-rings with and without back-up rings.The sealing performance of O-rings with retaining rings in deep water environment was simulated and analyzed.It is found that O-rings with backup rings can effectively prevent squeezing bite when medium pressure is high,and under the same condition,the maximum Von Mises stress can be reduced by more than 20%.When the medium pressure is about 10 MPa,the maximum Von Mises stress of O-ring with backup ring has an obvious inflection point.When the medium pressure is greater than 10 MPa,the stress change of O-ring tends to be gentle,which can avoid seal failure of O-ring caused by damage.In the O-ring structure with back-up ring,the O-ring plays the role of sealing,while the function of the back-up ring is mainly to improve the stress of the O-ring and improve the reliability of the whole sealing structure.This simulation results can explain the principle of O-ring with back-up ring to improve sealing reliability,and provide an effective method for reliability inspection and optimization of underwater sealing structure.