Aviation hydraulic joint leakage prediction with normal-tangential contact mechanics model

The sealing performance of flared aviation hydraulic pipe joints directly determines whether the aircraft can operate safely. Accurately analyzing the contact forces at the joints and revealing the mechanism through which they affect the sealing performance are essential for resolving leakage failures. In this study, a new leakage prediction model for flared aviation hydraulic pipe joints is developed based on a contact mechanics model that accounts for both normal and tangential forces acting on the sealing interface. The average separation of the interface was redefined from variations in the void volume of rough surfaces, and its relationship with the leakage rate was derived through contact deformation, enabling prediction of the joint's leakage behavior. The results demonstrate that the proposed model considers the impact of tangential forces on interfacial sealing, improving leakage rate prediction accuracy by 28.5%. This improvement is mainly attributed to accounting for the influence of tangential forces on the average separation of the interface and the real contact area. This work provides insight into the leakage mechanism at metal-metal sealing interfaces and offers theoretical guidance for analyzing sealing performance and optimizing assembly process parameters of hydraulic pipe joints.