3D Nonlinear Contact FEM Analysis of U-ring Seal Structure

The U-ring reciprocating seal structure with high pressure was taken as research object; the nonlinear contact characteristics and failure mechanism of U-ring seal were analyzed. Finite element model was build through segmentation and sweep methods, Mooney-Rivlin model was selected to characterize the rubber material, the Generalized Lagrange Multiplier Method were designed as contact algorithm. Based on LS-DYNA software, the 3D nonlinear dynamic simulations of U-ring seal structure were realized under different conditions. The results shows that the maximum contact stress steady increased with the growth of medium pressure, relative velocity, and friction coefficient, the top of inner lip and the circle of bottom hole were the main sites of contact stress concentrated on, the reverse velocity of valve stem is the main factor impact too large contact stress and seal damage. The simulation conclusions were verified by comparing the characteristics of actual seal failure.