Finite element analysis of lens gasket sealing ring The working state of the 18-inch lens gasket sealing ring and the matching flange is simulated by the finite element method, and the stress distribution of the two is analyzed. Since the flange-seal ring system is a strictly axisymmetric structure and is mirror-symmetrical about the mid-plane of the seal ring, the finite element analysis can be performed only for the 1/2 radial section, as shown in Figure 2. While improving the modeling efficiency, it also greatly saves time. The mesh size specified in the model adopts the method of mapping and dividing, and the mesh is refined near the contact surface. Table 2 Parameter Symbol Notes Table Symbol Notes Di Internal diameter of flange or flange face dD Bearing model seal diameter design value d′D Seal diameter intermediate calculation value d1 Seal ring inner diameter d2 Seal ring outer diameter d5 The outer diameter of the flange inner bevel Diameter h1 The height of the sealing ring at d1 hD The height of the sealing ring at dD h2 The height of the sealing ring at d2 x The distance between the end faces of the two flanges r The rounding value of the spherical radius of the sealing ring r′ The calculated value of the spherical radius of the sealing ring . The working principle of the metal seal determines that the hardness of the sealing ring should be slightly lower than that of the flange, so the lens pad and the flange are made of 316 stainless steel and 12Cr2Mo1 [4-5] respectively. The elastic modulus of 316 stainless steel is (2.0105) MPa; 12Cr2Mo1 is a low-alloy hot-strength steel, and the elastic modulus is (2.06105) MPa; the yield strength of both is 310 MPa. When creating the sealing surface contact pair, use the CONTA172 element for the contact surface on the lens pad and the TARGE169 element for the target surface on the flange. The internal pressure of the model is 34.5MP, which acts on the sealing ring, the inner surface of the flange and the inside of the contact point between the two. A concentrated axial load of 6210kN is applied to the inclined shoulder of the flange, and this working preload is calculated according to the relevant regulations of ASME [6]. Due to the mirror symmetry of the model, the vertical displacement of the center line of the sealing ring is limited. Model loading and boundary conditions are shown in Figure 3. The stress distribution of the 18-inch lens pad is shown in Figure 4. The maximum equivalent stress value is 241.5MP, which is now near the contact point. The size of the contact pressure determines the final sealing effect. In theory, when the contact pressure is greater than the pressure that needs to be sealed, a safe seal can be formed. The contact pressure between the flange and the sealing ring is 383.0MP, as shown in Figure 5.