Elastic-plastic Contact Calculation and Sealing Performance Analysis of Metal Sealing Ring

doi:10.12382/bgxb.2024.0371

Abstract

Abstract:

Metal sealing rings are widely used in various mechanical products,mainly achieving the sealing effect through the elastic-plastic contact deformation of rough surfaces.The traditional finite element simulation method for the microscopic contact of rough surfaces has the low computational efficiency and difficult convergence of elastic-plastic contact deformation.An elastic-plastic contact calculation method based on coupled finite element and boundary element methods is proposed.A macro-finite element model of metal ring seal structure is established to accurately solve the contact stress distribution of sealing surfaces,and the micro-morphology of sealing surfaces is established.A boundary element method for elastic-plastic contact calculation with the superposition of residual deformation and residual stress fields is proposed by taking the macroscopic contact stress distribution as the boundary condition.The boundary element method is used to solve the contact state of sealing surfaces under elastic-plastic deformation.Meanwhile,the micro-contact equivalent modeling method of sealing surfaces is verified,and compared with the finite element simulation method for the microscopic contact of rough surfaces.The results show that the calculational accuracy of the finite element-boundary element coupling simulation method is equivalent to that of the finite element method,but its calculational efficiency is improved by nearly 8 times.The leakage channels of sealing surfaces are solved by the four-connection grid model and used as the evaluation index of sealing performance.The effects of material parameters,contact stress,surface roughness and rough surface parameters on the sealing performance of metal sealing ring are systematically studied.A sealing test equipment is built to measure the leakage rate of metal sealing ring,and the variation law of the actual leakage rates of metal sealing ring with the normal load is obtained.The simulated results are consistent with the experimental trend.

Key words: metal sealing ring, finite element, boundary element, contact calculation, leakage channel

CLC Number:

O344

WANG Kai, ZHENG Mengwei, GONG Hao, LIU Jianhua, ZHAO Youlei, LIU Shaoli. Elastic-plastic Contact Calculation and Sealing Performance Analysis of Metal Sealing Ring[J]. Acta Armamentarii, 2025, 46(6): 240371-.

Figures/Tables 30

Fig.1 Copper gasket sealing structure

Fig.2 Flowchart of contact calculation and sealing performance analysis of metal sealing ring based on coupled finite element-boundary element method

Fig.3 Finite element model of copper gasket sealing structure

Table 1 Material properties of different materials

材料	屈服强度/ MPa	弹性模量/ GPa	切线模量/ MPa	泊松比
30CrMnSiA	835	206	2553	0.30
TC11钛合金	900	107.8	1 814	0.34
T2紫铜	70	108	868	0.35

Fig.4 Boundary condition setting and force loading

Fig.5 Pressure distribution cloud chart of copper gasket contact surface

Fig.6 Pressure distribution curve of copper gasket sealing surface

Fig.7 Approximate treatment of macroscopic sealing surface

Fig.8 Micro-morphologies of surfaces with different roughnesses

Fig.9 Equivalent simplification of contact problem

Fig.10 Finite element models of rough surface contact before(left) and after(right) equivalence

Table 2 Material properties before and after equivalence

等效前后		弹性模量/ GPa	泊松比	屈服强度/ MPa	切线模量/ MPa
等效前	表面1	120	0.3	1200	10000
等效前	表面2	120	0.3	500	10000
等效后		60	0.3	500	10000

Fig.11 Comparison of elastic-plastic finite element calculation results before(left) and after(right) equivalence

Fig.12 Contact calculation diagrams of finite element method(left) and finite element-boundary element coupling method(right)

Fig.13 Calculated results of contact gap distribution obtained by finite element method(left)and finite element-boundary elementcoupling method(right)

Fig.14 Four-connection grid model

Fig.15 Contact state demonstration matrix

Fig.16 Relationship between yield limit of metal sealing ring and contact area ratio

Fig.17 Contact states of sealing surfaces under different yield limits of metal sealing rings

Fig.18 Relationship between elastic modulus of pressed component and contact area ratio

Fig.19 Contact states of sealing surfaces under different elastic moduli of pressed component

Fig.20 Influences of different contact pressures on contact area ratio

Fig.21 Contact states of sealing surfaces under different contact pressures

Fig.22 Influences of different surface roughness on contact area ratio

Fig.23 Contact states of sealing surfaces under different surface roughnesses

Fig.24 The leakage channels of sealing surfaces with different surface textures

Fig.25 Schematic diagram of sealed experimental platform

Fig.26 Experimental tooling model

Fig.27 Experimental site

Fig.28 The relationship between the normal load on the gasket and the leakage rate

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