Sealing performance of O-ring under coupled thermo-mechanical conditions

Abstract. To resolve the sealing deficiencies of actuator O-rings under cryogenic conditions and high-pressure environments, this study systematically analyzes the sealing performance of elastomeric O-rings, considering the hyperelastic properties of rubber materials and the nonlinear characteristics of contact friction. A two-dimensional axisymmetric finite element model was developed in ANSYS to analyze the effects of temperature, oil pressure, retaining rings, and O-ring dimensional variations on sealing performance. The results indicate that the combined use of a retaining ring and an O-ring enhances the sealing contact pressure of the O-ring, effectively preventing extrusion between the O-ring and the cover plate gap. Under cryogenic conditions (−55 °C), the interface contact pressure between the cover plate and O-ring exhibits a 1.9 MPa reduction relative to ambient temperature (25 °C), consequently amplifying the potential for sealing failure. Furthermore, dimensional analysis reveals that increasing the O-ring cross-sectional diameter enhances the interface contact pressure, thereby improving the sealing efficacy. From a safety and reliability perspective, it is recommended that the O-ring diameter be no less than 1.50 mm, with a maximum allowable assembly gap of 0.02 mm. These findings provide a methodological framework and theoretical guidance for the design and optimization of actuator sealing systems with different O-ring materials, sealing structures, and working environments.