Rubber O-ring seal in high-pressure hydrogen system swells due to hydrogen absorption and dissolution after direct exposure to high pressure and high purity gaseous hydrogen. Few works are available in literature on swelling effect on seal performance. A constitutive model of rubber hyperelasticity coupled with hydrogen-induced strain was proposed. Finite element software ABAQUS and user material subroutine (UMAT) program were used to establish a finite element analysis model of hydrogen-swelled rubber O-ring seal in high-pressure hydrogen. Effect of swelling on O-ring seal performance was further studied with the developed model. Results showed that seal contact stress was increased by swelling

which is beneficial to maintain seal performance. However

hydrogen swell increased height and area of O-ring cross section and Mises stress of O-ring

which may make it more susceptible to crack and less reliable of seal quality. Therefore

design pre-compression ratio and groove of rubber O-ring seal structure in high-pressure hydrogen shall consider hydrogen swelling influence in order to avoid occurrence of high stress and O-ring extrusion.