Analysis of Elastomeric O-Ring Seals in Compression Using the Finite Element Method

The need for a methodology to determine the stiffness characteristics of elastomeric seals with complex geometry has prompted an investigation using a commercially available finite element code. Axial and radial compression of O-rings, as well as the influence of restraining grooves and friction, are investigated. Axisymmetric analyses are performed, and their results are compared with those obtained by other researchers who assumed plane strain conditions. The differences in the results of the axisymmetric and plane strain loading conditions increase with the level of compression, except for one loading case. The method of reduced integration is shown to effectively handle the problem of high localized hydrostatic stresses, which are especially enhanced in confined geometries, and to provide accurate results. Stiffness characteristics of O-ring seals having a range of geometric and material properties are given in a nondimensional form. This form allows for general modeling of the O-ring stiffness as a force and a spring at compression (i.e., deformation) levels up to 32 percent.