Geometry and model
The rubber gasket is modeled as a quarter of a plane strain section, initially in contact with a flat rigid surface. The clearance between the plastic backbone and the surface is 0.612 mm (.024 in). The height of the bead in the gasket is 1.097 mm (.043 in). The backbone is modeled with a linear elastic material with a Young's modulus of 8000.0 MPa (1160 ksi) and a Poisson's ratio of 0.4. In Abaqus/Standard the gasket is modeled as a fully incompressible hyperelastic material, which is much softer than the backbone material at all strain levels. In Abaqus/Explicit a small amount of compressibility is assumed for the gasket material. The nonlinear elastic behavior of the gasket is described by a strain energy function that is a first-order polynomial in the strain invariants. The model is discretized with first-order quadrilaterals. Standard elements are used for the backbone. In Abaqus/Standard full-integration hybrid elements are used for the gasket, while reduced-integration elements are used to model the gasket in Abaqus/Explicit. The interface between the gasket and the backbone is assumed to be glued with no special treatment required. A single surface definition covers all of the free surface of the gasket and the backbone. Through the definition of contact pairs, this surface is allowed to contact both the rigid surface and itself. A small amount of friction (Coulomb coefficient of 0.05) is applied to the interface with the rigid surface, which is assumed to be lubricated. Sticking surface behavior, through the specification of rough friction (Frictional Behavior), is applied when the gasket contacts itself, denoting a clean surface.