Fig. 5.
Normal contact of saddle-shaped layers. The layers are identical but rotated by 90 degrees about the axis passing through the center of, and normal to, the contact surfaces (the y – axis). The contact surfaces were generated from the inner rim of the surface of a torus; their principal radii of curvature at the center point are -3.5 mm and +2.5 mm; their rim projects onto the x – z plane as a circle with a diameter of 3 mm. Each layer has a thickness of 0.4 mm and is supported on a rigid substrate; the bottom layer's substrate is stationary and the top layer's substrate has a prescribed ramp displacement uy at a ramp rate of -0.3 mm/s, with a final value of -0.3 mm. The model has a total of 21420 nodes and 18784 elements. Each layer's mesh has a dual bias along the layer thickness (20 elements). The mesh is shown at three select time points.