Adjusting contact surface normals at symmetry planes

For small-sliding contact the tests verify that the surface normals are properly adjusted such that a secondary node finds an intersection with a curved main surface at the symmetry plane (see Figure 1). It also verifies that the proper clearance is calculated at the symmetry plane.

For finite-sliding contact the tests verify that the surface normals are properly adjusted and that the end segments of a two-dimensional contact surface are properly smoothed at the symmetry plane.

Some input files use a local nodal coordinate system to ensure that the surface normals are properly adjusted for the local system.

The models consist of two concentric deformable cylinders. A quarter-symmetry model is used. The initial clearance between both cylinders is 0.1. The loading consists of two steps. In the first step a pressure of 100 is applied on the outer cylinder such that the surface comes into contact with the inner cylinder. In the second step the pressure is released such that the elastic model returns to its original state.