Real contact area and friction property of rubber with two-dimensional regular wavy surface

The elastic contact of two-dimensional regular wavy surface with a flat surface and its frictional behaviour are studied by using three types of blocks of silicone rubber as specimen. The friction force as well as the real contact area is markedly affected by the shape of the valley of the wavy surface. In the case of the specimens with U-shaped trough, each contact spot touches the neighbours before complete contact, resulting in the extinction of the percolation channels allowing the fluid flow. If the tests were conducted in wet environment, the rate of increase in the real contact area with the load shows sharp drops when each contact spot touches the neighbours, which inhibits the increase in the friction force.