Finite element-based contact analysis of a radially functionally graded hemisphere and a rigid flat

In the present work, a normally loaded contact between a radially functionally graded hemisphere and a rigid flat is analysed in perfect slip condition for different values of gradient/inhomogeneity parameter. The analysis was performed with an axisymmetric model in commercial finite element software ANSYS 18.2. The Young's modulus, yield strength and tangent modulus (for bilinear isotropic hardening) are varied according to an exponential function. The effect of the inhomogeneity parameter on different contact behaviours, e.g., contact area, contact pressure, contact stresses, etc., of the hemisphere are obtained. Stress and deformation behaviour of the contact interface as well as of the entire hemisphere has been analysed. It is observed that for negative inhomogeneity parameter, while being deformed by the rigid flat, the summit of the hemisphere loses contact with flat and sinks in to have a concave shape at the top of the hemisphere. This phenomenon has not been reported in established literature yet.