Microstructural effects in multilayers with large moduli contrast loaded by flat punch

An efficient solution methodology is employed for the frictionless contact of half-planes built up with large number of layers to study the effect of microstructural refinement on the surface and subsurface stress fields. Half-planes with increasing numbers of alternating stiff and soft layer pairs spanning a fixed depth below the top surface are considered to determine the convergence behavior of the contact pressure and subsurface stressess relative to the corresponding quantities in fully or partially homogenized configurations with macroscopically equivalent properties. The results indicate that not all stress components converge to the corresponding values in the fully homogenized configuration with increasing microstructural refinement. This is only achieved by a partial homogenization wherein the layered half-plane is homogenized below a certain depth with the top surface layers retained. The number of retained surface layers required for an accurate stress field reproduction depends on the punch length and microstructural scale and depth of the alternating layers. The characteristic contact pressure profiles observed in the layered configurations suggest a basis for the development of a sensing technique for the microstructural architecture and property identification of the subsurface region.