Elastic contact to nearly incompressible coatings:: Stiffness enhancement and elastic pile-up

We have recently proposed an efficient computation method for the frictionless linear elastic axisymmetric contact of coated bodies. Here we give a brief description of the approach. We also discuss implications of the results for the instrumented indentation data analysis of coated materials. Emphasis is laid on incompressible or nearly incompressible materials ( Poisson ratio u > 0: 4): we show that the contact stiffness rises much more steeply with contact radius than for more compressible materials and significant elastic pile-up is evidenced. In addition, the dependence of the penetration upon contact radius increasingly deviates from the homogeneous reference case when the Poisson ratio increases. As a result, this algorithm may be helpful in instrumented indentation data analysis on soft and nearly incompressible layers.