  We have recently proposed an efficient computation method for the
frictionless linear elastic axisymmetric contact of coated bodies [A. Perriot
and E. Barthel, J. Mat. Res. 19 (2004) 600]. 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 $\nu>0.4$): 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.
