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

TL;DR

This paper introduces an efficient computational method for analyzing elastic contact in nearly incompressible coatings, revealing significant stiffness increases and pile-up effects relevant for indentation data interpretation.

Contribution

The paper presents a new computational approach specifically tailored for nearly incompressible materials, improving understanding of contact mechanics in coated layers.

Findings

Contact stiffness increases steeply with radius for nearly incompressible materials.

Significant elastic pile-up observed in nearly incompressible coatings.

Penetration-contact radius relationship deviates from homogeneous case with higher Poisson ratio.

Abstract

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.