Boundary element numerical modelling as a surface engineering tool: application to very thin coatings

The boundary element approach in plane strain elastic contact is extended t o bilayer composites with very low generalised coating thickness t(c)* = t (c)/a(H) (a(H) = Hertzian contact radius; t((c)) = coating thickness). Coat ings more compliant than their substrates (E-(c)/E-(s) = 0.41) and the inve rse (E-(c)/E-(s) = 2.44) are studied together with the influence of frictio n (mu = 0, 0.1, 0.4). The major features evidenced by these numerical simul ations are the important stress discontinuities at the coating/substrate in terface in all cases and a specific, low thickness effect leading to a stre ss minimum in the high modulus coatings instead of the stress maximum expec ted from the FEM literature and from our own results for 'thick' coatings. (C) 1999 Elsevier Science S.A. All rights reserved.