Extraction of stress–strain curves of elastic–viscoplastic solids using conical/pyramidal indentation testing with application to polymers

• Published in: Mechanics of materials Vol. 40; no. 4; pp. 271 - 283
• Main Authors: Kermouche, G., Loubet, J.L., Bergheau, J.M.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier Ltd 01.04.2008; Amsterdam Elsevier Science; New York, NY
• Subjects: Cone indentation; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Inelasticity (thermoplasticity, viscoplasticity...); Mechanical contact (friction...); Physics; Polymeric materials; Representative strain rate; Solid mechanics; Structural and continuum mechanics; Time-dependent behaviour; Cone indentation; Polymeric materials; Representative strain rate; Time-dependent behaviour; Viscoelastic fluid; Hardness test; Cone; Stress strain relation; Nanoindentation; Methyl methacrylate polymer; Mechanical contact; Elastoviscoplasticity; Indentation; Microhardness; Nanometer scale; Plastic coating; Inelasticity; Bingham plastic; Elastoplasticity; Glassy polymer; Strain rate
• ISSN: 0167-6636; 1872-7743
• DOI: 10.1016/j.mechmat.2007.08.003

The increasing use of polymeric materials as thin coatings requires appropriate mechanical characterization methods at micro and nano-scale taking account of time-dependent effects. In this paper, a nanoindentation method developed initially for elastoplastic solids is extended to elasto-viscoplastic solids. It allows to determine very easily and quickly a first approximation of the stress–strain curves of Bingham–Norton elastic–viscoplastic materials. The procedure is based on the use of different indenter geometries and different loading conditions. The method is then extended to the mechanical characterization of glassy polymers in assuming a G’sell law for describing their behaviour in compression. In the last part, we apply this method to nanoindentation tests on PMMA, PS and PC samples.