On modeling the micro-indentation response of an amorphous polymer

By L. Anand, Nicoli M. Ames. 2006

229 citations recorded by the source corpus.

Abstract Interest in instrumented indentation experiments as a means to estimate mechanical properties has grown rapidly in recent years. Although numerous nano/micro-indentation experimental studies on polymeric materials have been reported in the literature, a corresponding methodology for extracting material property information from the experimental data does not exist. This situation for polymeric materials exists primarily because baseline numerical analyses of sharp indentation using appropriate large deformation constitutive models for the nonlinear viscoelastic–plastic response of these materials appear not to have been previously reported in the literature. An existing, widely used theory for amorphous polymers (e.g. [Boyce, M., Parks, D., Argon, A.S., 1988. Large inelastic deformation of glassy polymers. Part 1: Rate dependent constitutive model. Mechanics of Materials 7, 15–33; Arruda, E.M., Boyce, M.C., 1993. Evolution of plastic anisotropy in amorphous polymers during finite straining. International Journal of Plasticity 9, 697–720]) has been recently found to lack sufficient richness to enable one to quantitatively reproduce the major features of the indentation load-versus-depth curves for some common amorphous polymers [Gearing, B.P., 2002. Constitutive equations and failure criteria for amorphous polymeric solids. Ph.D. thesis, Massachusetts Institute of Technology]. This study develops a new continuum model for the viscoelastic–plastic deformation of amorphous polymeric solids. We have applied the constitutive model to capture salient features of the mechanical response of the amorphous polymeric solid poly(methyl methacrylate) (PMMA) at ambient temperature and stress states under which this material does not exhibit crazing. We have conducted compression-tension strain-controlled experiments, as well as stress-controlled compression-creep experiments, and these experiments are used to calibrate the material parameters in the constitutive model for PMMA. We have implemented our constitutive model in a finite-element computer program, and using this finite-element program we have simulated micro-indentation experiments on PMMA. We show that our constitutive model and finite element simulations reproduce the experimentally-measured indentation load-versus-depth response with reasonable accuracy.

Subfields: Atomic and Molecular Physics, and Optics, Mechanical Engineering, Mechanics of Materials

View Paper: https://www.semanticscholar.org/paper/120b67456dde00b56c690673cd188e8bc72938e0

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Atomic and Molecular Physics, and Optics

In Mechanical Engineering

In Mechanics of Materials

Citations in the corpus

A thermo-mechanically-coupled large-deformation theory for amorphous polymers in a temperature range which spans their glass transition (2010, background): “…by Lallit Anand as his Khan International Medal lecture at the Plasticity 2007 conference in Alaska. to represent the large deformation elastic-viscoplastic behavior of these materials (e.g., Parks et al., 1985; Boyce et al., 1988; Govaert et al, 2000; Anand and Gurtin, 2003; Anand and Ames, 2006).”
High Strain Rate Mechanics of Polymers: A Review (2016, background): “accounts for the strain hardening post-yield due to the alignment of the macromolecular network built of entangled polymer molecules [26].”
Historical review of internal state variable theory for inelasticity (2010, methodology): “Based on the thermodynamics of Anand and Gurtin (2003), Gearing and Anand (2004) used ISVs to represent crazing and damage for polymers and later Anand and Ames (2006) added ISVs to represent other mechanisms as inelastic dissipative mechanisms for viscoelastic polymers.”
Thermally actuated shape-memory polymers: Experiments, theory, and numerical simulations (2010, background): “Over the past thirty years, considerable effort has been devoted to developing constitutive models to represent the large-deformation elastic-viscoplastic behavior of amorphous thermoplastic polymers (cf., e.g., Parks et al., 1985; Boyce et al., 1988; Buckley and Jones, 1995; Boyce et al., 2000; Gov”