Spherical Indentation in Elastoplastic Materials: Modeling and Simulation
Abstract
An implicit axisymmetric finite element model is implemented to study the response of an elastoplastic substrate in contact with a rigid spherical indenter. A finite strain, rate-independent, isotropic elastic-plastic constitutive formulation is invoked for the behavior of the substrate. Relative influences on the load displacement response of elastic stiffness constants and plastic properties of the substrate are investigated via a series of simulations. With increasing depth of indentation, the flow stress overtakes the elastic modulus as the dominant mechanical property with regard to the extracted mechanical response. In agreement with theoretical predictions, Poisson's ratio exerts a very minor effect on the load displacement curves, with this effect further diminishing upon yielding of the substrate at greater depths of indentation. Numerical results are compared with experimental load displacement data for pure metals, alloys, and composite microstructures comprised of titanium, tungsten, tin, and/or polymeric nylon. Relatively close agreement between experiment and simulation is achieved over the loading phase of the indentation cycle for exclusively metallic substrates. Comparatively less success is attained in matching numerical and experimental results for materials of polymeric composition, presumably because of the effects of anisotropy, stain rate dependence (e.g. viscosity) and/or heterogeneities at the microstructural level not captured by the constitutive theory used in the simulations.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 2005
- Accession Number
- ADA433794
Entities
People
- John D. Clayton
Organizations
- United States Army Research Laboratory