Indentation

About: Indentation is a research topic. Over the lifetime, 13002 publications have been published within this topic receiving 340476 citations.

The Meyer hardness: A measure for plasticity?

Abstract: The physical insight into the Meyer hardness is given on the basis of the experimental results for indentation load P versus indentation depth h relations and of a simple model for elastoplastic contact deformation. The quadratic relationships of P = k 1 h 2 for loading and P = k 2 ( h − h r ) 2 for unloading with the residual depth of impression h r are essential in the elastoplastic indentation processes and mechanisms. The indentation-induced residual strain energy stored in unloaded impression is properly taken into account. The Meyer hardness is an elastic and plastic parameter that depends not only on the plasticity but also on the elasticity of material indented and significantly depends on the geometry of indenter used. The Meyer hardness is given in terms of the energy consumed to create a residual indentation impression, leading to the concepts of “work of indentation” and “ductility index.”

Indentation model and strain gradient plasticity law for glassy polymers

Abstract: Plastic deformation of metals is generally a function of the strain. Recently, both phenomenological and dislocation-based strain gradient plasticity laws were proposed after strain gradients were experimentally found to affect the plastic deformation of the metal. A strain gradient plasticity law is developed on the basis of molecular theory of yield for glassy polymers. A strain gradient plasticity modulus with temperature and molecular dependence is proposed and related to indentation hardness. The physics of the strain gradient plasticity in glassy polymer is then discussed in relation to the modulus.