The mechanical response of amorphous silica (or silica glass) under hydrostatic compression for very high pressures up to 25 GPa is modelled via an elastic-plastic constitutive equation (continuum mechanics framework). The material parameters appearing in the theory have been estimated from the ex situ experimental data from Rouxel et al. [Rouxel T, Ji H, Guin JP, Augereau F, Rufflé B J Appl Phys 2010;107(9):094903]. The model is shown to capture the major features of the pressure-volume changes response from the in situ experimental work of Sato and Funamori [Sato T, Funamori N Phys Rev Lett 2008;101:255502]. In particular, the onset and saturation of densification, the increase in elasticity parameters (bulk, shear and Young's moduli) andPoisson's ratio are found to be key parameters of the model.

Abstract. Silica glass is known to exhibit permanent changes in density under very high pressures. These changes may reach 21%. The sharp indentation test develops pressures underneath the indenter that trigger densification. Recently, we have proposed a constitutive modeling of the pressure-induced process accounting for its salient features: densification threshold, hardening, saturation of densification and permanent increase in elastic moduli. We examine in this paper the possibility that densification could be the only mechanism for creating an imprint by indentation. We consider different models with growing complexity that we implement in a finite element software. Results indicate that the combination of shear and pressure as a driving force to densification may account for the mechanical response of the indentation test as well as the presence of densified zone underneath the imprint.

No abstract

No abstract