Simulation of Vickers indentation of silica glass

Abstract

is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. AbstractThe indentation response of glasses can be classified under three headings: normal, anomalous and intermediate, depending on the deformation mechanism and the cracking response. Silica glass, as a typical anomalous glass, deforms primarily by densification and has a strong tendency to form cone cracks that can accompany median, radial and lateral cracks when indented with a Vickers tip. This is due to its propensity to deform elastically by resisting plastic flow. Several investigations of this anomalous behavior can be found in the literature. The present paper serves to corroborate these results numerically using the discrete element method. A new pressuredensification model is developed in this work that allows for a quantitative estimate of the densification under very high pressure. This model is applied to simulate the Vickers indentation response of silica glass under various indentation forces using the discrete element method first, and then a discrete-continuum coupling method with large simulation domains to suppress the side effects and reduce the computational time. This coupling involves the discrete element method (DEM) and the constrained natural element method (CNEM). The numerical results obtained in this work compare favorably with past experimental results.

Driving force for indentation cracking in glass: composition, pressure and temperature dependence

“…However, one must keep in mind that all information that can be deduced from this stress field is essentially qualitative for several reasons: (i) cracks as they develop strongly alter the stress field, (ii)σ was derived on the basis of the initial stressfree and pristine material situation regardless of the necessary actualization of both the geometry of the domain and the material physical properties (e.g. densification is known to significantly alter the elastic properties), and (iii) the apparent hardness as measured by means of indentation [36]; and (b) DEM-CNEM coupling numerical results [37]. Note that a 1% relative increase of the density corresponds to a pressure of about 8 GPa [38].…”

“…The depths at which densification of 1% and 20% are achieved are approximately 3 and 1.5 µm, respectively, as estimated by Raman scattering [36]. A depth of approximately 4 µm is determined by DEM [37] for 1% densification, and depths of 3 and 2 µm are estimated for 1% and 20% densification, respectively, from the analytical expression of the stress field [39].…”

Multiscale Modeling of Complex Dynamic Problems: An Overview and Recent Developments

“…Originally, this class of methods has been developed for problems of granular media in rocks mechanics [29]. More recently, it has been applied to study the damage of heterogeneous media such as concrete [49] and rocks [20], but also to study the damage of homogeneous media such as ceramics [104] and glasses [6,7,55,56]. In these studies, the material is modeled by an agglomerate of discrete elements which interact via bilateral cohesive links to ensure the cohesion of the medium.…”

A Promising Way to Model Damage in Composite and Dry Fabrics Using a Discrete Element Method (DEM)

“…After proving the ability of the method to capture kinetic damage induced by cracking phenomena in brittle materials such as silica [1], the motivation of authors is now to take advantage of the method for composite materials applications. Recent and current developments to face the challenges in composite are reported in the sections below.…”

“…The one developed by the research team in the lab consists in a direct coupling approach between a Discrete Element Method (DEM) [10] in the process zone and a more conventional continuous method, the Constrained Natural Element Method (CNEM) beyond the process zone. This coupling, based on Arlequin technique [11] has already led to very good results in static application of glass indentation [1] and more recently, in dynamic application of a laser impact on glass [12].…”