Modelling an abrasive wear experiment by the boundary element method

This Note presents a computational technique for simulating friction-induced wear in a tribology experiment on a plan/plan, ring-on-disc contact configuration. The boundary element method results in modest computing times and facilitates the mesh modifications used for tracking the wear profile evolution. A typical wear simulation result is presented and discussed

Tribological and corrosion wear of graphite ring against Ti6Al4V disk in artificial sea water

Severe degradations result from the friction of two antagonists in sea water environment. It is proposed to evaluate materials resistance to wear with a tribocorrosion experimental set-up which is mechanically and electrochemically instrumented. The method is illustrated with graphite and Ti6Al4V.The deposition of graphite on Ti6Al4V samples is observed and modifies the contact characteristics. Processes of graphite wear due to mechanical effect are characterised. Observations clearly indicate that Ti6Al4V degradations depend on the electrochemical potential imposed and more precisely on the electrochemical conditions in the contact zone

On a multiscale strategy and its optimization for the simulation of combined delamination and buckling

This paper investigates a computational strategy for studying the interactions between multiple through-the-width delaminations and global or local buckling in composite laminates taking into account possible contact between the delaminated surfaces. In order to achieve an accurate prediction of the quasi-static response, a very refined discretization of the structure is required, leading to the resolution of very large and highly nonlinear numerical problems. In this paper, a nonlinear finite element formulation along with a parallel iterative scheme based on a multiscale domain decomposition are used for the computation of 3D mesoscale models. Previous works by the authors already dealt with the simulation of multiscale delamination assuming small perturbations. This paper presents the formulation used to include geometric nonlinearities into this existing multiscale framework and discusses the adaptations that need to be made to the iterative process in order to ensure the rapid convergence and the scalability of the method in the presence of buckling and delamination. These various adaptations are illustrated by simulations involving large numbers of DOFs

Etude thermodynamique de l'évolution sous chargement dynamique de structures délaminées

On considère un assemblage de plaques modélisant une structure stratifiée se délaminant. La propagation du délaminage est caractérisée par la transformation d'une plaque en deux autres. On examine dans le cadre du formalisme hamiltonien l'influence d'un chargement dynamique sur une telle structure, d'un point de vue thermodynamique. L'étude du taux de restitution associé à la propagation de la fissure, considérée comme une source de chaleur localisée sur le front de délaminage, est discutée

Quasi-static evolution of delaminated structures: analysis of stability and bifurcation

Within the framework of dissipative systems with time-independent behavior, the study of the evolution of delaminated structures modeled by frames of plates is considered via a global energetic analysis. Assuming the current equilibrium state is known, the governing rate problem for the instantaneous delamination is formulated as either a system of local equations or as a global variational inequality.This global formulation enables to study stability and non-bifurcation of the evolution of a delaminated structure under quasi-static loading, corresponding to the statement of existence and uniqueness criteria for the rate solution.Two analytical applications to simple structures are presented

General relationships between microscopic and macroscopic scales for heterogeneous media with moving discontinuities.

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Mechanical transformations and discontinuities along a moving surface

Partial damage is considered in this paper. It is defined as a transformation of mechanical properties between two materials along a surface, in elasticity or plasticity. The transformation is controlled by a generalized energy criterion of the Griffith type. The equilibirum state of the structure, the total dissipation with increasing loading and the associated rate boundary value problem are studied within the frame work of standard materials. A global formulation of the rate boundary value problem allows us to charaterize the actual equilibrium state assumed to be known. Finally, the condition of stability and the possibility of bifurcation are given, as are applications to simple composite structure

Relations entre grandeurs microscopiques et macroscopiques pour un solide avec changement de phase irréversible

On étudie la caractérisation du comportement global du matériau à partir de la connaissance des propriétés locales de ses composants élastiques ou élastoplastiques. On fait l'hypothèse que l'un des matériaux constitutifs peut se transformer en un second composant, de manière irréversible, ce changement de phase n'étant dû qu'à un critère exprimé sur les grandeurs mécaniques

Relationships between macroscopic and microscopic state of variables for a solid with irreversible localized parial damage

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Stability and bifurcation with moving discontinuities: application to delamination of laminates

No abstract provide