Thermo-Mechanical Investigations of a Tribological Interface

Abstract

Numerical methods are essential to understand tribological behaviors since it is difficult to measure directly a closed contact or write representative analytical equations. In this paper, a focus on the complexity of a contact is done with the modeling of thermo-mechanical phenomena in connection with tribological triplet (mechanism, first bodies, third body). Discrete element method is chosen to have a dynamic view of a contact and is interesting to represent both damage of first bodies and cohesion of third ones. Thermo-mechanical models are described for first and third-bodies and are adjusted as a function of continuity of the body. Results regarding damage, rheology and thermal effects are studied as a consequence of cohesion of third body and applied energy by the mechanism (pressure, velocity). Because mechanical and thermal behaviors have a narrow but unclear relationship, a balance between local energy (cohesion of third body) and global energy (applied forces by mechanism) is recommended.

Effect of contact location on the crushing strength of aggregates

“…Nguyen et al (2015) proposed instead a model based on contact dynamics in which there is no elasticity in cohesive interactions, which are represented as perfectly rigid bonds with a threshold value on the tensile and shear stress above which the interaction is broken (yield criterion). Other models (Rivière et al, 2015) rely on cohesive forces at particle contacts which possess complex yielding criteria coming from the framework of cohesive zone models (Raous et al, 1999). Other approaches treat contacts and cohesive interactions by superimposing a lattice discretization to a molecular dynamics scheme (D'Addetta et al, 2002).…”

Fracture of granular materials composed of arbitrary grain shapes: A new cohesive interaction model

“…Thus, damage occurs in the sample only by breakage of cohesive interactions. More sophisticated models such as Cohesive Zone Models (CZM) which take into account the progressive damage of a cohesive contact can be found in (Raous et al, 1999;Rivière et al, 2015).…”

Role of Third Body on Bolted Joints' Self-Loosening

“…For the purpose of such local modeling, a discrete element method (DEM) [21] is used. Such approaches are the only way to model the heterogenous and discontinuous feature of the first body without using an a priori The chosen DEM to model the screw/nut threads contacts is the NSCD framework [22], widely used in the context of numerical tribology [23][24][25][26]. The main lines of this approach (time integration based on theta scheme, implicit contacts resolution via a nonlinear Gauss-Seidel algorithm) are not detailed here.…”