Electromechanical prediction of the regime of lubrication in ball bearings using Discrete Element Method

Digital twin by DEM for ball bearing operating under EHD conditions

“…The factor N A β 3M can be deduced by considering permittivity and density at atmospheric pressure. According to the formula established by Dowson and Higginson [33], the variation of the lubricant density as a function of the contact pressure is given by following equation ( 11): ρ = ρ 0 0.59 • 10 9 + 1.34 • P Hertz 0.59 • 10 9 + P Hertz (11) with ρ 0 the ambient-pressure density and P Hertz the Hertz contact pressure. In Figure 6a are plotted the dielectric constant evolution of synthetic oil film (Tab.…”

“…The electrical capacitance, on the other hand, is specifically linked to the contact interface thickness that accommodates the lubricant film. In the field of ball bearing diagnosis, the electrical techniques have been used to measure the load distribution by capacitance sensors [10] as well as to highlight the angular speed effect on the lubrication regime by means of the electrical resistance [11]. More recently, Jablonka et al [12] proposed a quantitative evaluation of lubricant film thickness in a radially loaded deep-groove ball bearing using electrical capacitance measurements.…”

“…Unlike FEM, the multibody method offers the advantage of allowing a description taking into account the entire bearing, often with the exception of the cage, for modeling the loading distribution and lubrication effects [14,15]. Recently DEM has been used successfully for simulating the dynamic behavior of bearings with tribology enrichments [16] as well as for modeling lubrication regimes by means of an EHD model [11,17]. To achieve this, the digital twin of ball bearings implements a major part of the functionalities according to the state of the art, such as the slice model, the mutual influences of neighboring elements with clearance, elliptical Hertzian contact model, lubricant film estimation, damping forces, centrifugal forces, etc.…”

Numerical investigation of heat conduction in heterogeneous media with a discrete element method approach

“…Indeed, this latter naturally accounts for discontinuities and is all well-suited to deal with a large spectrum of multi-scale and multiphysical phenomena. This approach originally developed by Cundall [35] to treat issues in rock mechanics field has been later applied to numerous problems, from the silo discharge [36] to the tribology of the wheel-rail contact [37] through the defect diagnosis in ball bearings [38,39] and the simulation of crack propagation in continuous media [40,41,42]. Besides, a DEM based model was also investigated to simulate heat transfer by conduction in particulate systems using a contact conductance model introduced at the scale of the elementary inter-particular bond [31,43,44].…”

Halo approach to evaluate the stress distribution in 3D discrete element method simulation: validation and application to flax/bio based epoxy composite

“…Indeed, the DEM enables a good description of granular materials, using discrete rigid elements interacting with their neighbors under contact or cohesive laws. This method was later used in many other fields such as geotechnical applications [2], agriculture [3] and tribology [4,5]. DEM was also developed to model continuous media and simulate solid materials like concrete [6], as well as cracking process, especially in brittle materials such as ceramic [7].…”