Simulation of Energy Dissipation and Heat Transfers of a Braking System Using the Discrete Element Method: Role of Roughness and Granular Plateaus

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Viet-Dung Nguyen ◽  
Philippe Dufrénoy ◽  
Patrice Coorevits
Keyword(s):  
Energy Dissipation ◽  
Discrete Element Method ◽  
Discrete Element ◽  
Heat Propagation ◽  
Point Of View ◽  
Disk Interface ◽  
Braking System ◽  
Interparticle Friction ◽  
Heat Transfers ◽  
Element Method

Abstract The objective of this study focuses on the energy dissipation by friction on the interface of a braking system and the effects of roughness and granular plateaus on heat propagation. Faced with the difficulty of defining velocity accommodation and thermal partition between the two bodies in contact (disk and pad, for example,), the authors model the third body (friction) layer with circular particles detached from the pad. From a numerical point of view, this paper proposes a strategy of storing mechanical calculations in steady-state and using it for successive thermal processing in discrete element method (DEM) code. Thus, the heat is generated due to interparticle friction and is dissipated in the disk/pad interface by conductance. Accordingly, this coupling micro–macro model aims to determine the temperature rise of the pad/disk interface and to identify the equivalent thermal resistance. In line with that, the authors provide discussions of these parameters compared to experimental/empirical data as reported in the literature review and limitations of the model.

scholarly journals ВПЛИВ КОНСТРУКЦІЙ ВІДЦЕНТРОВИХ ЗМІШУВАЧІВ НА ЇХ ЗГЛАДЖУВАЛЬНУ ЗДАТНІСТЬ

2020 ◽  
Vol 142 (1) ◽  
pp. 11-18
Author(s):  
В. В. Стаценко ◽  
О. П. Бурмістенков ◽  
Т. Я. Біла
Keyword(s):  
Discrete Element Method ◽  
Residence Time ◽  
Mixing Time ◽  
Discrete Element ◽  
Point Of View ◽  
Design Parameters ◽  
Discrete Elements ◽  
Bulk Materials ◽  
Design Features ◽  
Element Method

Studying the influence of continuous centrifugal mixers design features on their smoothing ability. The methods used are discrete elements, mathematical modeling and regression analysis. The paper considers five continuous centrifugal mixers designs with conical and parabolic rotors. The mixers design features are determined, allowing to change their smoothing ability. Mathematical models of the bulk materials particles movement inside each mixer have been developed based on the discrete element method. The considered mixers reaction to a step change of the key component amount is investigated. The transients parameters are calculated and the particles average residence time in the mixer is determined. It is established that the introduction of turbulizers in the mixers design increases the particles kinetic energy, which leads to a decrease in their residence time in the mixer. Moreover, the absence of a turbulizer leads to a decrease in the mixing intensity. It was also found that the most effective way to increase the mixer smoothing ability is the introduction of additional rotors. In terms of the technological and design parameters combination, the use of mixers with a conical rotor and a turbulizer is the most effective from the point of view for increasing the smoothing ability. On the discrete element method basis, the bulk materials particles movement models in continuous centrifugal mixers of five designs have been developed. The influence of the mixers design features on their smoothing ability and average mixing time is determined. The results obtained allow us to select the appropriate mixer design according to the specified requirements for smoothing ability.

Numerical Simulation of Granite Sawing by Discrete Element Method

2009 ◽  
Vol 16-19 ◽  
pp. 1283-1288
Author(s):  
Yong Ye ◽  
Yuan Li ◽  
Xi Peng Xu
Keyword(s):  
Discrete Element Method ◽  
Discrete Element ◽  
Point Of View ◽  
Bending Tests ◽  
Three Point Bending ◽  
Deformation Stage ◽  
Initiation And Propagation ◽  
Discontinuous Deformation ◽  
Sawing Process ◽  
Element Method

Granite is a kind of typical discrete material, which experiences from continuous deformation stage, discontinuous deformation stage to fracture stage under sawing forces. Using discrete element method (DEM) to study the process of sawing granite will help us to understand the removal mechanism of granite from the microscopic point of view. In this paper, numerical uniaxial compression and three-point bending tests were conducted to determine the microscopic parameters of the granite specimen firstly, and then simulation was performed for sawing of the specimen. The sawing process, deformation characteristics of granite and the effect of initiation and propagation of cracks on fracture process of granite were investigated. The emphasis was laid on analyzing the variation of sawing forces under different sawing parameters. The simulation results agree well with that of experiments, indicating that DEM can reflect the external macroscopic change of granite by changing the internal microscopic structure. The conclusions in this study would be useful to the modeling of sawing processes and engineering applications.

Discrete element method (DEM) numerical modeling of double-twisted hexagonal mesh

2008 ◽  
Vol 45 (8) ◽  
pp. 1104-1117 ◽  
Author(s):  
David Bertrand ◽  
François Nicot ◽  
Philippe Gotteland ◽  
Stéphane Lambert
Keyword(s):  
Discrete Element Method ◽  
Experimental Tests ◽  
Discrete Element ◽  
Numerical Approach ◽  
Point Of View ◽  
Wire Mesh ◽  
Model Parameters ◽  
Elastoplastic Behavior ◽  
Mesh Model ◽  
Element Method

Double-twisted hexagonal mesh is used in several fields of civil engineering (gabion structures, retaining nets against rockfalls, etc.). This paper presents an approach based on the discrete element method (DEM) to model this specific mechanical system. Constitutive modeling in finite strains is proposed to take into account the elastoplastic behavior with hardening of the metallic wire mesh. Model parameters are calibrated from a macroscopic point of view by comparing simulations to experimental tensile strength tests performed at the wire-mesh sheet scale. Additional experimental tests, with different mesh sizes and wire diameters, are conducted, yielding valuable data to validate this numerical approach. Lastly, the modeling capabilities are investigated. The simulation of a rockfall-protection structure subjected to an impact loading is presented and the results are discussed from an engineering point of view.

Discrete element method to model cracking for two layer systems

TAPPI Journal ◽  
2019 ◽  
Vol 18 (2) ◽  
pp. 101-108
Author(s):  
Daniel Varney ◽  
Douglas Bousfield
Keyword(s):  
Discrete Element Method ◽  
Flexural Modulus ◽  
Single Layer ◽  
Discrete Element ◽  
Flexural Stress ◽  
Layer System ◽  
Three Point Bending ◽  
Moving Force ◽  
Coating Layers ◽  
Element Method

Cracking at the fold is a serious issue for many grades of coated paper and coated board. Some recent work has suggested methods to minimize this problem by using two or more coating layers of different properties. A discrete element method (DEM) has been used to model deformation events for single layer coating systems such as in-plain and out-of-plain tension, three-point bending, and a novel moving force picking simulation, but nothing has been reported related to multiple coating layers. In this paper, a DEM model has been expanded to predict the three-point bending response of a two-layer system. The main factors evaluated include the use of different binder systems in each layer and the ratio of the bottom and top layer weights. As in the past, the properties of the binder and the binder concentration are input parameters. The model can predict crack formation that is a function of these two sets of factors. In addition, the model can predict the flexural modulus, the maximum flexural stress, and the strain-at-failure. The predictions are qualitatively compared with experimental results reported in the literature.

Sign in / Sign up

Export Citation Format

Share Document