Numerical simulation of the frictional heat problem of subway brake discs considering variable friction coefficient and slope track

2021 ◽  
pp. 105794
Author(s):  
Yuqi Yang ◽  
Bing Wu ◽  
Quan Shen ◽  
Guangwen Xiao
Keyword(s):  
Numerical Simulation ◽  
Friction Coefficient ◽  
Frictional Heat ◽  
Heat Problem ◽  
Brake Discs ◽  
Variable Friction ◽  
Frictional Heat Problem

Effect of variable friction coefficient on sheet metal drawing

2002 ◽  
Vol 35 (2) ◽  
pp. 97-104 ◽  
Author(s):  
Haluk Darendeliler ◽  
Metin Akkök ◽  
Can Ali Yücesoy
Keyword(s):  
Friction Coefficient ◽  
Sheet Metal ◽  
Variable Friction

scholarly journals AN INVESTIGATION ON THE EFFECTS OF MICRO-PARAMETERS ON THE STRENGTH PROPERTIES OF ROCK

2021 ◽  
Vol 36 (1) ◽  
pp. 111-119
Author(s):  
Behzad Jafari Mohammadabadi ◽  
Kourosh Shahriar ◽  
Hossein Jalalifar ◽  
Kaveh Ahangari
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Friction Coefficient ◽  
Critical Stress ◽  
Friction Angle ◽  
Strength Properties ◽  
Brazilian Tensile Strength ◽  
The Relationship

Rocks are formed from particles and the interaction between those particles controls the behaviour of a rock’s mechanical properties. Since it is very important to conduct extensive studies about the relationship between the micro-parameters and macro-parameters of rock, this paper investigates the effects of some micro-parameters on strength properties and the behaviour of cracks in rock. This is carried out by using numerical simulation of an extensive series of Uniaxial Compressive Strength (UCS) and Brazilian Tensile Strength (BTS) tests. The micro-parameters included the particles’ contact modulus, the contact stiff ness ratio, bond cohesion, bond tensile strength, the friction coefficient and the friction angle, and the mechanical properties of chromite rock have been considered as base values of the investigation. Based on the obtained results, it was found that the most important micro-parameters on the behaviour of rock in the compressive state are bond cohesion, bond tensile strength, and the friction coefficient. Also, the bond tensile strength showed the largest effect under tensile conditions. The micro-parameter of bond tensile strength increased the rock tensile strength (up to 5 times), minimized destructive cracks and increased the corresponding strain (almost 2.5 times) during critical stress.

Simulation Study of Granular Compaction Dynamics under Vertical Tapping

2007 ◽  
Vol 555 ◽  
pp. 107-112 ◽  
Author(s):  
D. Arsenović ◽  
S.B. Vrhovac ◽  
Z.M. Jakšić ◽  
Lj. Budinski-Petković ◽  
A. Belić
Keyword(s):  
Numerical Simulation ◽  
Molecular Dynamics ◽  
Friction Coefficient ◽  
Simulation Study ◽  
Material Properties ◽  
Two Dimensions ◽  
Second Phase ◽  
Hard Disks ◽  
Compaction Process ◽  
Granular Compaction

We study by numerical simulation the compaction dynamics of frictional hard disks in two dimensions, subjected to vertical shaking. Shaking is modeled by a series of vertical expansions of the disk packing, followed by dynamical recompression of the assembly under the action of gravity. The second phase of the shake cycle is based on an efficient event−driven molecular−dynamics algorithm. We analyze the compaction dynamics for various values of friction coefficient and coefficient of normal restitution. We find that the time evolution of the density is described by ρ(t)=ρ∞ − ρEα[−(t/τ)α], where Eα denotes the Mittag−Leffler function of order 0<α<1. The parameter τ is found to decay with tapping intensity Γ according to a power law τ ∝ Γ−γ , where parameter γ is almost independent of the material properties of grains. Also, an expression for the grain mobility during compaction process has been obtained.

Thermo-mechanical modelling of the Friction Stir Spot Welding process: Effect of the friction models on the heat generation mechanisms

2022 ◽  
pp. 146442072110709
Author(s):  
Nasra Hannachi ◽  
Ali Khalfallah ◽  
Carlos Leitão ◽  
Dulce Rodrigues
Keyword(s):  
Numerical Simulation ◽  
Heat Generation ◽  
Spot Welding ◽  
Welding Process ◽  
Friction Stir Spot Welding ◽  
Frictional Heat ◽  
Contact Conditions ◽  
Friction Stir ◽  
Friction Models ◽  
Generation Mechanisms

Friction Stir Spot Welding involves complex physical phenomena, which are very difficult to probe experimentally. In this regard, the numerical simulation may play a key role to gain insight into this complex thermo-mechanical process. It is often used to mimic specific experimental conditions to forecast outputs that may be substantial to analyse and elucidate the mechanisms behind the Friction Stir Spot Welding process. This welding technique uses frictional heat generated by a rotating tool to join materials. The heat generation mechanisms are governed by a combination of sliding and sticking contact conditions. In the numerical simulation, these contact conditions are thoroughly dependent on the used friction model. Hence, a successful prediction of the process relies on the appropriate selection of the contact model and parameters. This work aims to identify the pros and cons of different friction models in modelling combined sliding-sticking conditions. A three-dimensional coupled thermo-mechanical FE model, based on a Coupled Eulerian-Lagrangian formulation, was developed. Different friction models are adopted to simulate the Friction Stir Spot Welding of the AA6082-T6 aluminium alloy. For these friction models, the temperature evolution, the heat generation, and the plastic deformation were analysed and compared with experimental results. It was realized that numerical analysis of Friction Stir Spot Welding can be effective and reliable as long as the interfacial friction characteristics are properly modelled. This approach may be used to guide the contact modelling strategy for the simulation of the Friction Stir Spot Welding process and its derivatives.

scholarly journals Low-Cyclic Loading Tests of Self-Centering Variable Friction (SCVF) Brace

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Qingguang He ◽  
Yanxia Bai ◽  
Weike Wu ◽  
Yongfeng Du
Keyword(s):  
Finite Element ◽  
Friction Coefficient ◽  
Energy Dissipation ◽  
Cyclic Loading ◽  
Variable Friction ◽  
Loading Tests ◽  
Low Cyclic Loading ◽  
Energy Dissipation System ◽  
Cyclic Loading Tests ◽  
Dissipation System

A novel assembled self-centering variable friction (SCVF) brace is proposed which is composed of an energy dissipation system, a self-centering system, and a set of force transmission devices. The hysteretic characteristics and energy dissipation of the SCVF brace with various parameters from low-cyclic loading tests are presented. A finite element model was constructed and tested under simulated examination for comparative analysis. The results indicate that the brace shows an atypical flag-type hysteresis curve. The SCVF brace showed its stable self-centering ability and dissipation energy capacity within the permitted axial deformation under different spring and friction plates. A larger deflection of the friction plate will make the variable friction of this SCVF brace more obvious. A higher friction coefficient will make the energy dissipation capacity of the SCVF brace stronger, but the actual friction coefficient will be lower than the design value after repeated cycles. The results of the fatigue tests showed that the energy dissipation system formed by the ceramic fiber friction blocks and the friction steel plates in the SCVF brace has a certain stability. The finite element simulation results are essentially consistent with the obtained test results, which is conducive to the use of finite element software for calculation and structural analysis in actual engineering design.

The Numerical Simulation Research of Thermal Mechanical Simulation Compression Behavior with Uneven Temperature on End

2013 ◽  
Vol 762 ◽  
pp. 368-373
Author(s):  
Lei Yao ◽  
Zheng Fang ◽  
Zhang Ge
Keyword(s):  
Numerical Simulation ◽  
Temperature Field ◽  
Friction Coefficient ◽  
Strain Rate ◽  
Deformation Resistance ◽  
Simulation Research ◽  
Compression Behavior ◽  
Mechanical Simulation ◽  
Strain And Strain Rate ◽  
Lubrication Condition

The study has been performed concerning the influence of temperature field created by heat conduction between sample and the anvils, and the influence of lubrication condition (friction coefficient) on thermal mechanical compression test with numerical simulation, with regard to deformation resistance and distributions of strain and strain rate. The results show that temperature field has an effect on deformation resistance and distributions of strain and strain rate. That will influence on the results from thermal mechanical simulation tests. Further, the results also show that friction coefficient has no influence on deformation resistance, but the friction coefficient will result in uneven distribution of strain and strain rate.

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