Science topic

# Friction - Science topic

Surface resistance to the relative motion of one body against the rubbing, sliding, rolling, or flowing of another with which it is in contact.

Publications related to Friction (10,000)

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‘Perpetual motion’ is a hypothetical type of motion which continues forever without any external energy input contributing to this system. Students should know that this is generally impossible because of energy losses due to friction or other non-conservative forces, or because some assumption has been made which violates the first or second law o...

To study the effect of wheel polygonal wear (WPW) on temperature and vibration behaviours of a high-speed train braking system, a rigid-flexible coupled vehicle system dynamics model and a thermo-mechanical coupled finite element (FE) model of a braking system are developed in this study. The accuracy of the vehicle dynamics model and FE model are...

This work investigated the dynamic responses and evaluated the performance of a two-degree-of-freedom (2DOF) coupled coil-magnet electromagnetic vibration harvester excited at low frequencies. Three different connection modes with individual, in-series, and in-parallel configurations of the transduction coils were considered. Such approach was take...

Nowadays, optimizing the movement of automatic subsurfaces is very important in marine industries due to increasing speed, increasing functional range and reducing energy consumption. In the upcoming research, with a comprehensive numerical study, using two software, Ansys Fluent and StarCCM, to investigate the effect of different methods of reduci...

In this paper, stochastic planar stick–slip motions are investigated using a slider-on-belt model where the coefficient of friction (COF) of the contact interface is modelled as a random field. New three-variable stick–slip transition criteria are proposed to improve the accuracy and robustness of the algorithm. Stochastic analyses are performed co...

The article presents the results of a study of wire drawing in a monolithic die. In the simulator of metal forming processes QForm, which is based on the finite element method, studies were carried out on drawing wire from steel grade 10 (1.1121) ∅3.0 mm from a billet ∅3.5 mm in the absence of friction at the contact of a monolithic die-billet. Dur...

This is a follow-up on three recent studies of the significance of impact-parameter-dependent electronic energy loss in the stopping of low-energy ions in matter (Sigmund and Schinner, 2017; Shulga et al., 2020; Schinner et al., 2021). With reference to the friction model of electronic stopping we distinguish between two deviations from velocity-pr...

This study is a contribution to the knowledge of rocks mechanical properties in Yaounde, with a scope on failure parameters. In most instances, this goal is achieved by carrying out XP P94-424 standard shear tests. Thus, the tests were carried out on two joint samples, using the experimental device of the Fondasol laboratory (France). However, the...

This paper proposes a new concise mathematical model of gear transmission dynamics with asymmetric load-dependent friction. It is built only upon the rigid-contact mechanics and the Coulomb friction law, but provides a new theoretical perspective on dynamic and static characteristics of gear transmissions. The presented model is of the form of a di...

This paper reported an experimental and numerical study of a novel brace-type hybrid damper composed of steel slit plates enhanced by the friction mechanism. A test programme including six proof-of-concept specimens was carried out. The test results showed that the specimens exhibited multiple yielding stages, and the hysteretic response curves of...

This study comprehensively studied the bolt bearing behavior on the influence of friction based self-centering prestressed concrete (SCPC) frames. Based on the mechanism and test results of a SCPC connection with variable friction dampers (VFD), the theoretical analyses for the VFD-SCPC connection considering the whole procedure of friction bolts r...

In the construction of pipe jacking, due to the effect of jacking force, slurry pressure, axis deviation, stoppage and geological conditions, the mechanical behaviors of pipe are very complex. Additionally, most of the calculation models of pressure around the pipes in the existing standards only consider water and earth pressure, which is differen...

The computational prediction of the failure processes of concrete under compression is still a challenge. Several researchers have proposed mesoscale models to have a better understanding of the influence of the distinct phases of the concrete on the fracture process. In this sense, this work proposes an extension of the mesoscale model proposed by...

In this work, we have mathematically modeled a 1DOF parametric oscillator with stiffness-hardening characteristics and dry friction and investigated both experimentally and numerically the bifurcation dynamics. The system consists of a cart moving along a linear rolling guide widely used in the industry. It has a stiffness comprised of two componen...

Aerodynamic performance of SD7062 airfoil in two-dimensional unsteady flows at high Reynolds number (≈ 5 × 10^6) has been investigated numerically for a wide range of angles of attack. The k-ω SST turbulence model is used to predict turbulent flow behavior. Time-averaged aerodynamic coefficients of unsteady simulations are compared with the steady...

This paper analyses the impact of matching frictions in the Portuguese labour market on individual unemployment hazard rates and unemployment durations. The coexistence of permanent contracts and temporary contracts in the Portuguese (dual) labour-market is akin to a matching friction, with a contract-type mismatch between jobseekers who prefer per...

The impact of diffusion thermo on transient natural convection flow of a chemically reactive fluid with heat source/sink in a tube is investigated. The Laplace transform technique enables the governing equations to be solved analytically with the solutions inverted by the Riemann-sum approximation method. Constant values of Prandtl number and Schmi...

Cylindrical roller bearing is an important component of the airflow root blower of a power generation plant, and its malfunction has been identified as one of the root causes of poor quality demineralized water produced during operation. Hence, there is need to study the dynamic behaviour of a typical cylindrical roller bearing of an airflow root b...

The objective of the study was to determine the geometric, gravimetric, aerodynamic, and frictional properties of maize grain as affected by varietal differences and moisture content. Honampa, Omankwa, Abontem, Timtim, and Obatanpa were the five maize grain varieties studied. Moisture content, geometric properties, gravimetric properties, aerodynam...

Severe floor heave in underground soft rock roadways heavily affects mine safety and production efficiency. In the present study, the context of the Shanghaimiao mining area is analyzed as the research object. In this regard, the floor heave mechanism and floor control in water-rich soft rock roadways are investigated through laboratory experiments...

In order to predict the change of cutting force in ball helical milling of titanium alloy, considering the kinematics of helical milling and the geometric model of a ball end cutter, the cutting process is divided into three stages, cutting-in, steady, and cutting-out stages, and the shape and volume of undeformed chip in different stages are descr...

Although particle corner breakage has been proved to be the primary mode of particle breakage for coral sand, current studies of pile penetration have continued to present the particle fracture breakage mode, causing the mechanism of pile behaviours in coral sand to remain unclear. This study investigates the particle corner-breakage effect on pile...

This paper presents a numerical investigation of the liquefaction behavior of granular materials considering the initial static shear effects. Two typical cyclic failure modes were identified: cyclic liquefaction and residual deformation accumulation. During the simulation processes, the evolution of the applied work, strain energy, frictional diss...

The paper presents an application of the semi‐analytical differential transform method (DTM) to thermofluidics of generalized Couette flow of couple stress fluid inside a composite channel. The channel comprises a fluid‐saturated porous layer and a clear fluid region. The flow is caused by a uniformly favorable pressure gradient applied at the mout...

Threaded connections make up the majority of separable connections used today. Their disassembly behaviour strongly depends on the conditions during the life-phase. With the trend towards circular economy, disassembly particularly for remanufacturing requires automation. For production systems this mandates a certain capability of adaptation toward...

Based on Galin’s theorem for the indentation of an elastic half-space by a polynomial punch and Barber’s theorem for the determination of the contact area in elastic normal contact problems, an exact contact solution is developed for the frictionless indentation of an elastic half-space by an ellipsoidal power-law punch. Within the Cattaneo–Mindlin...

Plain Language Summary
An accurate prediction of how fast and how far a landslide, such as a debris flow, will travel is essential to define the hazard posed to life and property by these geophysical flows. While dry frictional flows often behave according to the simple physics of friction resisting motion, initially water saturated granular flows...

The particle size of fixed abrasive pad (FAP) is an important factor affecting its machining performance and surface condition. The surface condition of consolidated FAP is closely related to the tribological characteristics. However, the relationship between tribological characteristics of FAP and surface condition has not been studied in depth. T...

The effect of a functional gradient in the cross-section material (FGM) of a thin ribbon-like interfacial deformable inclusion on the stress–strain state of a piecewise homogeneous linear–elastic matrix under longitudinal shear conditions is considered. Based on the equations of elasticity theory, a mathematical model of such an FGM inclusion is co...

The present study investigates the effect of outer diameter (10 mm and 15 mm) and 5 positions of cylindrical vortex generators (CVGs) installed to the wavy channel in order to improve heat transfer parameters in conjunction with low-pressure drops. The wavy channels with and without CVGs are compared in terms of the local heat transfer coefficient,...

The authors investigated tribological characteristics, phase composition of friction surfaces and microhardness of near-surface regions of WC–(Fe–Mn–C) composites with a two-phase (γ + α′) matrix containing 4 % wt. Mn (WC – 80G4), and a single-phase matrix of γ-iron containing 20 % wt. Mn (WC – 80G20) after friction on a disk of high-speed steel at...

The experimental results of Xia and Steen for the contact line dynamics of a drop placed on a vertically oscillating surface are analyzed by numerical phase field simulations. The concept of contact line mobility or friction is discussed, and an angle-dependent model is formulated. The results of numerical simulations based on this model are compar...

The In this experimental study, natural stone powder was utilized to improve a cohesive soil’s compaction and strength properties. According to the significant availability of limestone in the globe, it has been chosen for the purpose of the study, in addition to considering the existing rock industry massive waste. Stone powder was used in percent...

Research in sustainability transitions increasingly acknowledges that the structural characteristics of socio-technical systems differ. However, little attention has been paid to the specific transition dynamics that can result from this structural variation. In response, this paper develops a framework for studying transition dynamics that takes t...

Biofilm heterogeneity and adaptability complicates efforts to link biofilm structural and mechanical properties to frictional drag. As a result, rigid structures are typically used as the benchmark for studying biofilm-associated drag. Elastomeric sandpaper replicas were generated to be used as model systems for investigating the effect of roughnes...

Numerical analyses of the roller–raceway contact have been carried out in a spherical roller bearing using frictional contact models of different complexity. The models used in the study include an implementation of Kalker's exact contact theory named CECT and detailed FE models. The adequacy of the more simplified contact solutions is assessed by...

Wie sind die Entwicklungen der Gender Studies vor dem Hintergrund ihrer Historie zu verstehen? Die Beiträger*innen des Bandes diskutieren diese Frage in drei thematischen Blöcken: Biografische Reflexionen treffen auf politische, künstlerische sowie wissenschaftliche Interventionen und stellen so das Potential der Disziplin heraus. Die einzelnen Bei...

We consider an unsteady non-isothermal flow problem for a general class of non-Newtonian fluids. More precisely the stress tensor follows a power law of parameter p , namely $\sigma = 2 \mu ( \theta , \upsilon , \| D(\upsilon ) \|) \|D( \upsilon ) \|^{p-2} D(\upsilon ) - \pi \mathrm{Id}$ σ = 2 μ ( θ , υ , ∥ D ( υ ) ∥ ) ∥ D ( υ ) ∥ p − 2 D ( υ ) − π...

The expansion liner hanger has great advantages over the traditional slip liner hanger. Therefore, scholars at home and abroad have carried out extensive research on the expansion liner hanger, but there are few researches on the optimization design of the rubber cylinder of the expansion liner hanger. How to select the size and material of the rub...

A mathematical analysis was done to find out the factors that affect the excavating force and power of a chain type trenching machine. The mathematical analysis showed that the excavating force and power of the chain type trenching machine are affected by tool cutting speed, tool-cutting angle, angle between cutting movement and vertical direction,...

The main goal of this paper is to study a class of differential nonlinear system involving parabolic variational and history-dependent hemivariational inequalities in Banach spaces by using the penalty method. We first construct a penalized problem for such a nonlinear system and then derive the existence and uniqueness of its solution to obtain an...

Bearing has been used extensively in numerous applications and their unplanned failure has a consequential effect on the smooth operation of the machinery. A slight misalignment in bearing has a detrimental effect on the smooth running of most machines. Hence, the paper leverages finite element technique to simulate the consequential effect of diff...

A simple approximate theory of snow machining is applied to modelling successive wedge turns of alpine skiing. The model involves predefined control functions describing skier’s control over the turns via angle of attack, edge angle and loading of the skis. To demonstrate the model’s potential, reasonable control functions with a small number of fr...

Diamond is an important material in today and future industry, for its relatively advantages in hardness, optics, heat, and electricity. Strongly impeted by the synthetic low-cost and large-scale manufacturing feasibility, applications of diamond material quickly developed to optical windows, heat transfer, electronic semiconductors, and other high...

Variable gauge rolling is a new process to obtain a plate for which the thickness changes continuously by continuously and dynamically adjusting the roll gap upward and downward in the rolling process. This technology is an effective method for producing lightweight, low-cost, and economical plates. However, variable gauge rolling is an unsteady pr...

Many modern applications rely on the safe operation of components sliding at high speeds, e.g., in the fields of e-mobility, high-speed manufacturing, or impact-resistant materials. While the impact of mechanical energy and heat on the friction and wear behavior of dry metallic interfaces has been the focus of extensive research in the past, the ef...

The Standard Penetration Test (SPT) is the most common in-situ tests for soil investigations. On the other hand, the Cone Penetration Test (CPT) is considered one of the best investigation tools. Many CPT-SPT correlation relationships have been proposed worldwide to estimate soil parameter from the other's available data. However, unfortunately, no...

Background
Identification of sex plays a vital role in forensic and medicolegal investigations. Although several studies were conducted in the past to assess sexual dimorphism in friction ridge skin characteristics, a similar study has not been attempted using creases characteristics. The present study was carried out to determine the sex differenc...

We consider a nonlinear elasticity problem in a bounded domain, its boundary is decomposed in three parts: lower, upper, and lateral. The displacement of the substance, which is the unknown of the problem, is assumed to satisfy the homogeneous Dirichlet boundary conditions on the upper part, and not homogeneous one on the lateral part, while on the...

The synchronizer is a key component of automatic mechanical transmission (AMT) equipped in electric vehicles, but the inertial lock-ring synchronizer (ILRS) commonly used there is not suitable especially for pure electric vehicles without a clutch because of big shift impact. To make the shifting process rapid and smooth, a new synchronizer named p...

There is an urgent demand for novel energetic materials with improved performance to serve as oxygen suppliers (oxidizers) and high-energy additives. Synthesis and characterization of compound that combines both of the above roles, bis-(2-difluoroamino-2,2-dinitroethyl)nitramine (1), is reported. 1 was synthesized by difluor-oamination of bis(2,2-d...

Markush structures are molecular skeletons containing not only specific atoms but also placeholders to represent broad sets of chemical (sub)structures. As genus claims, they allow a vast number of compounds to be claimed in a patent application without having to specify every single chemical entity. While Markush structures raise important questio...

As a hot research topic, nano-scale energetic materials have recently attracted much attention in the fields of propellants and explosives. The preparation of different types of nano-sized energetic materials were carried out, and the effects of nano-sized energetic materials (nEMs) on the properties of solid propellants and explosives were investi...

This paper starts off by the celebrated Knaster–Kuratowski–Mazurkiewicz principle in the formulation by Ky Fan. We provide a novel variant of this principle and build an existence theory for extended real-valued equilibrium problems with general, then monotone and pseudomonotone bifunctions. We develop our existence theory first in general topologi...

A new strut-free retaining wall system, referred to as an inclined-vertical framed retaining wall (IVFRW), is constructed for excavation in clay. It has been successfully used in engineering practice to limit excavation-induced ground movement and protect adjacent buildings. This paper presents the performance of an excavation constructed by using...

As the sawmill industry is moving towards thinner bandsaws for higher yields, it is important to study the cutting force in more detail. The cutting force can be split into two zones. Zone I concerns the force on the major cutting edge as well as the friction force on the major first flank. Zone II considers the forces on the minor cutting edges as...

Afterslip inside a coseismic slip patch is rarely observed, though some previous studies suggest that it is driven by poroelastic rebound (PER). These studies assume constant frictional strength, whereas time-dependent strengthening (healing) of a fault is expected from laboratory experiments, which provide a basis for a rate- and state-dependent f...

Electric load simulator (ELS) systems are employed for electric power steering (EPS) test benches to load rack force by precise control. Precise ELS control is strongly influenced by nonlinear factors. When the steering motor rapidly rotates, extra force is directly superimposed on the original static loading error, which becomes one of the main so...

Running safety of the railway vehicles on the bridge during earthquakes is a major concern for railway engineering. To reduce the derailment risk of railway vehicles on bridges, friction pendulum bearings (FPB) are proposed to be equipped on simply supported bridges in this study. The full nonlinear behavior of the FPB is introduced into the vehicl...

We present a mathematical model of road cycling on arbitrary routes using the Frenet–Serret frame. The route is embedded in the coupled governing equations. We describe the mathematical model and numerical implementation. The dynamics are governed by a balance of forces of gravity, drag, and friction, along with pedalling or braking. We analyse ste...

This paper presents a preliminary field study to investigate the bearing characteristics of grouted micropiles under uplift loading in soft soil. The results show that micropiles with single grouting did not improve the bearing capacity of the piles significantly, mainly because the grouting fluid was lost from the soil pores. However, micropiles w...