Lateral Friction Behavior of a Thin, Tensioned Tape Wrapped Over a Grooved Roller: Experiments and Theory

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Hankang Yang ◽  
Johan B. C. Engelen ◽  
Walter Häberle ◽  
Mark A. Lantz ◽  
Sinan Müftü
Keyword(s):  
Friction Coefficient ◽  
Axial Direction ◽  
Friction Behavior ◽  
Stick Slip ◽  
Friction Forces ◽  
Lateral Dynamics ◽  
Lateral Tape Motion ◽  
Complex Interactions ◽  
Recording Tape ◽  
Effective Friction

Effects of friction forces on the lateral dynamics of a magnetic recording tape, wrapped around a grooved roller are investigated experimentally and theoretically. Tape is modeled as a viscoelastic, tensioned beam subjected to belt-wrap pressure and friction forces. Including the effects of stick and slip and velocity dependence of the friction force render the tape's equation of motion nonlinear. In the experiments, tape was wrapped under tension around a grooved roller in a customized tape path. The tape running speed along the axial direction was set to zero, thus only the lateral effects were studied. The grooved roller was attached to an actuator, which moved the roller across the tape. Tests were performed in slow and fast actuation modes. The slow mode was used to identify an effective static, or breakaway, friction coefficient. In the fast mode, the roller was actuated with a 50 Hz sinusoid. The same effective friction coefficient was deduced from the fast actuation mode tests. This test mode also revealed a periodic stick–slip phenomenon. The stick-to-slip and slip-to-stick transitions occurred when the tape vibration speed matched the roller actuation speed. Both experiments and theory show that upon slip, tape vibrates primarily at its natural frequency, and vibrations are attenuated relatively fast due to frictional and internal damping. This work also shows that an effective friction coefficient can be described that captures the complex interactions in lateral tape motion (LTM) over a grooved roller.

Adhesive Effects on Dynamic Friction for Unlubricated Rough Planar Surfaces

2004 ◽  
Author(s):  
Xi Shi ◽  
Andreas A. Polycarpou
Keyword(s):  
Friction Coefficient ◽  
Mean Value ◽  
Friction Model ◽  
Major Influence ◽  
Dynamic Friction ◽  
Friction Behavior ◽  
Friction Forces ◽  
Normal Contact ◽  
Continuous Contact ◽  
Dynamic Friction Coefficient

As the size of contacting and sliding tribosystems decrease, intermolecular or adhesive forces become significant partly due to nanometer size surface roughness. The presence of adhesion has a major influence on the interfacial contact and friction forces as well as the microtribosystem dynamics and thus influences the overall dynamic friction behavior. In this paper, a dynamic friction model that explicitly includes adhesion, interfacial damping and the system dynamics for realistic rough surfaces was developed. The results show that the amplitude and mean value of the time varying normal contact and friction forces increase in the presence of adhesion under continuous contact conditions. Also, due to the attractive nature of adhesion, its presence delays or eliminates the occurrence of loss of contact. Furthermore, in the presence of significant adhesion, dynamic friction behavior is significantly more complicated compared to the no adhesion case, and the dynamic friction coefficient predictions may be misleading. Thus, it is more appropriate to discuss dynamic friction force instead of dynamic friction coefficient under dynamic conditions.

Friction behavior of waxy oil deposit removal using polymeric bristled brushes

2017 ◽  
Vol 232 (10) ◽  
pp. 1230-1239
Author(s):  
Hang Zhang ◽  
Zhicheng Lan ◽  
Shuhai Liu ◽  
Huaping Xiao
Keyword(s):  
Friction Behavior ◽  
Stick Slip ◽  
Friction Forces ◽  
Waxy Oil ◽  
Removal Experiments ◽  
Three Stages ◽  
Removal Processes ◽  
Wax Deposits ◽  
Slip Phenomenon ◽  
Deposit Removal

Pigging is the most effective and common way to remove the wax deposits in pipelines. The discs, cups, or brushes of a pig are executing components for waxy oil deposit removal. In this study, a homemade experiment setup was built and employed to conduct the waxy oil deposit removal experiments with various wax concentration at different scraping speeds using polymeric bristled brushes. An explanation model was established to analyze the formation of waxy oil deposit chips. The entire removal processes were captured and the resistant friction forces were measured during the experiments. Our results show that there are three stages in the scraping process: (a) brush deforming; (b) steady scraping; (c) brush leaving; In the scraping stage, the frictional resistant force was found to decrease as the scraping speed increases. The frictional resistant force increases as the wax concentration increases. There is obvious stick-slip phenomenon in the steady scraping process. The wax concentration influences the shape of the chips. The shape of the high wax concentration deposit chips is saw-toothed.

A linear differential formulation of friction forces for adaptive estimator algorithms

Robotica ◽  
2001 ◽  
Vol 19 (4) ◽  
pp. 407-421 ◽  
Author(s):  
C. J. Tsaprounis ◽  
N. A. Aspragathos
Keyword(s):  
Differential Equation ◽  
Friction Coefficient ◽  
Control Systems ◽  
Friction Model ◽  
Model Parameters ◽  
Coefficient Function ◽  
Stick Slip ◽  
Friction Forces ◽  
Differential Formulation ◽  
Linear Differential

In this paper a new approach for the formulation of the friction forces velocity function is introduced. The scope of this formulation is to facilitate the implementation of control laws for systems where friction forces appear. The friction model includes the exponential decay part, the Coulomb and viscous friction. The introduced formulation is based on the observation that the friction coefficient function of velocity can be presented as the solution of a linear differential equation. Due to this linearity, the parameters of the derived differential equation can be estimated easily by an adaptive system. The estimation of these parameters is equivalent to the estimation of the friction coefficient in the full range of operational velocities. This knowledge gives to the designed control systems the potential to avoid successfully the stick-slip phenomenon.A control law for one D.O.F. system, where friction appears, is designed in order to prove the applicability of the proposed formulation of the friction model in control systems. A MRAC adaptive algorithm estimates the differential friction model parameters, using the measured friction force, while a sliding controller adjusts the motion of the mechanical system. The proposed friction model can be used in any control system where friction forces have to be compensated. The linear form of the model is suitable for common adaptive estimators. Therefore, the proposed structure is suitable for robotic applications, such as assembly, deburring, etc.

Adhesive Effects on Dynamic Friction for Unlubricated Rough Planar Surfaces

2006 ◽  
Vol 128 (4) ◽  
pp. 841-850 ◽  
Author(s):  
Xi Shi ◽  
Andreas A. Polycarpou
Keyword(s):  
Friction Coefficient ◽  
Mean Value ◽  
Friction Model ◽  
Major Influence ◽  
Dynamic Friction ◽  
Friction Behavior ◽  
Friction Forces ◽  
Normal Contact ◽  
Continuous Contact ◽  
Dynamic Friction Coefficient

As the size of contacting and sliding tribosystems decrease, intermolecular or adhesive forces become significant partly due to nanometer size surface roughness. The presence of adhesion has a major influence on the interfacial contact and friction forces as well as the microtribosystem dynamics (microtribodynamics) and thus influences the overall dynamic friction behavior. In this paper, a dynamic friction model that explicitly includes adhesion, interfacial damping, and the system dynamics for realistic rough surfaces was developed. The results show that the amplitude and mean value of the time varying normal contact and friction forces increase in the presence of adhesion under continuous contact conditions. Also, due to the attractive nature of adhesion, its presence delays or eliminates the occurrence of loss of contact. Furthermore, in the presence of significant adhesion, dynamic friction behavior is significantly more complicated compared to the no adhesion case, and the dynamic friction coefficient predictions may be misleading. Thus, it is more appropriate to discuss dynamic friction force instead of dynamic friction coefficient under dynamic conditions.

On Constitutive Relations for Friction From Thermodynamics and Dynamics

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Michael D. Bryant
Keyword(s):  
Friction Coefficient ◽  
Entropy Production ◽  
Internal Energy ◽  
Coefficient Of Friction ◽  
Slip Velocity ◽  
Constitutive Relations ◽  
Thermodynamic Quantities ◽  
Stick Slip ◽  
Friction Forces ◽  
Kinetic Coefficients

Constitutive and dynamic relations for friction coefficient are presented. A first thrust combines the laws of thermodynamics to relate heat, energy, matter, entropy, and work of forces. The equation sums multiple terms—each with a differential of a variable multiplied by a coefficient—to zero. Thermodynamic considerations suggest that two variables, internal energy and entropy production, must depend on the others. Linear independence of differentials renders equations that yield thermodynamic quantities, properties, and forces as functions of internal energy and entropy production. When applied to a tribocontrol volume, constitutive laws for normal and friction forces, and coefficient of friction are derived and specialized for static and kinetic coefficients of friction. A second thrust formulates dynamics of sliding, with friction coefficient and slip velocity as state variables. Differential equations derived via Newton's laws for velocity and the degradation entropy generation (DEG) theorem for friction coefficient model changes to the sliding interface induced by friction dissipation. The solution suggests that the transition from static to kinetic coefficient of friction with respect to slip velocity for lubricant starved sliding is a property of the motion dynamics of sliding interacting with the dynamics of change of the surface morphology. Finally, sliding with stick-slip was simulated to compare this model to others.

scholarly journals EXPERIMENTAL RESEARCH REGARDING THE INFLUENCE OF THE FRICTION FORCE FROM LINEAR ROLLING GUIDEWAYS ON THE POSITIONING PRECISION OF KINEMATIC FEED CHAINS USED ON CNC MACHINE TOOLS

2017 ◽  
Vol 20 (1) ◽  
Author(s):  
MARIAN FUNARU ◽  
GHEORGHE STAN
Keyword(s):  
Friction Coefficient ◽  
Machine Tools ◽  
High Speed ◽  
Negative Impact ◽  
Cnc Machine Tools ◽  
Cnc Machine ◽  
Stick Slip ◽  
Friction Forces ◽  
Positioning Precision ◽  
Stick Slip Motion

<p>Friction represents one of the major sources of disturbing forces which affect the functioning of the kinematic feed chains from CNC machine tools. Its influence reflects on the positioning precision values, having a negative impact on the table movement and leading to stationary errors, stick-slip motion and trajectory errors. The present paper presents an experimental analysis regarding the influence of the friction forces which appear in the linear rolling guideways on the positioning precision of kinematic feed chains. The rolling guideways present the advantages of a good behavior in terms of axis stability at low speeds and also for achieving high positioning speeds. Concerning the friction coefficient values, rolling and hydrostatic guideways are most suitable for the construction of high speed and high precision kinematic feed chains; in these cases, the friction coefficient has small values, which maintain quasi-constant against the feed rate. </p>

Calculated Behavior and Effective Factors for Bolt Self-Loosening Under a Transverse Cyclic Load Generated by a Linearly Vibrating Washer

2005 ◽  
Author(s):  
Yasuo Fujioka ◽  
Tomotsugu Sakai
Keyword(s):  
Surface Roughness ◽  
Friction Coefficient ◽  
Contact Pressure ◽  
Common Knowledge ◽  
Axial Direction ◽  
Element Analysis ◽  
Friction Coefficients ◽  
Friction Forces ◽  
Contact Surfaces ◽  
The Individual

It is common knowledge that a bolt is apt to loosen due to slippage between the contact surfaces of joined parts. Loosening tests using real parts enable precise scrutiny of real phenomena under the influence of multiple factors such as slip distance, surface roughness, and coefficient friction. However, estimating the influence of the individual factors is very difficult because the friction forces of real contact surfaces are compiled based on variations in friction coefficients, meaning friction is not stable. Therefore, the effects of factors were investigated using Finite Element Analysis (FEA) to control friction coefficients. The procedures were as follows. Assuming a joined structure consisting of a bolt, nut, and washer, bolt axial tension was generated through constant movement of a washer in the bolt’s axial direction, following which the washer was constantly vibrated in one direction transverse to the bolt axis. This vibration generated displacements equivalent to the degree of slippage between the two clamped parts. During vibration, the rotating angles of the bolt and the contact pressure of the threads and bearing surfaces were calculated. The results were as follows. The vibrating displacements of a washer have considerable influence on the rotational loosening of a bolt. In cases where there was only minor displacement of the washer vibrations, the rotational loosening angle rapidly decreased, although the loosening did not cease completely. Therefore, the magnitude of what is called “critical slip” was not confirmed under the conditions of this study. In addition, the friction coefficient has a significant influence on the rotational loosening of a bolt. When the respective friction coefficient values of the threads and bearing surfaces are not balanced, rotational loosening cannot continue. Surface roughness readily affects contact pressure, so it tends to make the contact pressure localized. In particular, high-pressure areas were affected by several projections set on the threads. However, under those conditions the rotational loosening did not differ greatly from the results of the fine surface models subject to the same vibrating amplitude and friction coefficient. Consequently, the localized contact pressure had little evident effect on loosening. Above all, FEA reproduced the loosening of the bolt, and the reference made in this analysis is useful.

scholarly journals Relationship between the real contact behavior and tribological characteristics of cotton fabric

Friction ◽  
2020 ◽  
Author(s):  
Rongxin Chen ◽  
Jiaxin Ye ◽  
Wei Zhang ◽  
Jiang Wei ◽  
Yan Zhang ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Contact Area ◽  
Dynamic Change ◽  
Tribological Characteristics ◽  
Real Contact Area ◽  
Cotton Fibers ◽  
Friction Behavior ◽  
Contact Behavior ◽  
The Real ◽  
Real Contact

Abstract The tribological characteristics of cotton fibers play an important role in engineering and materials science, and real contact behavior is a significant aspect in the friction behavior of cotton fibers. In this study, the tribological characteristics of cotton fibers and their relationship with the real contact behavior are investigated through reciprocating linear tribotesting and real contact analysis. Results show that the friction coefficient decreases with a general increase in load or velocity, and the load and velocity exhibit a co-influence on the friction coefficient. The dynamic change in the real contact area is recorded clearly during the experiments and corresponds to the fluctuations observed in the friction coefficient. Moreover, the friction coefficient is positively correlated with the real contact area based on a quantitative analysis of the evolution of friction behavior and the real contact area at different loads and velocities. This correlation is evident at low velocities and medium load.

An improved nonlinear model considering relative velocity for the friction behavior between untwisted glass-fiber tow and roller

2021 ◽  
pp. 004051752110308
Author(s):  
Yang Liu ◽  
Zhong Xiang ◽  
Xiangqin Zhou ◽  
Zhenyu Wu ◽  
Xudong Hu
Keyword(s):  
Friction Coefficient ◽  
Glass Fiber ◽  
Relative Velocity ◽  
Friction Model ◽  
Woven Fabric ◽  
Test Results ◽  
Application Process ◽  
Friction Behavior ◽  
Improved Model

Friction between the tow and tool surface normally happens during the tow production, fabric weaving, and application process and has an important influence on the quality of the woven fabric. Based on this fact, this paper studied the influence of tension and relative velocity on the three kinds of untwisted-glass-fiber tow-on-roller friction with a Capstan-based test setup. Furthermore, an improved nonlinear friction model taking both tension and velocity into account was proposed. According to statistical test results, firstly, the friction coefficient was found to be positively correlated with tension and relative velocity. Secondly, tension and velocity were complementary on the tow-on-roller friction behavior, with neither being superior to the other. Thirdly, an improved model was found to present well the nonlinear characteristics between friction coefficient and tension and velocity, and predicational results of the model were found to agree well with the observations from Capstan tests.

A novel technique for modeling friction behavior in knitted fabric simulation

2017 ◽  
Vol 29 (6) ◽  
pp. 776-792
Author(s):  
Vajiha Mozafary ◽  
Pedram Payvandy
Keyword(s):  
Friction Coefficient ◽  
Uniform Distribution ◽  
Friction Force ◽  
Experimental Result ◽  
Knitted Fabric ◽  
Friction Behavior ◽  
Content Type ◽  
Novel Technique ◽  
Fabric Structure ◽  
Fabric Surface

Purpose Fabric-object friction force is a fundamental factor in cloth simulation. A large number of parameters influence the frictional properties of fabrics such as fabric structure, yarn structure, and inherent properties of component fibers. The purpose of this paper is to propose a novel technique for modeling fabric-object friction force in knitted fabric simulation based on the mass spring model. Design/methodology/approach In this technique, unlike other studies, distribution of friction coefficient over the fabric surface is not uniform and depends on the fabric structure. The main reason for considering non-uniform distribution is that in various segments of fabric, contact percent of fabric-object is different. Findings The proposed technique and common methods based on friction coefficient uniform distribution are used to simulate the frictional behavior of knitted fabrics. The results show that simulation error values for proposed technique and common methods are 2.7 and 9.4 percent as compared with the experimental result, respectively. Originality/value In the existing methods of the friction force modeling, the friction coefficient of fabric is assumed uniform. But this assumption is not correct because fabric does not have an isotropic structure. Thus in this study, the friction coefficient distribution is considered based on fabric structure to achieve more of realistic simulations.

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