Numerical Analysis of Intermittent Stick-Slip Behaviour of Tube-Support Interaction in Heat-Exchangers

2012 ◽  
Author(s):  
Reza Azizian ◽  
Njuki Mureithi
Keyword(s):  
Heat Exchangers ◽  
Friction Model ◽  
Fretting Wear ◽  
System Response ◽  
Coefficient Function ◽  
Lugre Model ◽  
Stick Slip ◽  
Friction Forces ◽  
Stribeck Effect ◽  
Slip Region

Flow induced excitation forces in heat exchangers cause tube-support interactions. The long-term interaction is an important phenomenon which may cause fretting-wear of the tubes. Experimental tests of the interaction show the occurrence of stick-slip intermittent behavior in the tube response. Many factors are involved to precisely predict the interaction behavior including flow excitation forces, impact and friction forces. One of the explanations behind the intermittent stick-slip behavior may be interpreted by refinements in the conceptual choice of friction model and coefficient of friction. Therefore, among the factors above, the incorporated friction model plays an important role in the determination of the level of fretting-wear in the system. The friction model should satisfy two important criteria: the first important aspect is the strategy of the friction model to detect the cessation of sticking, the beginning of partial slipping and establishment of the sliding region. The second important aspect is defining a friction coefficient function for the entire system response to precisely represent the transient stick-slip regions. In the present work, the velocity limited friction model was compared with the LuGre model which is a rate dependent friction model. The effect of varying the break-away force and Stribeck effect on the stick-slip region was also investigated. Furthermore, the criteria to demarcate the stick-slip region in the LuGre model are discussed and a different method to incorporate the Stribeck effect and presliding damping in the Dahl friction model are proposed. Finally, a new hybrid spring-damper friction model inspired by the Cattaneo-Mindlin stress distribution in the contact region is proposed.

Numerical Analysis of Fretting-Wear With a Hybrid Elastoplastic Friction Model

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Reza Azizian ◽  
Njuki Mureithi
Keyword(s):  
Experimental Tests ◽  
Friction Model ◽  
Fretting Wear ◽  
System Response ◽  
Coefficient Function ◽  
Lugre Model ◽  
Stick Slip ◽  
Stribeck Effect ◽  
Intermittent Behavior ◽  
Slip Region

Fretting-wear is a common problem in different industries, especially when it comes to interactions between metallic components. Flow-induced excitation forces in heat exchangers for instance cause tube-support interactions. The long-term interaction is an important phenomenon, which may cause fretting-wear of the tubes. Experimental tests of the interaction show the occurrence of stick–slip intermittent behavior in the tube response. To precisely simulate the intermittent stick–slip behavior, it is crucial to refine the conceptual model of the coefficient of friction for the entire motion from absolute zero velocity to gross slip phase. The incorporated friction model plays an important role in the determination of the level of fretting-wear in the system. The friction model should satisfy two important criteria. The first important aspect is the strategy of the friction model to detect the cessation of sticking, the beginning of partial-slipping, and establishment of the sliding region. The second important aspect is defining a friction coefficient function for the entire system response to precisely represent the transient stick–slip regions. In the present work, the velocity-limited friction model was compared with the LuGre model, which is a rate-dependent friction model. The effect of varying the break-away force and Stribeck effect on the stick–slip region were also investigated. Furthermore, the criteria to demarcate the stick–slip region in the LuGre model are discussed, and a different method to incorporate the Stribeck effect and presliding damping in the Dahl friction model is proposed. Using the tangential stress distribution in the contact area, a new hybrid spring-damper friction model is developed. The model is able to estimate the elastic, plastic, and partial-slipping distances during the relative motion. The ability of the model to reproduce experimental tests is investigated in the present work.

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.

A Hybrid Friction Model for Dynamic Modeling of Stick-Slip Behaviour

2013 ◽  
Author(s):  
Reza Azizian ◽  
Njuki Mureithi
Keyword(s):  
Stress Distribution ◽  
Relative Motion ◽  
Contact Area ◽  
Heat Exchangers ◽  
Experimental Tests ◽  
Friction Model ◽  
Fretting Wear ◽  
Stick Slip ◽  
Slip Distance

Fretting wear is a common problem in different industries especially when it comes to interactions between metallic components. In heat exchangers, the problem plays a destructive role due to long term interaction between tubes and supports which may consequently lead to tube failure. In the present work, the tube-support fretting wear problem was investigated by refining models for friction effects in the stick-slip regions. The Slip distance is the most important parameter for wear estimation. Using the tangential stress distribution in the contact area, a new hybrid spring-damper friction model was developed. The model is able to estimate elastic, plastic and partial slipping distances during relative motion. The ability of the model to reproduce experimental tests is investigated in the present work.

On the Application of the Lu-Gre Model to Simulate Joint Friction in Multi-Body Systems

2011 ◽  
Author(s):  
Kedar Gajanan Kale ◽  
Rajiv Rampalli
Keyword(s):  
Friction Model ◽  
Lugre Model ◽  
Friction Forces ◽  
Joint Friction ◽  
Modeling Techniques ◽  
Static Regime ◽  
Increasing Demand ◽  
Automotive Suspension ◽  
Multi Body

Advances in the application of multi-body simulation technology to real world problems have led to an ever increasing demand for higher fidelity modeling techniques. Of these, accurate modeling of friction is of strategic interest in applications such as control system design, automotive suspension analysis, robotics etc. Joints (sometimes referred to as constraints) play an important role in defining the dynamics of a multi-body system. Hence, it is imperative to accurately account for friction forces arising at these joints due to the underlying interface dynamics. In this paper, we discuss the application of LuGre, a dynamic friction model to simulate joint friction. We choose the LuGre model due to its ability to capture important effects such as the Stribeck effect and the Dahl effect. The native 1-d LuGre model is extended to formulate friction computations for non-trivial joint geometries and dynamics in 2 and 3 dimensions. It is also extended to work in the quasi-static regime. Specific applications to revolute, cylindrical and spherical joints in multi-body systems are discussed. Finally, an engineering case study on the effects of joint friction in automotive suspension analysis is presented.

Vibration and Analysis of Multi-Disk Friction Systems

1998 ◽  
Author(s):  
Henric Larsson ◽  
Kambiz Farhang
Keyword(s):  
Frictional Contact ◽  
Vibration Characteristics ◽  
Lumped Parameter Model ◽  
Stick Slip ◽  
Friction Forces ◽  
Lumped Parameter ◽  
Modes Of Vibration ◽  
The Coefficient Of Friction ◽  
Slip Region ◽  
Stiffness And Damping

Abstract The paper presents a lumped parameter model of multiple disks in frictional contact. The contact elastic and dissipative characteristics are represented by equivalent stiffness and damping parameters in the axial as well as the torsional directions. The formulation accounts for the coupling betwen the axial and angular motions by viewing the contact normal force to be the result of axial behavior of the system. The frictional contact of two disks in contact is modeled in two dynamic states (i.e. sticking and slipping state) having individual lumped parameter models and the conditions that control the switching between the two states are established. The friction forces are represented by assuming the coefficient of friction to be a function of the sliding velocity, varying exponentially from its static value at zero relative velocity to its kinetic value at high velocities. A computer simulation of an eight-rotor disk assembly is presented. The torsional vibration characteristics and how it is liked to the axial modes of vibration is analyzed. The vibration characteristics in the transient, steady-state and stick-slip region is compared. In the stick-slip region, the angular velocity of the interfaces in frictional contact is depicted and the sticking and slipping states are defined. It is shown that the duration of slip is approximately constant and the duration of stick increases almost exponentially until a final sticking is achieved.

Experimental Validation of a 2D Bristle Friction Force Model

2010 ◽  
Author(s):  
Steven Fillmore ◽  
Jianxun Liang ◽  
Ou Ma
Keyword(s):  
Friction Model ◽  
Contact Friction ◽  
Force Model ◽  
Tangential Plane ◽  
Stick Slip ◽  
Friction Forces ◽  
Body Contact ◽  
Point Of Interest ◽  
Experimental Effort ◽  
Sliding Regimes

This paper describes an experimental effort designed to validate a general 2D bristle contact friction model. The model extends the 1D integrated bristle friction model to a 2D space by allowing the “bristle spring” to not only stretch along the direction of the bristle displacement but also rotate due to the instantaneous direction change of the velocity or motion trend in the common tangential plane of the contacting surfaces involved at the point of interest. The model is capable of simulating frictional behaviour in both sliding and sticking regimes occurring in general 3D rigid-body contact. With such an extension, the resulting friction model can be readily used to compute 3D contact friction forces in both sticking and sliding regimes. Two experiments were designed and implemented to validate the new 2D bristle model. The experiments were able to passively produce common frictional phenomena such as sliding, sticking, and stick-slip.

Dynamics Modeling of Nanoparticle in AFM-Based Manipulation Using Two Nanoscale Friction Models

2009 ◽  
Author(s):  
Hesam Babahosseini ◽  
Seyed Hanif Mahboobi ◽  
Ali Meghdari
Keyword(s):  
Normal Force ◽  
Dynamics Modeling ◽  
Lugre Model ◽  
Stick Slip ◽  
Interaction Forces ◽  
Friction Forces ◽  
Lumped Model ◽  
Atomic Force ◽  
Friction Models ◽  
Afm Probe

Application of atomic force microscope (AFM) as a manipulator for pushing-based positioning of nanoparticles has been of considerable interest during recent years. Nevertheless comprehensive researches has been done on modeling and the dynamics analysis of nanoparticle behavior during the positioning process. The development of dynamics modeling of nanoparticle is crucial to have an accurate manipulation. In this paper, a comprehensive model of pushing based manipulation of a nanoparticle by AFM probe is presented. The proposed nanomanipulation model consists of all effective phenomena in nanoscale. Nanoscale interaction forces, elastic deformation in contact areas and friction forces in tip/particle/substrate system are considered. These effects are utilized to derive governing dynamics of the lumped model of AFM and nanoparticle during the manipulation process. The utilized friction models are a modified Coulomb approach and Lund-Grenoble (LuGre) model. The former is a combination of both normal force and contact surface area. The latter is dependent on the velocity of the nanoparticle and leads to stick-slip behavior of the nanoparticle. Finally, the compatibility and effectiveness of the two proposed models are simulated and compared.

Modeling and Simulation of the Swing System of Crawler-Type Medium Hydraulic Excavator Using Dynamic Friction Model

2014 ◽  
Author(s):  
Ji-Min Lee ◽  
Jae-Hong Cho ◽  
Jae-Hyeong Yoo
Keyword(s):  
Cross Correlation ◽  
Static Friction ◽  
Friction Model ◽  
Hydraulic Excavator ◽  
Dynamic Friction ◽  
Analysis Model ◽  
Lugre Model ◽  
Simulation Accuracy ◽  
Stribeck Effect ◽  
System A

An analysis model is presented in this paper to simulate the dynamics of the swing system of crawler-type medium hydraulic excavator. It is found from experiments that the static friction model cannot simulate actual friction phenomena such as the Stribeck effect which can be observed in real swing system. A dynamic friction model, i.e., the simplified LuGre model, has been implemented for more accurate simulation in the theoretical analysis. The validity of the simulation model adopting the dynamic friction model has been verified by comparing in time domain the simulated swing angle with that from actual swing test. Cross-correlation between the simulated and measured swing angles turned out to be 0.92. It can be concluded, therefore, that the proposed dynamic friction model considerably improves the simulation accuracy.

A New Tube/Support Impact Model for Heat Exchanger Tubes in Loose Supports

2003 ◽  
Author(s):  
M. A. Hassan ◽  
D. S. Weaver ◽  
M. A. Dokainish
Keyword(s):  
Heat Exchanger ◽  
Contact Stiffness ◽  
Single Point ◽  
Friction Model ◽  
Fretting Wear ◽  
Analytical Models ◽  
Stick Slip ◽  
Proposed Model ◽  
Flow Induced Vibrations ◽  
Wear Damage

Heat exchanger tubes are usually loosely supported at intermediate points by plates or flat bars. Flow-induced vibrations result in fretting wear tube damage due to impacting and rubbing of tubes against their supports. Prediction of tube response relies on modelling the nonlinear tube/support interaction. The evaluated response is used to predict the resultant wear damage using experimentally measured wear coefficients. An accurate of prediction of impact forces and the work rate is therefore paramount. The analytical models available assume tube/support contact occurs over a single point. In this paper, a computational algorithm is proposed to describe the tube/support impact considering a finite support width. The new model provides a means of representing tube/support contact as a combination of edge and segmental contact. The proposed model utilizes a distributed contact stiffness to describe the segmental contact. The formulation also incorporates a stick/slip friction model. The model developed is utilized to simulate the dynamics of loosely-supported tubes.

A Nonlinear Friction Model for an Electromechanical Actuator Valve

2015 ◽  
Vol 799-800 ◽  
pp. 1096-1101
Author(s):  
Zsolt Horváth
Keyword(s):  
Fault Detection ◽  
Linear Model ◽  
Friction Model ◽  
Experimental Results ◽  
Experimental Setup ◽  
Nonlinear Friction ◽  
Stick Slip ◽  
Stribeck Effect ◽  
Throttle Valve ◽  
Friction Models

In this work we have extended a basic linear model of the Electromechanical Throttle Valve to a nonlinear friction model, which captures the most important friction phenomenon of interest for fault detection. In our examination we have implemented the Tustin’s friction model. This nonlinear friction model has only 4 parameters but describes the friction phenomenon of the Stribeck effect also it includes both the Stick and Slip regimes. To the validation of the actuator model and examination of the friction models we have performed experiments using the experimental setup of NI LabVIEW CompactRIO. The friction phenomenon as hysteresis, stick-slip and Stribeck effects, are an interest for fault detection of the Actuator Valve. The experimental results have shown, that Tustin’s model provides a good approach for modeling of the friction behaviour of the Electromechanical Throttle Valve.

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