Self excited vibrations induced by dry friction pdf

Under certain conditions, the steady state sliding motion becomes unstable. Long after early theoretical predictions of self excited vibration limit cycles by poincar6 and lyapunov minorsky, 1947 postinstabilitythreshold limit cycles offluid induced, self excited lateral vibrations ofrotors havebeendiscussed by. On selfexcited vibrations due to sliding friction in systems of deformable bodies general formulation and influence of contact properties, proceedings of the 7th euromech solid mechanics conference, lisbon, 2009. Friction induced vibrations in railway transportation. The instability leads to the occurrence of stable limitcycle type self excited vibrations. International journal of mechanics instability induced by dry. Self induced chatters friction vibrations pressure induced chatters the self induced chatter is caused by a friction coefficient change with regard to the slip speed. An experimental investigation was conducted in the laboratory with a pinondisk type sliding apparatus to study selfexcited vibrations induced by dry friction. The appearance of selfexcited vibrations caused by dry friction of two elements or their contact surfaces is common practice in nature and technique. Friction induced vibrations of a two degrees of freedom system.

Self excited vibrations are observed in many technical applications. Some mechanical systems have frictional joints where one surface slides on another with dry friction. It is observed that the instability can be suppressed by the tangential highfrequency excitation only for a specific range of strength of excitation. Study of friction induced stickslip phenomenon in a. A selfexcited autoparametric system with dry friction has been submitted to journal. The nonlinear vibration theory and the experimental modal analysis are used in this paper to study the selfexcited vibration of the shellliquid coupled system induced by dry friction. The classical single degreeoffreedom massonmovingbelt model describing frictioninduced vibration is considered, which is generally used to study the.

The characteristics of these vibrations are devided into two groups by the type of friction. A lumped parameter model is presented for studying the dynamic interaction between two disks in relative rotational motion and in friction contact. Selfvibrationinduced wear of a friction pair nasaads. An analysis of the selfexcited torsional vibrations.

We study rotational self excited vibrations of two frictionally coupled disks and consider the case of self excited vibrations arising in the presence of dry friction, where the disk relative velocity periodically changes sign passing through the point of discontinuity of the friction law. Selfexcited vibrations induced by dry friction, part 1. Numerical modeling of frictioninduced vibrations and dynamic instabilities. In 1, 6 it has been analyzed a system with one degree of freedom in. Prevention methods of self excited vibration due to dry friction of vertical rotor yusuke watanabe1, masaji ishii1 isromac 2016 international symposium on transport phenomena and dynamics of rotating machinery hawaii, honolulu april 1015, 2016 abstract recently, because of performance upgrades of rotating machinery, the clearance between. Two different friction coefficients are used, and a normal force pressing the sliding body to a belt depending on an angle bar motion of the analyzed system is applied. Simple analytical approximations are derived for predicting the. However, stability does not improve under normal highfrequency excitations, though amplitude of the self excited oscillation can be controlled to some extent. Interaction between selfexcitation and parametric excitation. Nonlinear behaviour of the friction coefficient results in selfexcited vibration and causes undesirable stickslip oscillations. This paper focuses on the problem of eliminating self excited vibration in a propulsion shafting system induced by the friction of the waterlubricated rubber bearing. The primer and of course the simplest work on dry friction is attributed to coulomb in 1785. The excitation force in the self excited vibration maintaining the action is produced or monitored by the action itself, when the action retarding the excitation force vanishes.

Finally, an illustration on the use of non smooth contact formulation in the. Combining theoretical and experimental modal analyses on selfexcited vibration induced by dry friction between two elastic structures, we can explain the highorder sell excited vibration phenomenon in which water droplets spurt from fourteen or twelve areas of the chinese culture relic dragon washbasin when it is rubbed with hands, and clarify the mechanism of the singular highorder. This classical friction model does not explain all dynamical behaviour observed in mechanical systems with friction. Judder prevents vehicles from starting smoothly, harms the ride comfort, and may produce damage to the drivetrain components. Forced selfexcited vibration with dry friction applied nonlinear. An experimental investigation was conducted in the laboratory with a pinondisk type sliding apparatus to study selfexcited vibrations induced. Interactions among friction, wear, and system stiffness. Dry friction induced self excited vibration between sealing disc and pipe is the source of chatter vibration on pig, and lead to the wear of pigs sealing disc in natural gas pipeline. The appearance of self excited vibrations caused by dry friction of two elements or their contact surfaces is common practice in nature and technique. Self excited vibrations during engagements of dry friction clutches 982846 during the starting of the vehicle, the friction clutch engagement sometimes generates judder. The investigation of the influence of dynamics parameters on. This paper investigates frictioninduced selfexcited vibration in a bistable. A selfexcited friction pair is modeled by a mechanical system of two degreesoffreedom with a normal force varying during the block displacement. Dweib, selfexcited vibrations induced by dry friction.

The physical system, which we are concerned with, is a harmonically excited, dry friction oscillator fig. Typically, high frequency squeal occurs in the frequency range from 8 to 16 khz, while low frequency squeal from 1. Vibration analysis of multi degree of freedom selfexcited. Elimination of frictioninduced vibration of a propulsion.

Second is the presence of positive andor negative feedbacks that lead to dynamic destabilization and frictioninduced vibrations. Selfexcited oscillations in sliding with a constant friction coefficienta simple model. The friction coefficient gradients of todays facings lie between. However, stability does not improve under normal highfrequency excitations, though amplitude of the selfexcited oscillation can be controlled to some extent. Selfexcited vibration represents an important phenomenon in physical and mechanical systems. The braking force that slows down the railway vehicles is associated with dry sliding friction between the brake pads and the wheels. Analytical approaches for friction induced vibration and stability analysis anooshiravan farshidianfar a. Friction contact, frictioninduced vibrations, selfexcited systems. Read statistics of complex eigenvalues in frictioninduced vibration, journal of sound and vibration on deepdyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips. On the periodic response of a harmonically excited dry friction. For example, the mathematical model of selfexcited vibrations, induced by dry friction, requires a nonzero slope of friction characteristic in order to initialize such kind of oscillations babakov 1968. Selfexcited oscillations in sliding with a constant.

This leads to occurrence of self excited vibrations in tread brake unit or simply brake block. Hierarchical organization is the key feature of biological systems, which have capacity for selforganization, selfhealing, and selflubrication, so it is not surprising that hierarchy plays a central role also in. Tribology in industry experimental study of frictional vibrations. This article presents an overview of the acoustics of friction by covering friction sounds, frictioninduced vibrations and waves in solids, and descriptions of other frictional phenomena related to acoustics. So, the system, which is under the self excited vibrations begin to vibrate of their own accord in.

In selfsustained systems, these mechanisms fall into two distinct categories. Index terms self excited vibrations, dry friction, friction instability, limit cycle, stickslip. For dry and wet weather conditions in the wheelrail zone parameters of eq. Selfexcited vibrations induced by dry friction, part 2. Frictioninduced vibration of a lubricated mechanical system. On the periodic response of a harmonically excited dry.

Combining theoretical and experimental modal analyses on selfexcited vibration induced by dry friction between two elastic structures, we can explain the highorder sellexcited vibration phenomenon in which water droplets spurt from fourteen or twelve areas of the chinese culture relic dragon washbasin when it is rubbed with hands, and clarify the mechanism of the. Then the vibration remains sustained at this value. It is thought that this design guides may be useful in the control and reduction of the vibrations induced by dry friction. The characteristics of these vibrations are divided into two groups by the type of friction. One of the typical vibration problem by friction is selfexcited vibration due to. Liu, wang and chen 4 investigated it with nonlinear vibration theory, by modeling and analyz ing the self excited vibration phenomenon 5 caused by dry friction of both the shell. Prevention methods of selfexcited vibration due to dry friction of. The effect of dry friction stickslip coefficients and rubbing velocity on self excited vibration, and the limit cycle and hopf bifurcation solution of the system are obtained. Frictioninduced vibration in a bistable compliant mechanism mdpi. This leads to occurrence of selfexcited vibrations in tread brake unit or simply brake block. Frictioninduced oscillations of a nonasbestos organic.

The vibrations induced by dry friction have been studied by jarvis and mills 4. Study of friction induced stickslip phenomenon in a minimal. Received 3 january 1989 some mechanical systems have frictional joints where one surface slides on. If the inline pdf is not rendering correctly, you can download the pdf file. Chinese culture relic dragon washbasin is a selfexcited one induced by dry friction. Selfexcited oscillations in sliding with a constant friction. Frictioninduced oscillations of a nonasbestos organic pin. Verification of the friction coefficients determining. The presence of selfexcited vibrations itself can be highly detrimental to the performance of me. Conceptually, friction induced vibration can be accomplished only when forceoscillations are accompanied by motion oscillations along the direction of the force oscillations with a suitable relative phase. Several mechanisms have been proposed in the literature to explain frictioninduced vibrations. Friction induced vibration in vehicle clutches and brakes, vehiclebridge interaction and flow induced vibration circular wood saws, cds, dvds, in machining, fluidconveying pipelines are examples of self excited vibration.

Friction induced oscillations result in deterioration of performance of disc brakes and are generally undesired. Timedependent static friction is studied as well as application in a system with 2dof. A harmonically excited dry friction oscillator is examined analytically and. The cause of vibrations is a nonlinear and unknown friction between a drill string and the environment, containing jumps in its characteristics. The formulation accounts for the coupling between the axial and angular. The intensity of self excited vibration is often so high that a save run is impossible and can result in a failure. An experimental investigation was conducted in the laboratory with a pinondisk type sliding apparatus to study self excited vibrations induced by dry friction. Friction is examined from a control system design perspective in 7. A nonlinear friction work formulation for the analysis of selfexcited vibrations. Pdf analysis of selfexcited vibration due to dry friction in a system. Friction, resulting from the sliding contact of solids, often gives rise to diverse forms of waves and oscillations within solids which frequently lead to radiation of sound to the. That means, all type of brake noise originates as a self excited oscillation which is the stickslip phenomenon. Different types of vibrations induced by dry friction are investigated by means of a model apparatus described in part 1. Journal of sound and vibration 1990 72, 177190 selfexcited vibrations induced by dry friction, part 2.

It can have a strong impact on the numerical results and consequently on. Mechanics and nonequilibrium thermodynamics of sliding contact combines the mechanical and thermodynamic methods in tribology, thus extending the field of mechanical friction induced vibrations to nonmechanical instabilities and self organization processes at the frictional interface. It is expected that these vibrations play a role in the behavior of sliding members with dry friction. The formulation accounts for the coupling between the axial and angular motions by. A comparative study on the control of frictiondriven. The nonlinear vibration theory and the experimental modal analysis are used in this paper to study the self excited vibration of the shellliquid coupled system induced by dry friction. There are two different types of chatter vibrations that can occur. We conduct experimental study of friction induced oscillations in a nonasbestos organic material steel pair used in disc brakes of motor vehicles. Effect of highfrequency excitation on friction induced. Index termsself excited vibrations, dry friction, friction instability, limit cycle, stickslip. The effect of dry friction stickslip coefficients and rubbing velocity on selfexcited vibration, and the limit cycle and hopf bifurcation solution of the system are obtained. Furthermore, the result of this study provides an understandable structure for vibroacoustical analysis of selfexcited vibrating systems. Frictioninduced vibrations, a type of selfexcited oscillation refer to 1, 2, are a frequently. International journal of mechanics instability induced by.

Prevention methods of selfexcited vibration due to dry. Self excited vibrations caused by dry friction, which is generally expressed as a function of relative sliding velocities between two solid bodies, are analysed theoretically and observed experimentally. Chinese culture relic dragon washbasin is a self excited one induced by dry friction. Liu, wang and chen 4 investigated it with nonlinear vibration theory, by modeling and analyz ing the selfexcited vibration phenomenon 5 caused by dry friction of both the shell. A one degree of freedom nonlinear dynamics model of self excited vibration induced by dry friction is built firstly, the numerical method is taken to study the impacts of dynamics parameters on self excited vibration. Vibrational interaction of two rotors with friction coupling. Investigation of selfexcited vibrations in tread brake.

The spectra of the oscillations are related to the modal frequencies. A new efficient adaptive control of torsional vibrations. In numerical simulations, the linearised method of feedin energy, calculated purely based on friction work has provided some insights into the physical mechanism for instabilities. Interactions among friction, wear, and system stiffnesspart. Non smooth contact dynamics approach for mechanical. This study deals with a forced self excited vibrating system accompanied by dry friction as an example of a nonlinear system with discontinuities. Analytical approaches for friction induced vibration and. Forced selfexcited vibration with dry friction applied. Self excited vibration of a flexibly supported shafting system in a gravity water tunnel was observed in the testing of friction of waterlubricated rubber bearings. Nonlinear control of frictioninduced selfexcited vibration. The intensity of selfexcited vibration is often so high that a save run is impossible and can result in a failure.

Conceptually, frictioninduced vibration can be accomplished only when forceoscillations are accompanied by motion oscillations along the direction of the force oscillations with a suitable relative phase. Dry frictioninduced selfexcited vibration between sealing disc and pipe is the source of chatter vibration on pig, and lead to the wear of pigs sealing disc in natural gas pipeline. Stickslip vibrations, shooting method, dry friction, discontinuous systems. Frictional contacts are often involved in the mechanism which generates vibrations. Introduction t he dynamic behavior of many tribomechanical systems is in. Experimental investigation on the avoidance of self.

Dweib department of mechanical and aerospace engineering, illinois institute of technology, chicago, illinois 60616, u. Self excited vibrations, dry friction, friction instability, limit cycle, stickslip. Reliable prediction of frictioninduced unstable vibrations such as in brake squeal or hip squeak remains a challenge because of nonlinearities involved and because the complex eigenvalue analysis cea widely. Vibrations are analyzed on indenter on disk system using brass and steel samples as. Selfexcited vibrations are analyzed on the basis of the experimental data. Statistics of complex eigenvalues in frictioninduced. These vibrations are often encountered in practice, with detrimental effects such as excessive wear of components, surface damage, fatigue failure and noise generation. Selfexcited vibrations are observed in many technical applications. A dynamic lagrangian frequencytime method for the vibration of dryfrictiondamped systems. Selfexcited vibrations caused by dry friction, which is generally expressed as a function of relative sliding velocities between two. Considering its occurrence from the historicalpoint of view in the last.

In 51, 52, tondl studied systems consisting of selfexcitations that can. The contact elastic and dissipative characteristics are represented by equivalent stiffness and damping coefficient in the axial as well as torsional direction. That means, all type of brake noise originates as a selfexcited oscillation which is the stickslip phenomenon. They also proposed the use of the shooting method in order to determine periodic solutions of a selfexcited mechanical system subject to frictioninduced vibrations 12. In order to obtain the mechanism of this phenomenon, a 7dof dynamic model of whole vehicle selfexcited vibration induced by the shimmy of front wheels which take the nonlinear factor of tire lateral force and the dry friction force in suspension. Experimental investigation on the avoidance of selfexcited.

Transition to fluidinduced limit selfexcited vibrations of. Nonlinear behaviour of the friction coefficient results in self excited vibration and causes undesirable stickslip oscillations. The major selfexcited vibration mechanisms in the systems with friction can be categorized into three types. Decreasing friction force with increasing relative velocity or negative damping 2. The vibration characteristics are changed when transition occurs from steady state friction. A selfexcited autoparametric system with dry friction. Selfexcited vibrations during engagements of dry friction. The numerical method used here is the direct numerical integral method as we have presented previously, which is a shooting method able to obtain highly accurate periodic solutions of systems with. Highorder selfexcited vibration induced by dry friction. Friction induced vibrations of a two degrees of freedom. However, the dynamics due to friction induced instabilities is highly nonlinear and damping may offset some or all of the excess friction energy provided to the system. As explained above, selfinduced vibrations occur when the friction coefficient decreases while engaging during the slip phase with increasing slip speed in the friction contact. The structural model is obtained from the measurement of the modal frequencies and damping ratios of three degrees of freedom.

Self excited vibrations refer to the interruptions applied to a primarily special group compared to that of the free vibrations or forced vibrations. Introduction the presence of friction induced self sustained vibrations can be highly detrimental to the performance of mechanical systems. A nonlinear friction model for selfexcited vibrations. Stickslip vibrations induced by alternate friction models. This study deals with a forced selfexcited vibrating system accompanied by dry friction as an example of a nonlinear system with discontinuities. The in uence of the interface coe cient of friction upon. When the normal load is further increased, selfexcited periodic vibrations are produced. Modeling method associating generalized polynomial chaos expansion and kriging for mechanical systems. Stick slip phenomenon arises due to alternating elastic and plastic deformation mech anisms in the contact zone. Frictioninduced vibration in vehicle clutches and brakes, vehiclebridge interaction and flowinduced vibration circular wood saws, cds, dvds, in machining, fluidconveying pipelines are examples of selfexcited vibration. Investigation of selfexcited vibrations in tread brake unit. Suppression of selfexcited vibrations in rotating machinery. Selfexcited vibration of whole vehicle with multiple.