Nonlinear Transient Dynamics of Pendulum Torsional Vibration Absorbers—Part II: Experimental Results

2013 ◽  
Vol 135 (1) ◽  
Author(s):  
Ryan J. Monroe ◽  
Steven W. Shaw
Keyword(s):  
Torsional Vibration ◽  
Companion Paper ◽  
Experimental Results ◽  
Circular Path ◽  
Vibration Absorbers ◽  
Automotive Engine ◽  
Engine Order ◽  
Applied Torque ◽  
Centrifugal Pendulum Vibration Absorbers ◽  
Nonlinear Transient

This paper presents results from an experimental investigation of the transient response of centrifugal pendulum vibration absorbers, including a comparison with the analytical results derived in the companion paper, Part I. The focus of the study is the overshoot experienced by pendulum-type torsional vibration absorbers when a rotor running at a constant speed is suddenly subjected to an applied fluctuating torque. The experiments are carried out using a fully instrumented spin rig controlled by a servo motor that can provide user-specified engine order disturbances, including those that simulate automotive engine environments. The absorber overshoot depends on the absorber tuning relative to the excitation order, the absorber damping, the amplitude of the applied torque, and on the system nonlinearity, which is set by the absorber path and/or kinematic coupling between the rotor and the absorber. Two types of absorbers are used in the study, a simple circular path pendulum, for which the path nonlinearity is dominant, and a nearly tautochronic path pendulum with a bifilar support, for which the path and coupling nonlinearities are both small. It is found that the experimental results agree very well with the analytical predictions from the companion paper. In addition, it is confirmed that the general path pseudoenergy prediction (which depends on a single parameter) provides a useful, conservative upper bound for most practical absorber designs, provided the absorber damping is small.

Nonlinear Transient Dynamics of Pendulum Torsional Vibration Absorbers

2011 ◽  
Author(s):  
Ryan J. Monroe ◽  
Steven W. Shaw
Keyword(s):  
Equations Of Motion ◽  
Torque Converter ◽  
Transient Dynamics ◽  
Circular Path ◽  
Vibration Absorbers ◽  
Approximate Analytical Expression ◽  
Centrifugal Pendulum Vibration Absorbers ◽  
Nonlinear Transient ◽  
System Equations ◽  
Minimal Mass

This paper describes an analytical and experimental investigation of the transient dynamics of centrifugal pendulum vibration absorbers, which are used for reducing torsional vibrations in rotating machines. Recently these absorbers have been proposed for use in automotive engines, to aid with fuel saving technologies such as cylinder deactivation and torque converter lockup. In order for them to operate effectively with minimal mass, they must be designed to allow for large amplitude, nonlinear responses. In this paper we consider the transient dynamics of these absorbers, focusing on the response during startup. During these transient events the absorbers experience a beating type motion, resulting in overshoot of the absorber response before reaching steady state conditions. Using a perturbation analysis of the system equations of motion, an approximate analytical expression for nonlinear overshoot is derived, relating the overshoot to the system and excitation parameters. These predictive results are derived for a general class of absorbers, and are verified by simulations of the full equations of motion and by experiments using a fully instrumented spin rig. It is found that the overshoot for absorbers with softening nonlinearity, such as circular path absorbers, can be well over the 100% upper limit for a linear absorber, and can be as high as 173%. For absorbers with tautochronic paths, the overshoot remains quite close to that of the linearized system, even for large amplitudes. These results provide a useful tool for the design of absorbers to meet transient response specifications.

Nonlinear Dynamics of Flexible Rotating Shafts With Centrifugal Pendulum Vibration Absorbers

2015 ◽  
Author(s):  
Mustafa A. Acar ◽  
Steven W. Shaw ◽  
Brian F. Feeny
Keyword(s):  
Torsional Vibration ◽  
Perturbation Methods ◽  
Natural Frequencies ◽  
Rotation Speed ◽  
Vibration Modes ◽  
Vibration Absorbers ◽  
Engine Order ◽  
Centrifugal Pendulum Vibration Absorbers ◽  
Rotating Shafts ◽  
Practical Implications

We consider the nonlinear vibration response of rotating flexible shafts fitted with centrifugally driven pendulum vibration absorbers (CPVAs) that are used to address engine-order torsional vibrations. The model used to represent the behavior of the flexible shaft consists of two lumped inertial elements with an interconnecting stiffness element, which captures the rigid body and fundamental torsional vibration modes of the rotor. The absorbers are centrifugally driven pendulums fitted to a rotor element, such that their natural frequencies scale with the rotor speed, and can thus tuned to a given order of rotation. Previous analysis of a linearized version of this coupled rotor-absorber system revealed frequency veering behavior as the rotation speed varies, and showed that one can detune the absorber to eliminate key system resonances. In this paper the behavior of the system is analyzed for large absorber amplitudes using perturbation methods and numerical simulations. It is shown that the absorbers remain effective in reducing torsional vibration when moving through large amplitudes, and that the resonance avoidance is similarly robust. This has practical implications for the tuning of absorbers in certain applications.

Experimental Investigation of a System With Multiple Nearly Identical Centrifugal Pendulum Vibration Absorbers

2003 ◽  
Author(s):  
Tyler M. Nester ◽  
Alan G. Haddow ◽  
Steven W. Shaw
Keyword(s):  
Experimental Investigation ◽  
Theoretical Background ◽  
Experimental Results ◽  
Circular Path ◽  
Vibration Absorbers ◽  
Test Apparatus ◽  
Controlled Experiments ◽  
Theoretical Predictions ◽  
Centrifugal Pendulum Vibration Absorbers ◽  
First Time

This paper presents experimental results from tests completed on a rotor system fitted with nearly-identical circular path centrifugal pendulum vibration absorbers. A brief review of theoretical background for the absorbers is given along with an overview of the test apparatus. The experimental results for one absorber and for four absorbers are presented and compared with theoretical predictions and expectations. To the best knowledge of the authors, this is the first time that systematic, controlled experiments that monitored both the response of the absorbers and the rotor have been undertaken.

Torsional Vibration Suppression by a Centrifugal Pendulum Vibration Absorber

2005 ◽  
Author(s):  
Yukio Ishida ◽  
Tsuyoshi Inoue ◽  
Taishi Kagawa ◽  
Motohiko Ueda
Keyword(s):  
Torsional Vibration ◽  
Large Amplitude ◽  
Vibration Suppression ◽  
Torsional Vibrations ◽  
Vibration Absorbers ◽  
Harmonic Vibrations ◽  
Centrifugal Pendulum Vibration Absorbers ◽  
Automobile Engines ◽  
Large Amplitude Vibration ◽  
Driving Torque

Driving torque of rotating machinery, such as automobile engines, changes periodically. As a result, torsional vibrations occur and cause serious noise and vibration problems. In this study, the dynamic characteristics of centrifugal pendulum vibration absorbers restraining torsional vibration is investigated both theoretically and experimentally. In the theoretical analysis, the nonlinear characteristics are taken into consideration under the assumption of large amplitude vibration of pendulum. It is clarified that the centrifugal pendulum, although it has remarkable effects on suppressing harmonic vibration, induces large amplitude harmonic vibrations, the second and third superharmonic resonances, and unstable vibrations of harmonic type. We propose various methods to suppress these secondarily induced vibration and show that it is possible to suppress torsional vibrations to substancially zero amplitude in all through the rotational speed range.

Nonlinear Aspects of the Performance of Centrifugal Pendulum Vibration Absorbers

1964 ◽  
Vol 86 (3) ◽  
pp. 257-263 ◽  
Author(s):  
D. E. Newland
Keyword(s):  
Torsional Vibration ◽  
Large Amplitude ◽  
Vibration Absorbers ◽  
Aircraft Engines ◽  
Reciprocating Engines ◽  
Centrifugal Pendulum Vibration Absorbers ◽  
Large Amplitude Motion

Centrifugal pendulums have been used for many years to limit the torsional vibration of reciprocating engines. Recently small pendulums, designed to swing through amplitudes of about 45 deg, have been tested for lightweight aircraft engines. These have not functioned properly, and have been found to swing through much larger angles than expected, damaging the stops limiting motion of the pendulum counterweight. This paper investigates the large-amplitude motion of centrifugal-pendulum vibration absorbers.

scholarly journals Developments in the Design of Centrifugal Pendulum Vibration Absorbers

2020 ◽  
Vol 25 (2) ◽  
pp. 266-277
Author(s):  
David E. Newland
Keyword(s):  
Torsional Vibration ◽  
System Performance ◽  
Vibration Absorbers ◽  
Aircraft Engines ◽  
Current State ◽  
Practical Design ◽  
Centrifugal Pendulum Vibration Absorbers ◽  
Automobile Engines ◽  
The Subject ◽  
Design Requirements

For over 60 years, the torsional vibration of reciprocating aircraft engines has been controlled by centrifugal pendulum vibration absorbers. Loose weights attached to an engine's crankshaft act as tuned-mass absorbers by oscillating at a frequency in proportion to rotational speed. More recently, similar loose masses have been attached to the flywheels of automobile engines. The need to achieve increased power from fewer cylinders, while reducing weight and improving economy, has exacerbated torsional vibration of the drive train. The dynamics of a wheel carrying many centrifugal pendulums of bifilar design has been the subject of a growing literature, but much less has been written about roller-type pendulums and about overall system performance. This paper is a new analysis of bifilar and roller systems and their design requirements. The current state of knowledge about practical design limitations is explained and the need for further research discussed.

Nonlinear Localization in Systems of Tautochronic Vibration Absorbers

1997 ◽  
Author(s):  
Chang-Po Chao ◽  
Steven W. Shaw
Keyword(s):  
Dynamic Instability ◽  
Vibration Absorbers ◽  
Worst Case ◽  
Nonlinear Localization ◽  
Synchronous Motion ◽  
Applied Torque ◽  
Centrifugal Pendulum Vibration Absorbers ◽  
Autonomous Differential Equations ◽  
Steady State Solutions ◽  
Angular Transformation

Abstract The system considered consists of a rigid rotor and N centrifugal pendulum vibration absorbers (CPVAs) riding on epicycloidal paths tuned to order n, the same as the dominant order of the applied torque. An investigation is carried out to determine the effects that a dynamic instability of the synchronous motion of CPVAs has on the system performance. Using various co-ordinate transformations, including a group-theory-based transformation and an angular transformation, the system dynamics are modeled by a set of 2N first-order, averaged, autonomous differential equations. A bifurcation analysis of these equations shows that in the post-bifurcation dynamic, one of the N absorbers moves out of step and at a much larger amplitude than its partners. This localized response is dynamically stable and leads to the worst-case (that is, the smallest) operating torque range of all the possible post-critical steady-state solutions. Analytical estimates of the torque range and the rotor acceleration are derived based on a truncated version of the equations, and more accurate estimates are obtained from a numerical solution of the non-truncated equations. The results are found to be very accurate when compared to numerical simulations.

The Effects of Gravity on the Response of Centrifugal Pendulum Vibration Absorbers

2021 ◽  
pp. 1-61
Author(s):  
Darryl Tchokogoue ◽  
Ming Mu ◽  
Brian F. Feeny ◽  
Bruce K. Geist ◽  
Steven W. Shaw
Keyword(s):  
Equations Of Motion ◽  
Operating Conditions ◽  
Vibration Absorbers ◽  
Cyclic Symmetry ◽  
Passive Devices ◽  
Engine Order ◽  
Gravity Effects ◽  
Centrifugal Pendulum Vibration Absorbers ◽  
Automotive Powertrain ◽  
Linearized Model

Abstract This paper describes the effects of gravity on the response of systems of identical, cyclically arranged, centrifugal pendulum vibration absorbers (CPVAs). CPVAs are passive devices composed of movable masses suspended on a rotor, suspended such that they reduce torsional vibrations at a given engine order. These absorbers are becoming prevalent in automotive powertrain components in order to expand fuel-efficient engine operating conditions. Gravitational effects acting on the absorbers can be important for a horizontal rotor/CPVA system spinning at relatively low rotation speeds, for example, during engine idle conditions. The main goal of this investigation is to predict the response of a CPVA/rotor system in the presence of gravity. A linearized model which includes the effects of gravity and an order n torque acting on the rotor is analyzed by exploiting the cyclic symmetry of the system. The results show that the N absorbers respond in one or more groups, where the absorbers in each group respond with identical waveforms but shifted phases. The number of groups depends on the engine order n and the ratio Nn. It is shown that there are special resonant effects if the engine order is n = 1 or n = 2, the latter of which is particularly important in applications. In addition, it is shown that for N > 1 the rotor response is not affected by gravity, due to the symmetry of the gravity effects. The analytical predictions are verified by direct simulations of the equations of motion.

Torsional Vibration Suppression by Roller Type Centrifugal Vibration Absorbers

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
Yukio Ishida ◽  
Tsuyoshi Inoue ◽  
Tomohiko Fukami ◽  
Motohiko Ueda
Keyword(s):  
Torsional Vibration ◽  
Vibration Suppression ◽  
Vibration Absorbers ◽  
Nonlinear Dynamical ◽  
Dynamical Characteristics ◽  
Centrifugal Pendulum Vibration Absorbers ◽  
Automobile Engines ◽  
Long Time ◽  
The Difference

Centrifugal pendulum vibration absorbers (CPVA) have been used for a long time as a method to suppress torsional vibration. Recently, roller type CPVA, that has a similar characteristic but simpler structure, have been investigated and started to be used in some automobile engines. However, only the linear dynamical characteristics of the roller type CPVA have been focused, and the influence of the nonlinearity affecting on vibration suppression has not been clarified. This study mainly focuses on the explanation of nonlinear dynamical characteristics of roller type CPVA. Especially, it clarifies the importance of consideration of nonlinearity in the design of the roller type CPVA, both theoretically and experimentally. Furthermore, the difference between the pendulum type CPVA and roller type CPVA are discussed from the viewpoint of the effect of vibration suppression.

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