A Theoretical and Experimental Investigation of the Dynamic Response of a Slider-Crank Mechanism With Radial Clearance in the Gudgeon-Pin Joint

1990 ◽  
Vol 112 (2) ◽  
pp. 183-189 ◽  
Author(s):  
K. Soong ◽  
B. S. Thompson
Keyword(s):  
Experimental Investigation ◽  
Dynamic Response ◽  
Dynamical Behavior ◽  
Kinematic Chain ◽  
Analytical Investigation ◽  
Rigid Bodies ◽  
Radial Clearance ◽  
Revolute Joints ◽  
Theoretical Predictions ◽  
Crank Mechanism

A comprehensive analytical investigation of the dynamic response of a general planar kinematic chain comprising an assemblage of articulating interconnected rigid-bodies with bearing clearances in the revolute joints is presented. The equations governing the dynamical behavior of this general mechanical system are established by incorporating a four-mode model of the phenomenological behavior of the principal elements of each revolute joint into the generalized form of Lagrange’s equations. The proposed methodology is then employed to predict the dynamic behavior of a planar slider-crank mechanism with radial clearance in the gudgeon-pin joint prior to comparing these theoretical predictions with the corresponding response-data from a complementary experimental investigation.

An Experimental Investigation of the Dynamic Response of a Mechanical System With Bearing Clearance

1987 ◽  
Author(s):  
K. Soong ◽  
B. S. Thompson
Keyword(s):  
Experimental Investigation ◽  
Dynamic Response ◽  
Computational Models ◽  
Design Guidelines ◽  
Rigid Bodies ◽  
Radial Clearance ◽  
Experimental Investigations ◽  
Similar System ◽  
Response Data ◽  
Bearing Clearance

Abstract Numerous publications have been devoted to the development of analytical and computational models for predicting the dynamic response of mechanical systems comprising assemblages of rigid-bodies with clearance at the joints. However, there is a dearth of experimental investigations in this area which focus on furnishing complementary response data, consequently the predictive capabilities of these theoretical models are largely unknown. The experimental investigation presented herein, is motivated by this observation and is directed towards partially filling this significant void in the literature. In order to accomplish this goal, a comprehensive experimental study was undertaken of a slider-crank mechanism in which the radial clearance at the gudgeon-pin bearing was carefully controlled. Response data at different operating speeds are presented, along with an investigation of the bearing characteristics from which the coefficient of restitution, which features in many of the proposed mathematical models, was evaluated. Finally, design guidelines are distilled from the experimental data to relate the response of the system to the response of a similar system without bearing clearance.

scholarly journals Rotor Instability Induced by Radial Clearance in Ball Bearing Supports

1993 ◽  
Author(s):  
Yao-Qun Lin
Keyword(s):  
Experimental Investigation ◽  
Internal Friction ◽  
Natural Frequency ◽  
Computer Simulations ◽  
Ball Bearing ◽  
Rotor Dynamics ◽  
Experimental Results ◽  
Radial Clearance ◽  
Speed Range ◽  
Theoretical Predictions

In rotor dynamics, the rotor nonsynchronous natural frequency vibration, or rotor instability, has been mainly ascribed to two mechanisms, i.e., internal friction effects and fluid actions. It is shown, however, in this paper that the radial clearance in ball bearing supports can also induce rotor instability through an internal-impacts mechanism. The behavior of the rotor with radial clearance in its ball bearing supports is simulated numerically. The computer simulations show that there is a speed range in which the rotor will vibrate at both the synchronous frequency and the natural frequency. Below or above this speed range, the rotor has only the synchronous response and its harmonics. An experimental investigation was conducted to verify this analysis. The experimental results agree well with the theoretical predictions.

An Experimental Investigation of Auditors' Liability: Implications for Social Welfare and Exploration of Deviations from Theoretical Predictions

2000 ◽  
Vol 75 (4) ◽  
pp. 429-451 ◽  
Author(s):  
Ronald R. King ◽  
Rachel Schwartz
Keyword(s):  
Experimental Investigation ◽  
Social Welfare ◽  
Strict Liability ◽  
Liability Rule ◽  
Optimal Response ◽  
Legal Regimes ◽  
Theoretical Predictions ◽  
Best Responses

This paper reports the results of an experiment designed to investigate how legal regimes affect social welfare. We investigate four legal regimes, each consisting of a liability rule (strict or negligence) and a damage measure (out-of-pocket or independent-of-investment). The results of the experiment are for the most part consistent with the qualitative predictions of Schwartz's (1997) model; however, subjects' actual choices deviate from the point predictions of the model. We explore whether these deviations arise because: (1) subjects form faulty anticipations of their counterparts' actions and/or (2) subjects do not choose the optimal responses given their anticipations. We find that subjects behave differently under the four regimes in terms of anticipation errors and departures from best responses. For example, subjects playing the role of auditors anticipate investments most accurately under the regime with strict liability combined with out-of-pocket damages, but are least likely to choose the optimal response given their anticipations. This finding implies that noneconomic factors likely play a role in determining subjects' choices.

Dynamic Behavior of Aircraft Wings Modeled as Doubly-Tapered Composite Thin-Walled Beams

1999 ◽  
Author(s):  
Sungsoo Na ◽  
Liviu Librescu
Keyword(s):  
Composite Materials ◽  
Free Vibration ◽  
Dynamic Response ◽  
Dynamic Behavior ◽  
Transverse Shear ◽  
Dynamical Behavior ◽  
Time Dependent ◽  
Aircraft Wings ◽  
Helicopter Blades ◽  
Thin Walled

Abstract A study of the dynamical behavior of aircraft wings modeled as doubly-tapered thin-walled beams, made from advanced anisotropic composite materials, and incorporating a number of non-classical effects such as transverse shear, and warping inhibition is presented. The supplied numerical results illustrate the effects played by the taper ratio, anisotropy of constituent materials, transverse shear flexibility, and warping inhibition on free vibration and dynamic response to time-dependent external excitations. Although considered for aircraft wings, this analysis and results can be also applied to a large number of structures such as helicopter blades, robotic manipulator arms, space booms, tall cantilever chimneys, etc.

scholarly journals The Dynamic Response of Tuned Impact Absorbers for Rotating Flexible Structures

2005 ◽  
Vol 1 (1) ◽  
pp. 13-24 ◽  
Author(s):  
Steven W. Shaw ◽  
Christophe Pierre
Keyword(s):  
Dynamic Response ◽  
Flexible Structures ◽  
Experimental Studies ◽  
Analytical Investigation ◽  
Design Parameters ◽  
System Response ◽  
Rotor Speed ◽  
Flexible System ◽  
Restoring Forces ◽  
And Performance

This paper describes an analytical investigation of the dynamic response and performance of impact vibration absorbers fitted to flexible structures that are attached to a rotating hub. This work was motivated by experimental studies at NASA, which demonstrated the effectiveness of these types of absorbers for reducing resonant transverse vibrations in periodically excited rotating plates. Here we show how an idealized model can be used to describe the essential dynamics of these systems, and used to predict absorber performance. The absorbers use centrifugally induced restoring forces so that their nonimpacting dynamics are tuned to a given order of rotation, whereas their large amplitude dynamics involve impacts with the primary flexible system. The linearized, nonimpacting dynamics are first explored in detail, and it is shown that the response of the system has some rather unique features as the hub rotor speed is varied. A class of symmetric impacting motions is also analyzed and used to predict the effectiveness of the absorber when operating in its impacting mode. It is observed that two different types of grazing bifurcations take place as the rotor speed is varied through resonance, and their influence on absorber performance is described. The analytical results for the symmetric impacting motions are also used to generate curves that show how important absorber design parameters—including mass, coefficient of restitution, and tuning—affect the system response. These results provide a method for quickly evaluating and comparing proposed absorber designs.

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