Experimental Verification of the Importance of The Nonlinear Curvature in the Response of a Cantilever Beam

1996 ◽  
Vol 118 (1) ◽  
pp. 21-27 ◽  
Author(s):  
T. J. Anderson ◽  
A. H. Nayfeh ◽  
B. Balachandran
Keyword(s):  
Analytical Model ◽  
Cantilever Beam ◽  
Theoretical Investigation ◽  
Experimental Verification ◽  
Dominant Role ◽  
Experimental Results ◽  
Parametrically Excited ◽  
Second Mode ◽  
Quadratic Damping ◽  
Theoretical Results

An experimental and theoretical investigation into the first- and second-mode responses of a parametrically excited slender cantilever beam is presented. Inclusion of quadratic damping in the analytical model significantly improves the agreement between the experimental and theoretical results. In addition, the experimental results verify that the often ignored nonlinear curvature terms play a dominant role in the response of the first mode and that the nonlinear inertia terms play a dominant role in the response of the second mode.

Nonlinear Dynamics of a Transversely Excited Flexible Cantilever Beam

1995 ◽  
Author(s):  
Mahmood Tabaddor ◽  
Ali H. Nayfeh
Keyword(s):  
Nonlinear Dynamics ◽  
Natural Frequency ◽  
Cantilever Beam ◽  
Experimental Results ◽  
Modal Interactions ◽  
Frequency Sweep ◽  
Second Mode ◽  
Fourth Mode

Abstract Some experimental results concerning the nonlinear dynamics of a transversely excited beam are presented. The excitation is harmonic. A frequency sweep around the fourth natural frequency of the beam reveals some interesting modal interactions. The first phenomenon is the transfer of energy from the fourth mode, approximately 33.10 Hz, to the first mode, approximately 0.70 Hz. This interaction involves modulation of the amplitude and phase of the fourth mode. The second interaction involves the participation of the fourth mode and the second mode, approximately 5.80 Hz. The mechanism by which the second mode is activated as yet remains unidentified.

scholarly journals Effects of Variations in Nonlinear Damping Coefficients on the Parametric Vibration of a Cantilever Beam with a Lumped Mass

2008 ◽  
Vol 2008 ◽  
pp. 1-19 ◽  
Author(s):  
Demian G. Silva ◽  
Paulo S. Varoto
Keyword(s):  
Energy Dissipation ◽  
Dynamic Response ◽  
Cantilever Beam ◽  
Drag Force ◽  
Perturbation Technique ◽  
Experimental Results ◽  
Flexible Structure ◽  
Lumped Mass ◽  
Force Coefficient ◽  
Quadratic Damping

Uncertainties in damping estimates can significantly affect the dynamic response of a given flexible structure. A common practice in linear structural dynamics is to consider a linear viscous damping model as the major energy dissipation mechanism. However, it is well known that different forms of energy dissipation can affect the structure's dynamic response. The major goal of this paper is to address the effects of the turbulent frictional damping force, also known as drag force on the dynamic behavior of a typical flexible structure composed of a slender cantilever beam carrying a lumped-mass on the tip. First, the system's analytical equation is obtained and solved by employing a perturbation technique. The solution process considers variations of the drag force coefficient and its effects on the system's response. Then, experimental results are presented to demonstrate the effects of the nonlinear quadratic damping due to the turbulent frictional force on the system's dynamic response. In particular, the effects of the quadratic damping on the frequency-response and amplitude-response curves are investigated. Numerically simulated as well as experimental results indicate that variations on the drag force coefficient significantly alter the dynamics of the structure under investigation.

An Experimental Verification of the Hemispherical Cup Puckering Problem

1989 ◽  
Vol 111 (3) ◽  
pp. 248-254 ◽  
Author(s):  
M. Donoghue ◽  
R. Stevenson ◽  
Y. J. Kwon ◽  
N. Triantafyllidis
Keyword(s):  
Experimental Study ◽  
Numerical Solution ◽  
Analytical Model ◽  
Experimental Verification ◽  
Critical Discussion ◽  
Solution Technique ◽  
Practical Reasons ◽  
Experimental Procedure ◽  
Theoretical Results

In this work is presented an experimental study of the hemispherical cup puckering test. This investigation is motivated by some theoretical as well as by some practical reasons which are elaborated upon in the introduction. After a brief outline of the analytical model and the corresponding numerical solution technique, the presentation continues with a description of the experimental procedure. A comparison between the experimental and the theoretical results is given next followed by a critical discussion.

Bifurcation control for a parametrically excited cantilever beam by linear feedback

2012 ◽  
Vol 226 (8) ◽  
pp. 1987-1999 ◽  
Author(s):  
Hiroshi Yabuno ◽  
Masahiko Hasegawa ◽  
Manami Ohkuma
Keyword(s):  
Cantilever Beam ◽  
Control Method ◽  
Dominant Role ◽  
Excitation Frequency ◽  
Excitation Amplitude ◽  
Bifurcation Control ◽  
Linear Feedback ◽  
Parametrically Excited ◽  
Saddle Node ◽  
Transcritical Bifurcations

In this article, we propose a bifurcation control method for a parametrically excited cantilever beam by linear feedback. Quadratic damping plays a dominant role in the nonlinear response of the parametrically excited cantilever beam, and two transcritical bifurcations can exist in the frequency–response curve. In the relatively high-amplitude excitation or in sweeping the excitation amplitude, there are two saddle-node bifurcations in addition to the transcritical bifurcations. The discontinuous bifurcation as a saddle-node bifurcation induces jumping phenomena in the sweeps of the excitation amplitude and the excitation frequency. In this article, we focus on the case of the excitation amplitude sweep and propose a control method to avoid the jumping phenomena by bifurcation control, i.e. by shifting the bifurcation set based on the linear feedback. The validity of the control method is experimentally confirmed using a simple apparatus.

scholarly journals Generalized analytical model based on harmonic coupling for hybrid plasmonic modes: comparison with numerical and experimental results

2015 ◽  
Vol 23 (21) ◽  
pp. 27376 ◽  
Author(s):  
Mitradeep Sarkar ◽  
Jean-François Bryche ◽  
Julien Moreau ◽  
Mondher Besbes ◽  
Grégory Barbillon ◽  
...  
Keyword(s):  
Analytical Model ◽  
Experimental Results ◽  
Model Based

A Comparison of Theoretical and Experimental Results From Spherical Shells With a Single Radially Attached Nozzle

1967 ◽  
Vol 89 (3) ◽  
pp. 333-338 ◽  
Author(s):  
F. J. Witt ◽  
R. C. Gwaltney ◽  
R. L. Maxwell ◽  
R. W. Holland
Keyword(s):  
Spherical Shell ◽  
Internal Pressure ◽  
Experimental Results ◽  
Strain Gages ◽  
Spherical Shells ◽  
Axial Thrust ◽  
Outside Diameter ◽  
Theoretical Results

A series of steel models having single nozzles radially and nonradially attached to a spherical shell is presently being examined by means of strain gages. Parameters being studied are nozzle dimensions, length of internal nozzle protrusions, and angles of attachment. The loads are internal pressure and axial thrust and moment loadings on the nozzle. This paper presents both experimental and theoretical results from six of the configurations having radially attached nozzles for which the sphere dimensions are equal and the outside diameter of the attached nozzle is constant. In some instances the nozzle protrudes through the vessel.

Convective Losses From Cavity Solar Receivers—Comparisons Between Analytical Predictions and Experimental Results

1983 ◽  
Vol 105 (1) ◽  
pp. 29-33 ◽  
Author(s):  
A. M. Clausing
Keyword(s):  
Experimental Data ◽  
Experimental Evidence ◽  
Analytical Model ◽  
Excellent Agreement ◽  
Experimental Results ◽  
Simple Analytical Model ◽  
Refined Model ◽  
Wall Area

Cavity solar receivers are generally believed to have higher thermal efficiencies than external receivers due to reduced losses. A simple analytical model was presented by the author which indicated that the ability to heat the air inside the cavity often controls the convective loss from cavity receivers. Thus, if the receiver contains a large amount of inactive hot wall area, it can experience a large convective loss. Excellent experimental data from a variety of cavity configurations and orientations have recently become available. These data provided a means of testing and refining the analytical model. In this manuscript, a brief description of the refined model is presented. Emphasis is placed on using available experimental evidence to substantiate the hypothesized mechanisms and assumptions. Detailed comparisons are given between analytical predictions and experimental results. Excellent agreement is obtained, and the important mechanisms are more clearly delineated.

Experimental Study on the Failure Criterion for Brittle Materials in Compression

2011 ◽  
Vol 320 ◽  
pp. 259-262
Author(s):  
Xu Ran ◽  
Zhe Ming Zhu ◽  
Hao Tang
Keyword(s):  
Thin Film ◽  
Experimental Study ◽  
Compressive Strength ◽  
Fracture Mechanics ◽  
Failure Criterion ◽  
Brittle Materials ◽  
Experimental Results ◽  
Experiment Study ◽  
Confining Stress ◽  
Theoretical Results

The mechanical behavior of multi-cracks under compression has become a very important project in the field of fracture mechanics and rock mechanics. In this paper, based on the previous theoretical results of the failure criterion for brittle materials under compression, experiment study is implemented. The specimens are square plates and are made of cement, sand and water, and the cracks are made by using a very thin film (0.1 mm). The relations of material compressive strength versus crack spacing and the lateral confining stress are obtained from experimental results. The experimental results agree well with the failure criterion for brittle materials under compression, which indicates that the criterion is effective and applicable.

Unbalance Response of a Dual Rotor System: Theory and Experiment

1993 ◽  
Vol 115 (4) ◽  
pp. 427-435 ◽  
Author(s):  
K. Gupta ◽  
K. D. Gupta ◽  
K. Athre
Keyword(s):  
System Theory ◽  
Transfer Matrix ◽  
Mode Shape ◽  
Reasonable Agreement ◽  
Complex Variables ◽  
Rotor System ◽  
Experimental Results ◽  
Unbalance Response ◽  
Theoretical Results ◽  
Theory And Experiment

A dual rotor rig is developed and is briefly discussed. The rig is capable of simulating dynamically the two spool aeroengine, though it does not physically resemble the actual aeroengine configuration. Critical speeds, mode shape, and unbalance response are determined experimentally. An extended transfer matrix procedure in complex variables is developed for obtaining unbalance response of dual rotor system. Experimental results obtained are compared with theoretical results and are found to be in reasonable agreement.

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