EXPERIMENTAL INVESTIGATION OF BEAM-TIP MASS AND PENDULUM SYSTEM UNDER RANDOM EXCITATION

2002 ◽  
Vol 16 (6) ◽  
pp. 1059-1072 ◽  
Author(s):  
I. CICEK ◽  
A. ERTAS
Author(s):  
A. Ertas ◽  
O. Cuvalci

Abstract The dynamic response of a beam-tip mass-pendulum system subjected to sinusoidal excitations is considered. The conditions under which resonant and nonresonant oscillations occur are investigated and discussed. The main objective of this study was to conduct a series of experiments to investigate the autoparametric interaction between the first two modes of the system. The use of a pendulum as a passive control device was experimentally evaluated.


Author(s):  
S. Garza ◽  
A. Ertas

Abstract An experimental investigation was performed to determine the dynamics of an inverted, impacting spherical pendulum with large deflection and vertical parametric forcing. The pendulum system was studied with nine different bob and two different base configurations, for twenty times the natural frequency at shaker powers of 0 to 125 mm-hz. It was found that sustained conical motions did not naturally occur. The spherical pendulum system was analyzed to determine under what conditions the onset of Type I and sustainable Type II responses occurred.


1996 ◽  
Vol 118 (4) ◽  
pp. 558-566 ◽  
Author(s):  
O. Cuvalci ◽  
A. Ertas

The dynamic response of a beam-tip mass-pendulum system subjected to a sinusoidal excitation is investigated. A simple pendulum mounted to a tip mass of a beam is used as a vibration absorber. The nonlinear equations of motion are developed to investigate the autoparametric interaction between the first two modes of the system. The nonlinear terms appear due to the curvature of the beam and the coupling effect between the beam and pendulum. Complete energy transfer between modes is shown to occur when the beam frequency is twice the pendulum frequency. Experimental results are compared with a theoretical solution obtained using numerical integration. The experimental results are in qualitative agreement with the theory.


1988 ◽  
Vol 55 (2) ◽  
pp. 467-473 ◽  
Author(s):  
R. A. Ibrahim ◽  
R. T. Heinrich

This paper presents an experimental investigation of the random parametric excitation of a dynamic system with nonlinear inertia. The experimental model is a rigid circular tank partially filled with an incompressible inviscid liquid. The random responses of the first antisymmetric and symmetric sloshing modes are considered for band-limited random excitations. These include the means, mean squares, and probability density functions of each sloshing mode. The response of the liquid-free surface is found to be a stationary process for test durations exceeding ten minutes. The time-history response records reveal four response characteristic regimes. Each regime takes place within a certain range of excitation spectral density level. An evidence of the jump phenomenon, which was predicted theoretically by using the non-Gaussian closure scheme, is also reported. Comparisons with analytical results, derived by three different approaches, are given for the first antisymmetric sloshing mode.


2020 ◽  
Vol 313 ◽  
pp. 00044
Author(s):  
Cyril Fischer ◽  
Jiří Náprstek

The contribution regards a mathematical single-degree-of-freedom model of a slender structure vibrating in an air flow. Based on an experimental investigation, movement of such structures can be expressed by van der PolDuffing-type equations. Several particular configuration parameter settings for a white and non-white Gaussian random excitation together with deterministic harmonic forcing are considered and numerically analysed. The results support recently published analytic formulas.


1985 ◽  
Vol 107 (2) ◽  
pp. 220-225 ◽  
Author(s):  
J. C. S. Yang ◽  
C. H. Marks ◽  
J. Jiang ◽  
D. Chen ◽  
A. Elahi ◽  
...  

An experimental investigation has been carried out to verify the validity of the use of the random decrement technique to determine the damping coefficients for a circular cylinder oscillating in water. Data are reported for amplitudes ranging from 0.4 diameters to 0.8 diameters, for water speeds from zero to 0.192 m/s (0.63 ft/sec), and for frequencies ranging from 0.37 Hz to 1.4 Hz. Comparison with other data, which has been reported in the literature or obtained by the authors, shows that the random decrement method yields comparable damping coefficients to those obtained using the logarithmic decrement technique for the range of variables in this experiment.


1989 ◽  
Vol 6 (2-4) ◽  
pp. 161-176 ◽  
Author(s):  
Raouf A. Ibrahim ◽  
Michael Evans ◽  
Yong-Joong Yoon

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