Experimental investigation of resonantly forced oscillations of a two-degree-of-freedom structure

This paper shows how the Lighthill-Poincaré perturbation technique may be used to determine the transient response of ‘lightly coupled’ non-linear multi-degree-of-freedom oscillatory systems subject to arbitrary forcing functions. The results in general are complex but simplify in many important cases. A comparison is made between the analytical results and results obtained by a numerical integration of the equations on a computer. Good agreement is noted. The method fails under conditions of ‘internal resonance’ of the system.

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An experimental investigation of one- and two-degree of freedom VIV of cylinders

Acta Mechanica Sinica ◽

10.1007/s10409-013-0014-5 ◽

2013 ◽

Vol 29 (2) ◽

pp. 284-293 ◽

Cited By ~ 10

Author(s):

Zhuang Kang ◽

Lu-Sheng Jia

Keyword(s):

Experimental Investigation ◽

Degree Of Freedom ◽

Two Degree Of Freedom

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Forced Nonlinear Oscillations of an Autoparametric System—Part 2: Chaotic Responses

Journal of Applied Mechanics ◽

10.1115/1.3167107 ◽

1983 ◽

Vol 50 (3) ◽

pp. 663-668 ◽

Cited By ~ 47

Author(s):

H. Hatwal ◽

A. K. Mallik ◽

A. Ghosh

Keyword(s):

Statistical Analysis ◽

Nonlinear Oscillations ◽

Degree Of Freedom ◽

Experimental Results ◽

Forced Oscillations ◽

Mean Square ◽

Chaotic Oscillations ◽

System Part ◽

The Mean ◽

Two Degree Of Freedom

Chaotic oscillations arising in forced oscillations of a two degree-of-freedom autoparametric system are studied. Statistical analysis of the numerically integrated nonperiodic responses is shown to be a meaningful description of the mean square values and the frequency contents of the responses. Some qualitative experimental results are presented to substantiate the necessity of performing the statistical analysis of the responses even though the system and the input are deterministic.

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Experimental Determination of the Complete Dynamical Properties of a Two-Degree-Of-Freedom Model Having Nearly Coincident Natural Frequencies

Journal of Mechanical Engineering Science ◽

10.1243/jmes_jour_1967_009_061_02 ◽

1967 ◽

Vol 9 (5) ◽

pp. 402-413 ◽

Cited By ~ 6

Author(s):

R. W. Traill-Nash ◽

G. Long ◽

C. M. Bailey

Keyword(s):

Experimental Investigation ◽

Experimental Determination ◽

Natural Frequencies ◽

Degree Of Freedom ◽

Influence Coefficients ◽

Stiffness Properties ◽

Modes Of Vibration ◽

Dynamical Properties ◽

Two Degree Of Freedom

Existing techniques of resonance testing have shown a marked inability to find the principal modes, natural frequencies and levels of damping in a structure which possesses two or more close natural frequencies (1)§. This paper describes an experimental investigation on a two-degree-of-freedom model of a technique which makes use of dynamical influence coefficients (or receptances) measured at a number of stations on the structure (2) (3) (4) (5). The measured coefficients are used to calculate natural frequencies and modes of vibration, and the mass, damping and stiffness properties of the system. Several model configurations having different natural frequency separations were tested and no special difficulty resulted when natural frequencies were close or even coincident.

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