Response of Two-Degree-of-Freedom Rotating Machinery System With Quadratic Nonlinearity

1990 ◽  
Vol 112 (2) ◽  
pp. 103-113 ◽  
Author(s):  
A. Ertas ◽  
G. Anlas
Keyword(s):  
Internal Resonance ◽  
Multiple Scales ◽  
Nonlinear Oscillations ◽  
Center Of Mass ◽  
Degree Of Freedom ◽  
Saturation Phenomenon ◽  
Nonlinear Springs ◽  
Rotating Machine ◽  
Two Degree Of Freedom ◽  
Machinery System

A two-degree-of-freedom model of a rotating machine with nonlinear springs of quadratic type is studied. The multiple scales method is used to investigate the nonlinear oscillations of the forced system where the forcing is due to the eccentricity e of the rotor about its center of mass. The behavior of the system for the primary resonances Ω = ω1, Ω = ω2, and internal resonance ω2 = 2ω1 is analyzed. Other features, such as amplitude jump and saturation phenomenon, have been observed. The amplitudes versus detuning parameters for both cases are plotted. The critical values of mass ratios and spring ratios for the presence of an internal resonance are studied and interpreted for this particular application.

Analytical Investigation of Vibration Attenuation With a Nonlinear Tuned Mass Damper

2015 ◽  
Author(s):  
Andrew J. Dick ◽  
Aaron Atzil ◽  
Satish Nagarajaiah
Keyword(s):  
Primary Structure ◽  
Multiple Scales ◽  
Tuned Mass Damper ◽  
Analytical Investigation ◽  
Degree Of Freedom ◽  
Approximate Analytical Solutions ◽  
Vibration Attenuation ◽  
Mass Damper ◽  
Two Degree Of Freedom ◽  
Nonlinear Tuned Mass Damper

Vibration attenuation devices are used to reduce the vibrations of various mechanical systems and structures. In this work, an analytical method is proposed to provide the means to investigate the influence of system parameters on the dynamic response of a system. The method of multiple scales is used to calculate an approximate broadband solution for a two degree-of-freedom system consisting of a linear primary structure and a nonlinear tuned mass damper. The model is decoupled, approximate analytical solutions are calculated, and then they are combined to produce the desired frequency-response information. The approach is initially applied to a linear two degree-of-freedom system in order to verify its performance. The approach is then applied to the nonlinear system in order to study how varying the values of parameters associated with the nonlinear absorber affect its ability to attenuate the response of the primary structure.

Forced Oscillations of Non-Linear Two-Degree-of-Freedom Systems

1966 ◽  
Vol 8 (3) ◽  
pp. 252-258 ◽  
Author(s):  
G. N. Bycroft
Keyword(s):  
Numerical Integration ◽  
Transient Response ◽  
Internal Resonance ◽  
Perturbation Technique ◽  
Degree Of Freedom ◽  
Forced Oscillations ◽  
Oscillatory Systems ◽  
Non Linear ◽  
Two Degree Of Freedom ◽  
Good Agreement

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.

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

1983 ◽  
Vol 50 (3) ◽  
pp. 663-668 ◽  
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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