The Experts below are selected from a list of 6039 Experts worldwide ranked by ideXlab platform
Andrew Y. T. Leung - One of the best experts on this subject based on the ideXlab platform.
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The Jump Phenomenon effect on the sound absorption of a nonlinear panel absorber and sound transmission loss of a nonlinear panel backed by a cavity
Nonlinear Dynamics, 2011Co-Authors: Yiu-yin Lee, Andrew Y. T. LeungAbstract:Theoretical analysis of the nonlinear vibration effects on the sound absorption of a panel absorber and sound transmission loss of a panel backed by a rectangular cavity is herein presented. The harmonic balance method is employed to derive a structural acoustic formulation from two-coupled partial differential equations representing the nonlinear structural forced vibration and induced acoustic pressure; one is the well-known von Karman’s plate equation and the other is the homogeneous wave equation. This method has been used in a previous study of nonlinear structural vibration, in which its results agreed well with the elliptic solution. To date, very few classical solutions for this nonlinear structural-acoustic problem have been developed, although there are many for nonlinear plate or linear structural-acoustic problems. Thus, for verification purposes, an approach based on the numerical integration method is also developed to solve the nonlinear structural-acoustic problem. The solutions obtained with the two methods agree well with each other. In the parametric study, the panel displacement amplitude converges with increases in the number of harmonic terms and acoustic and structural modes. The effects of excitation level, cavity depth, boundary condition, and damping factor are also examined. The main findings include the following: (1) the well-known “Jump Phenomenon” in nonlinear vibration is seen in the sound absorption and transmission loss curves; (2) the absorption peak and transmission loss dip due to the nonlinear resonance are significantly wider than those in the linear case because of the wider resonant bandwidth; and (3) nonlinear vibration has the positive effect of widening the absorption bandwidth, but it also degrades the transmission loss at the resonant frequency.
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The Jump Phenomenon effect on the sound absorption of a nonlinear panel absorber and sound transmission loss of a nonlinear panel backed by a cavity
Nonlinear Dynamics, 2011Co-Authors: Yiu-yin Lee, Andrew Y. T. LeungAbstract:Theoretical analysis of the nonlinear vibration effects on the sound absorption of a panel absorber and sound transmission loss of a panel backed by a rectangular cavity is herein presented. The harmonic balance method is employed to derive a structural acoustic formulation from two-coupled partial differential equations representing the nonlinear structural forced vibration and induced acoustic pressure; one is the well-known von Karman's plate equation and the other is the homogeneous wave equation. This method has been used in a previous study of nonlinear structural vibration, in which its results agreed well with the elliptic solution. To date, very few classical solutions for this nonlinear structural-acoustic problem have been developed, although there are many for nonlinear plate or linear structural-acoustic problems. Thus, for verification purposes, an approach based on the numerical integration method is also developed to solve the nonlinear structural-acoustic problem. The solutions obtained with the two methods agree well with each other. In the parametric study, the panel displacement amplitude converges with increases in the number of harmonic terms and acoustic and structural modes. The effects of excitation level, cavity depth, boundary condition, and damping factor are also examined. The main findings include the following: (1) the well-known "Jump Phenomenon" in nonlinear vibration is seen in the sound absorption and transmission loss curves; (2) the absorption peak and transmission loss dip due to the nonlinear resonance are significantly wider than those in the linear case because of the wider resonant bandwidth; and (3) nonlinear vibration has the positive effect of widening the absorption bandwidth, but it also degrades the transmission loss at the resonant frequency. © 2011 Springer Science+Business Media B.V.link_to_subscribed_fulltex
B. Ravindra - One of the best experts on this subject based on the ideXlab platform.
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Sweep Tests on Vibrating Systems with Power-Law Damping
Nonlinear Dynamics, 1999Co-Authors: B. Ravindra, P. Hagedorn, Asok K. MallikAbstract:The non-stationary response in vibrating systems with power-law damping, subjected to sweep tests is considered. Using the method of averaging, it is shown that the bifurcation delay persists in all forms of power-law damping, viz., Coulomb, orifice and cubic damping models. Experimental investigations on a ‘soft’ type of isolator confirm the existence of delay in the Jump Phenomenon. These results also indicate that the softening nature of non-linearity can be profitably employed in the design of isolators and vehicle suspensions.
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Sweep Tests on Vibrating Systems with Power-Law Damping
Nonlinear Dynamics, 1999Co-Authors: B. Ravindra, P. Hagedorn, A. K. MallikAbstract:The non-stationary response in vibrating systems with power-law damping, subjected to sweep tests is considered. Using the method of averaging, it is shown that the bifurcation delay persists in all forms of power-law damping, viz., Coulomb, orifice and cubic damping models. Experimental investigations on a ‘soft’ type of isolator confirm the existence of delay in the Jump Phenomenon. These results also indicate that the softening nature of non-linearity can be profitably employed in the design of isolators and vehicle suspensions.
L. J. Mclean - One of the best experts on this subject based on the ideXlab platform.
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Stability and Bifurcation of Unbalanced Response of a Squeeze Film Damped Flexible Rotor
Journal of Tribology, 1994Co-Authors: J. Y. Zhao, I. W. Linnett, L. J. McleanAbstract:The stability and bifurcation of the unbalance response of a squeeze film damper-mounted flexible rotor are investigated based on the assumption of an incompressible lubricant together with the short bearing approximation and the “π” film cavitation model. The unbalanced rotor response is determined by the trigonometric collocation method and the stability of these solutions is then investigated using the Floquet transition matrix method. Numerical examples are given for both concentric and eccentric damper operations. Jump Phenomenon, subharmonic, and quasi-periodic vibrations are predicted for a range of bearing and unbalance parameters. The predicted Jump Phenomenon, subharmonic and quasi-periodic vibrations are further examined by using a numerical integration scheme to predict damper trajectories, calculate Poincare maps and power spectra. It is concluded that the introduction of unpressurized squeeze film dampers may promote undesirable nonsynchronous vibrations.
Yiu-yin Lee - One of the best experts on this subject based on the ideXlab platform.
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The Jump Phenomenon effect on the sound absorption of a nonlinear panel absorber and sound transmission loss of a nonlinear panel backed by a cavity
Nonlinear Dynamics, 2011Co-Authors: Yiu-yin Lee, Andrew Y. T. LeungAbstract:Theoretical analysis of the nonlinear vibration effects on the sound absorption of a panel absorber and sound transmission loss of a panel backed by a rectangular cavity is herein presented. The harmonic balance method is employed to derive a structural acoustic formulation from two-coupled partial differential equations representing the nonlinear structural forced vibration and induced acoustic pressure; one is the well-known von Karman’s plate equation and the other is the homogeneous wave equation. This method has been used in a previous study of nonlinear structural vibration, in which its results agreed well with the elliptic solution. To date, very few classical solutions for this nonlinear structural-acoustic problem have been developed, although there are many for nonlinear plate or linear structural-acoustic problems. Thus, for verification purposes, an approach based on the numerical integration method is also developed to solve the nonlinear structural-acoustic problem. The solutions obtained with the two methods agree well with each other. In the parametric study, the panel displacement amplitude converges with increases in the number of harmonic terms and acoustic and structural modes. The effects of excitation level, cavity depth, boundary condition, and damping factor are also examined. The main findings include the following: (1) the well-known “Jump Phenomenon” in nonlinear vibration is seen in the sound absorption and transmission loss curves; (2) the absorption peak and transmission loss dip due to the nonlinear resonance are significantly wider than those in the linear case because of the wider resonant bandwidth; and (3) nonlinear vibration has the positive effect of widening the absorption bandwidth, but it also degrades the transmission loss at the resonant frequency.
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The Jump Phenomenon effect on the sound absorption of a nonlinear panel absorber and sound transmission loss of a nonlinear panel backed by a cavity
Nonlinear Dynamics, 2011Co-Authors: Yiu-yin Lee, Andrew Y. T. LeungAbstract:Theoretical analysis of the nonlinear vibration effects on the sound absorption of a panel absorber and sound transmission loss of a panel backed by a rectangular cavity is herein presented. The harmonic balance method is employed to derive a structural acoustic formulation from two-coupled partial differential equations representing the nonlinear structural forced vibration and induced acoustic pressure; one is the well-known von Karman's plate equation and the other is the homogeneous wave equation. This method has been used in a previous study of nonlinear structural vibration, in which its results agreed well with the elliptic solution. To date, very few classical solutions for this nonlinear structural-acoustic problem have been developed, although there are many for nonlinear plate or linear structural-acoustic problems. Thus, for verification purposes, an approach based on the numerical integration method is also developed to solve the nonlinear structural-acoustic problem. The solutions obtained with the two methods agree well with each other. In the parametric study, the panel displacement amplitude converges with increases in the number of harmonic terms and acoustic and structural modes. The effects of excitation level, cavity depth, boundary condition, and damping factor are also examined. The main findings include the following: (1) the well-known "Jump Phenomenon" in nonlinear vibration is seen in the sound absorption and transmission loss curves; (2) the absorption peak and transmission loss dip due to the nonlinear resonance are significantly wider than those in the linear case because of the wider resonant bandwidth; and (3) nonlinear vibration has the positive effect of widening the absorption bandwidth, but it also degrades the transmission loss at the resonant frequency. © 2011 Springer Science+Business Media B.V.link_to_subscribed_fulltex
Asok K. Mallik - One of the best experts on this subject based on the ideXlab platform.
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Sweep Tests on Vibrating Systems with Power-Law Damping
Nonlinear Dynamics, 1999Co-Authors: B. Ravindra, P. Hagedorn, Asok K. MallikAbstract:The non-stationary response in vibrating systems with power-law damping, subjected to sweep tests is considered. Using the method of averaging, it is shown that the bifurcation delay persists in all forms of power-law damping, viz., Coulomb, orifice and cubic damping models. Experimental investigations on a ‘soft’ type of isolator confirm the existence of delay in the Jump Phenomenon. These results also indicate that the softening nature of non-linearity can be profitably employed in the design of isolators and vehicle suspensions.
