東華大學圖書館 |

Language: English

Help

回圖書館首頁

手機版館藏查詢

Back to Search results for [ null ]

Switch To: Labeled | MARC Mode | ISBD

Passive broadband targeted energy tr...

Lee, Young S.

Linked to FindBook

Google Book

Amazon

博客來

Passive broadband targeted energy transfers and control of self-excited vibrations.

Record Type:	Language materials, printed : Monograph/item
Title/Author:	Passive broadband targeted energy transfers and control of self-excited vibrations./
Author:	Lee, Young S.
Description:	328 p.
Notes:	Advisers: Lawrence A. Bergman; Alexander F. Vakakis.
Contained By:	Dissertation Abstracts International67-11B.
Subject:	Applied Mechanics. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3242915
ISBN:	9780542989421

Passive broadband targeted energy transfers and control of self-excited vibrations.
Lee, Young S.

Passive broadband targeted energy transfers and control of self-excited vibrations. - 328 p.

Advisers: Lawrence A. Bergman; Alexander F. Vakakis.

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2006.

In order to improve robustness of instability suppression, several types of multi-DOF NES configurations are introduced.

ISBN: 9780542989421Subjects--Topical Terms:

1018410
Applied Mechanics.

Passive broadband targeted energy transfers and control of self-excited vibrations.
LDR:05984nam 2200385 a 45 001 973205
005 20110928
008 110928s2006 eng d
020 $a 9780542989421
035 $a (UMI)AAI3242915
035 $a AAI3242915
040 $a UMI $c UMI
100 1 $a Lee, Young S. $3 1297161
245 1 0 $a Passive broadband targeted energy transfers and control of self-excited vibrations.
300 $a 328 p.
500 $a Advisers: Lawrence A. Bergman; Alexander F. Vakakis.
500 $a Source: Dissertation Abstracts International, Volume: 67-11, Section: B, page: 6699.
502 $a Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2006.
520 $a In order to improve robustness of instability suppression, several types of multi-DOF NES configurations are introduced.
520 $a Then, triggering mechanisms of aeroelastic instability is investigated for a two-DOF rigid wing model in subsonic flow with cubic nonlinear stiffnesses at the support.
520 $a This work consists of the three main parts---Nonlinear energy pumping (that is, passive broadband targeted energy transfers---TETs), and its applications to theoretical and experimental suppression of aeroelastic instabilities.
520 $a In the first part, nonlinear energy pumping (or TETs) in coupled oscillators is studied. The system is composed of a primary linear subsystem coupled through an essentially nonlinear stiffness and a linear viscous damper to an additional mass (which is called, as a whole, a nonlinear energy sink---NES). By considering the linear damping as a perturbation to the system, periodic solutions of the underlying Hamiltonian system are formulated by means of the non-smooth temporal transformation and solved numerically by a shooting method. The special periodic orbits, which are corresponding to the impulsive initial conditions for the primary subsystem, bear their importance as baits for initiating localized transfers of a significant portion of energy to the NES.
520 $a The second part theoretically deals with suppression of limit cycle oscillations (LCOs) in self-excited systems by means of passive energy localizations. As a pilot scheme, suppression or even complete elimination of the LCO in a van der Pol (VDP) oscillator coupled with two types of NESS---grounded and ungrounded---is studied. Computational parametric study proves the efficacy of LCO elimination by means of passive nonlinear energy pumping from the VDP oscillator to appropriately designed NESs. The numerical study of the transient dynamics of the system showed that the dynamical mechanism for LCO suppression is a series of 1:1 and 1:3 transient resonance captures, with the damped transient dynamics following closely corresponding resonant manifolds of the underlying Hamiltonian system. It is through the TRCs that energy gets transferred from the VDP oscillator to the NES, thus causing LCO suppression. By performing an additional bifurcation analysis of the steady state responses through a numerical continuation of equilibria and periodic solutions, the parameter dependence and bifurcations of the steady-state solutions are examined. It is also proved that a Hopf bifurcation is the global dynamical mechanism for generation and elimination of the LCOs in the configurations considered. The bifurcation analysis revealed that it is possible to design grounded or ungrounded NESs that robustly and completely eliminate the LCO instability of the system. This should be possible when the system parameters are chosen such that a subcritical Hopf bifurcation occurs, thus assuring the existence of a unique global trivial attractor of the dynamics in the parameter ranges of interest.
520 $a Based on the observation of the instability triggering, a single-degree-of-freedom (SDOF) NES is applied to the wing model. The NES is attached at an offset from the elastic axis for its additional interaction with the pitch mode, as well as being parallel with the heave mode, primarily to hinder initial triggering of the heave mode by the flow. It is shown that it is feasible to partially or even completely suppress aeroelastic instabilities of the wing by passively transferring vibration energy from the wing to the NES in a one-way irreversible fashion. Moreover, this aeroelastic instability suppression is performed by partially or completely eliminating the triggering mechanists for aeroelastic suppression. Through numerical parametric studies three main mechanisms for suppressing aeroelastic instability are identified: (i) Recurring burst-out and suppression; (ii) intermediate suppression; (iii) complete elimination of instability. In general, the relative occurrence of one of the two limit point cycle (LPC) bifurcations with respect to the Hopf bifurcation decides whether or not the suppression mechanisms are robust.
520 $a In the last part, experimental suppression of aeroelastic instability by means of targeted energy transfers is investigated. In order to gain insights into the experiments, theoretical triggering mechanism of the aeroelastic instability in the nonlinear aeroelastic test apparatus (NATA) in a low-speed wind tunnel at Texas A&M University is studied.
520 $a Finally, experimental results are presented in connection to the theoretical investigation, and all the predictions on the instability suppression mechanisms are demonstrated experimentally. It is also revealed that the dry friction affects only the robustness of an instability suppression by changing the unstable trivial equilibrium into an equilibrium set. (Abstract shortened by UMI.)
590 $a School code: 0090.
650 4 $a Applied Mechanics. $3 1018410
650 4 $a Engineering, Aerospace. $3 1018395
650 4 $a Engineering, Mechanical. $3 783786
690 $a 0346
690 $a 0538
690 $a 0548
710 2 0 $a University of Illinois at Urbana-Champaign. $3 626646
773 0 $t Dissertation Abstracts International $g 67-11B.
790 $a 0090
790 1 0 $a Bergman, Lawrence A., $e advisor
790 1 0 $a Vakakis, Alexander F., $e advisor
791 $a Ph.D.
792 $a 2006
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3242915