Enhanced passive targeted energy transfer in strongly nonlinear mechanical oscillators

Targeted energy transfer (TET) refers to the spatial transfer of energy between a primary structure of interest and isolated oscillators called the energy sink (ES). In this work, the primary structure of interest is a slender beam modeled by the Euler-Bernoulli theory, and the ES is a single-degree-of-freedom oscillator with either linear or cubic nonlinear stiffness property. The objective of this study is to characterize the TET and the effectiveness of ES under impact and periodic excitations. By using the scientific computation package, MATLAB, numerical simulations are carried out based on excitations of various strength and locations. Both time and frequency domain characterizations are used. For the impact excitation, the ES with the cubic nonlinear stiffness property is more superior to the linear oscillator in that larger percentage of the impact energy can be dissipated there. The main energy transfer was found to be due to a 3- to-1 frequency coupling between the first bending mode and the ES. For the periodic excitation, however, both linear and nonlinear ES exhibit generally poorer performance than the case with the impact excitation. Future works should focus on the frequency-energy relationship of the periodic solution of the underlying Hamiltonian, as well as using finite element model to verify the simulation results.

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Targeted Energy Transfer through Discrete Breathers in Nonlinear Systems

Physical Review Letters ◽

10.1103/physrevlett.87.165501 ◽

2001 ◽

Vol 87 (16) ◽

Cited By ~ 116

Author(s):

G. Kopidakis ◽

S. Aubry ◽

G. P. Tsironis

Keyword(s):

Energy Transfer ◽

Nonlinear Systems ◽

Targeted Energy Transfer ◽

Discrete Breathers

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Mechanics of the human femoral adventitia including the high-pressure response

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00397.2001 ◽

2002 ◽

Vol 282 (6) ◽

pp. H2427-H2440 ◽

Cited By ~ 97

Author(s):

Christian A. J. Schulze-Bauer ◽

Peter Regitnig ◽

Gerhard A. Holzapfel

Keyword(s):

High Pressures ◽

Energy Functions ◽

Mean Values ◽

Mechanical Responses ◽

Strongly Nonlinear ◽

Pressure Load ◽

Nonlinear Mechanical ◽

Load Carrying

Adventitial mechanics were studied on the basis of adventitial tube tests and associated stress analyses utilizing a thin-walled model. Inflation tests of 11 nonstenotic human femoral arteries (79.3 ± 8.2 yr, means ± SD) were performed during autopsy. Adventitial tubes were separated anatomically and underwent cyclic, quasistatic extension-inflation tests using physiological pressures and high pressures up to 100 kPa. Associated circumferential and axial stretches were typically <20%, indicating “adventitiosclerosis.” Adventitias behaved nearly elastically for both loading domains, demonstrating high tensile strengths (>1 MPa). The anisotropic and strongly nonlinear mechanical responses were represented appropriately by two-dimensional Fung-type stored-energy functions. At physiological pressure (13.3 kPa), adventitias carry ∼25% of the pressure load in situ, whereas their circumferential and axial stresses were similar to the total wall stresses (∼50 kPa in both directions), supporting a “uniform stress hypothesis.” At higher pressures, they became the mechanically predominant layer, carrying >50% of the pressure load. These significant load-carrying capabilities depended strongly on circumferential and axial in-vessel prestretches (mean values: 0.95 and 1.08). On the basis of these results, the mechanical role of the adventitia at physiological and hypertensive states and during balloon angioplasty was characterized.

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Targeted Energy Transfer to a Rotary Nonlinear Energy Sink

Volume 5: 22nd International Conference on Design Theory and Methodology; Special Conference on Mechanical Vibration and Noise ◽

10.1115/detc2010-28840 ◽

2010 ◽

Cited By ~ 1

Author(s):

Sean A. Hubbard ◽

D. Michael McFarland ◽

Alexander F. Vakakis ◽

Lawrence A. Bergman

Keyword(s):

Finite Element ◽

Energy Transfer ◽

Finite Element Model ◽

Nonlinear Energy Sink ◽

Element Model ◽

Targeted Energy Transfer ◽

Discrete Equations ◽

Resonant Interactions ◽

Energy Sink ◽

Nonlinear Energy

We study computationally the passive, nonlinear targeted energy transfers induced by resonant interactions between a single-degree-of-freedom nonlinear energy sink and a uniform-plate model of a flexible, swept aircraft wing. We show that the nonlinear energy sink can be designed to quickly and efficiently absorb energy from one or more wing modes in a completely passive manner. Results indicate that it is feasible to use such a device to suppress or prevent aeroelastic instabilities like limit-cycle oscillations. The design of a compact nonlinear energy sink is introduced and the parameters of the device are examined. Simulations performed using a finite-element model of the wing coupled to discrete equations governing the energy sink indicate that targeted energy transfer is achievable, resulting, for example, in a rapid and significant reduction in the second bending mode response of the wing. Finally, the finite element model is used to simulate the effects of increased nonlinear energy sink stiffness, and to show the conditions under which the nonlinear energy sink will resonantly interact with higher-frequency wing modes.

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