Application of Targeted Energy Transfer (TET) Techniques to the Seismic Protection of a Small Scale Multistorey Eccentric Steel Structure

2011 ◽  
Author(s):  
Concetta Tripepi ◽  
Francesco Nucera ◽  
Lawrence A. Bergman ◽  
D. Michael McFarland ◽  
Alexander F. Vakakis
Keyword(s):  
Energy Transfer ◽  
Linear System ◽  
Steel Structure ◽  
Steel Structures ◽  
Nonlinear Energy Sink ◽  
Small Scale ◽  
Targeted Energy Transfer ◽  
Resonance Capture ◽  
System A ◽  
Transient Resonance

The aim of this work is to show that is possible to apply the Nonlinear Energy Sink (NES) concept to protect seismically excited eccentric steel structures through Targeted Energy Transfer (TET). We consider, as the primary (linear) system, a small-scale four-storey unsymmetrical-plan building, modeled as a twelve-degree-of-freedom-system, with floors sufficiently rigid so that the frame can reasonably be considered as shear-type and with additional eccentric mass for each floor. To the primary (linear) system, we connect two NESs, which are non-smooth and precisely the vibro-impact devices (VI-NESs), both placed on the top floor. In order to analyze the dynamics of the controlled model (structure with VI-NESs), we study the performance and the robustness of the augmented structure excited by a set of Eurocode8 (EC8) spectrum compliant earthquakes. Our purpose is to check the effectiveness of the VI-NESs to different earthquake excitations, that is, testing that an optimal VI-NES setting computed for a specific earthquake will still produce satisfactory results for the other earthquakes. We show that the nonlinear attachments are capable of engaging in transient resonance with linear modes at arbitrary frequencies by generating a one-way irreversible (on the average) transfer of the energy of vibration from the primary structure to local attachment. There the energy is confined and locally dissipated without “spreading” back to the main structure because of the instantaneous internal resonance. As energy decreases due to damping the conditions for Transient Resonance Capture (TRC) fail and escape from resonance capture takes place.

Efficient Targeted Energy Transfer With Parallel Nonlinear Energy Sinks: Theory and Experiments

2011 ◽  
Vol 6 (4) ◽  
Author(s):  
Bastien Vaurigaud ◽  
Alireza Ture Savadkoohi ◽  
Claude-Henri Lamarque
Keyword(s):  
Energy Transfer ◽  
Analytical Method ◽  
Nonlinear Energy Sink ◽  
Prototype System ◽  
Targeted Energy Transfer ◽  
Resonance Capture ◽  
Prototype Structure ◽  
Energy Sink ◽  
Nonlinear Energy ◽  
Theory And Experiments

In this paper the targeted energy transfer (TET) phenomenon between a linear multi-DOF master structure and several slave parallel nonlinear energy sink (NES) devices during a 1:1 resonance capture is investigated. An analytical method is proposed for tuning optimal NES parameters, which leads to efficient TETs. Then, the procedure is intentionally narrowed for a 4DOF master structure with two parallel NESs at the last DOF in order to grasp optimum NES parameters of a prototype structure that is built and tested at the Civil Engineering and Building Department Laboratory of the ENTPE. The aim is to control the first mode of the compound nonlinear prototype system by demonstrating the efficiency of designed parallel NESs by the suggested method.

Targeted Energy Transfer to a Rotary Nonlinear Energy Sink

2010 ◽  
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.

Targeted energy transfer in mechanical systems by means of non-smooth nonlinear energy sink

2011 ◽  
Vol 221 (1-2) ◽  
pp. 175-200 ◽  
Author(s):  
Claude-Henri Lamarque ◽  
Oleg V. Gendelman ◽  
Alireza Ture Savadkoohi ◽  
Emilie Etcheverria
Keyword(s):  
Energy Transfer ◽  
Mechanical Systems ◽  
Nonlinear Energy Sink ◽  
Targeted Energy Transfer ◽  
Energy Sink ◽  
Nonlinear Energy

Targeted energy transfer in stochastically excited system with nonlinear energy sink

2018 ◽  
Vol 30 (5) ◽  
pp. 869-886
Author(s):  
P. KUMAR ◽  
S. NARAYANAN ◽  
S. GUPTA
Keyword(s):  
Energy Transfer ◽  
Equations Of Motion ◽  
Nonlinear Energy Sink ◽  
Flow Dynamics ◽  
Slow Flow ◽  
Targeted Energy Transfer ◽  
Optimal Regime ◽  
Excited System ◽  
Energy Sink ◽  
Nonlinear Energy

This study investigates the phenomenon of targeted energy transfer (TET) from a linear oscillator to a nonlinear attachment behaving as a nonlinear energy sink for both transient and stochastic excitations. First, the dynamics of the underlying Hamiltonian system under deterministic transient loading is studied. Assuming that the transient dynamics can be partitioned into slow and fast components, the governing equations of motion corresponding to the slow flow dynamics are derived and the behaviour of the system is analysed. Subsequently, the effect of noise on the slow flow dynamics of the system is investigated. The Itô stochastic differential equations for the noisy system are derived and the corresponding Fokker–Planck equations are numerically solved to gain insights into the behaviour of the system on TET. The effects of the system parameters as well as noise intensity on the optimal regime of TET are studied. The analysis reveals that the interaction of nonlinearities and noise enhances the optimal TET regime as predicted in deterministic analysis.

Study of Targeted Energy Transfer Inside Three-Dimensional Acoustic Cavity by Two Nonlinear Membrane Absorbers and an Acoustic Mode

2016 ◽  
Vol 138 (3) ◽  
Author(s):  
Xian Wu ◽  
Jianwang Shao ◽  
Bruno Cochelin
Keyword(s):  
Energy Transfer ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Low Frequency ◽  
Nonlinear Energy Sink ◽  
Acoustic Mode ◽  
Targeted Energy Transfer ◽  
Working Zone ◽  
Acoustic Cavity ◽  
Acoustic Cavities

As a new approach to passive sound control in low-frequency domain, the targeted energy transfer (TET) phenomenon has been investigated inside a three-dimensional (3D) acoustic cavity by considering a two degrees-of-freedom (DOF) system with an acoustic mode and a membrane nonlinear energy sink (NES). The beginning of TET phenomenon of the 2DOF system and the desired working zone for the membrane NES have been defined. In order to enhance the robustness and the effective TET range in acoustic cavities, a 3DOF system with two membranes and one acoustic mode is studied in this paper. We consider two different membranes and two almost identical membranes to analyze the TET phenomenon, respectively. The desired working zone which was obtained by the 2DOF system is applied to analyze the 3DOF system. We observe that two membranes can enlarge the desired working zone.

Dynamics of an Eccentric Rotational Nonlinear Energy Sink

2011 ◽  
Vol 79 (1) ◽  
Author(s):  
O. V. Gendelman ◽  
G. Sigalov ◽  
L. I. Manevitch ◽  
M. Mane ◽  
A. F. Vakakis ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Nonlinear Energy Sink ◽  
Experimental Investigations ◽  
Primary System ◽  
Targeted Energy Transfer ◽  
Energy Sink ◽  
Nonlinear Energy

The paper introduces a novel type of nonlinear energy sink, designed as a simple rotating eccentric mass, which can rotate with any frequency and; therefore, inertially couple and resonate with any mode of the primary system. We report on theoretical and experimental investigations of targeted energy transfer in this system.

Mechanism of Optimal Targeted Energy Transfer

2016 ◽  
Vol 84 (1) ◽  
Author(s):  
Y. M. Wei ◽  
Z. K. Peng ◽  
X. J. Dong ◽  
W. M. Zhang ◽  
G. Meng
Keyword(s):  
Energy Transfer ◽  
Passive Control ◽  
Initial Conditions ◽  
Physical Phenomenon ◽  
Active Vibration Control ◽  
Design Procedure ◽  
Nonlinear Energy Sink ◽  
Targeted Energy Transfer ◽  
Active Vibration ◽  
Energy Sink

A novel nonlinear vibration reduction mechanism based on targeted energy transfer (TET) is proposed. Targeted energy transfer is a physical phenomenon that describes a one-way irreversible energy flow from a linear oscillator (LO) to a nonlinearizable (essentially) nonlinear auxiliary substructure, noted as nonlinear energy sink (NES). The optimal targeted energy transfer where NES is set on the optimal state is investigated in this study. Complexification-averaging methodology is used to derive the optimal TET of the undamped system for different initial conditions. It is revealed that the optimal TET is dependent on the energy, indicating that passive control of NES cannot be optimally set for arbitrary initial conditions. In addition, it is found that for the undamped system, the optimal phrase difference between the linear primary oscillator and the nonlinear attachment is π/2. From the perspective of active control, the NES can be taken as an actuator to keep the system vibrating on the optimal TET. An available modification form of the optimal equations is proposed for the impulse excitation with relatively small damping. The comparisons of the effectiveness of the optimal TET is validated by using numerical simulations with the excitations including impulse, harmonic, to input with sufficient bandwidth, and random signal. The design procedure would pave the way for practical implications of TET in active vibration control.

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