Nonlinear Energy Sink for Whole-Spacecraft Vibration Reduction

2017 ◽  
Vol 139 (2) ◽  
Author(s):  
Kai Yang ◽  
Ye-Wei Zhang ◽  
Hu Ding ◽  
Tian-Zhi Yang ◽  
Yang Li ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Natural Frequencies ◽  
Vibration Reduction ◽  
Nonlinear Energy Sink ◽  
Element Model ◽  
Equivalent Model ◽  
Energy Sink ◽  
The Finite Element Model ◽  
Nonlinear Energy

A nonlinear energy sink (NES) approach is proposed for whole-spacecraft vibration reduction. Frequency sweeping tests are conducted on a scaled whole-spacecraft structure without or with a NES attached. The experimental transmissibility results demonstrate the significant reduction of the whole-spacecraft structure vibration over a broad spectrum of excitation frequency. The NES attachment hardly changes the natural frequencies of the structure. A finite element model is developed, and the model is verified by the experimental results. A two degrees-of-freedom (DOF) equivalent model of the scaled whole-spacecraft is proposed with the two same natural frequencies as those obtained via the finite element model. The experiment, the finite element model, and the equivalent model predict the same trends that the NES vibration reduction performance becomes better for the increasing NES mass, the increasing NES viscous damping, and the decreasing nonlinear stiffness. The energy absorption measure and the energy transition measure calculated based on the equivalent model reveals that an appropriately designed NES can efficiently absorb and dissipate broadband-frequency energy via nonlinear beats, irreversible targeted energy transfer (TET), or both for different parameters.

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.

Hydroelastic Modal Analysis of the Perforated Cylindrical Shell in SMART

2011 ◽  
Author(s):  
Youngin Choi ◽  
Seungho Lim ◽  
Kyoung-Su Park ◽  
No-Cheol Park ◽  
Young-Pil Park ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Dynamic Characteristics ◽  
Natural Frequencies ◽  
Element Model ◽  
Mode Shapes ◽  
Steam Generators ◽  
Structure Interaction ◽  
The Finite Element Model ◽  
Reactor Internals

The System-integrated Modular Advanced ReacTor (SMART) developed by KAERI includes components like a core, steam generators, coolant pumps, and a pressurizer inside the reactor vessel. Though the integrated structure improves the safety of the reactor, it can be excited by an earthquake and pump pulsations. It is important to identify dynamic characteristics of the reactor internals considering fluid-structure interaction caused by inner coolant for preventing damage from the excitations. Thus, the finite element model is constructed to identify dynamic characteristics and natural frequencies and mode shapes are extracted from this finite element model.

scholarly journals Applied theory of bending vibration of the piezoelectric and piezomagnetic bimorph

2020 ◽  
Vol 10 (03) ◽  
pp. 2050007
Author(s):  
Do Thanh Binh ◽  
V. A. Chebanenko ◽  
Le Van Duong ◽  
E. Kirillova ◽  
Pham Manh Thang ◽  
...  
Keyword(s):  
Finite Element ◽  
Variational Principle ◽  
Boundary Conditions ◽  
Finite Element Model ◽  
Natural Frequencies ◽  
Element Model ◽  
Applied Theory ◽  
Bending Vibration ◽  
Steady Vibrations ◽  
The Finite Element Model

Based on the variational principle, equations and boundary conditions for transverse steady vibrations of a bimorph consisting of a piezoelectric and piezomagnetic layers are obtained. The results of calculations of natural frequencies are compared with the finite element model of the device in ACELAN.

scholarly journals DEVELOPMENT OF A DESIGN METHOD FOR DETERMINING THE ATTACHMENT OF THE EXHAUST MOUNTING MOUNTS

Akustika ◽  
2019 ◽  
Vol 34 ◽  
pp. 141-147
Author(s):  
Rakhmatjon Rakhmatov ◽  
Vitaliy Krutolapov ◽  
Valeriy Zuzov
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Strain Energy ◽  
Natural Frequencies ◽  
Design Method ◽  
Exhaust System ◽  
Element Model ◽  
Vehicle Body ◽  
Vibration Modes ◽  
The Finite Element Model

The article presents the developed method of determining the attachment points of the mounts of the exhaust system to the vehicle body. The requirements for the construction of a finite element model of the exhaust system are presented, the finite element model of the exhaust system is created, the results of natural frequencies and vibration modes and the strain energy of the structure are shown.

scholarly journals Vibration Suppression for Beam-Like Repeating Lattice Structure Based on Equivalent Model by a Nonlinear Energy Sink

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Gen Liu ◽  
Gongfa Chen ◽  
Fangsen Cui
Keyword(s):  
Vibration Suppression ◽  
Lattice Structure ◽  
Vibration Reduction ◽  
Coupled System ◽  
Nonlinear Energy Sink ◽  
Equivalent Model ◽  
External Excitation ◽  
Suppression Effect ◽  
Energy Sink ◽  
Nonlinear Energy

Based on the fully deployed space beam-like truss, the vibration reduction of the lattice structure is studied by using the local NES (nonlinear energy sink) attachment in this paper. The beam-like lattice structure is modeled as an equivalent linear continuous system (a finite length beam) by the equivalent method and validated with the finite element results. The dynamic vibration equations for the equivalent cantilever beam are established and the governing equations for the equivalent beam with NES are approximated by the Galerkin method. The displacement responses of the beam with and without NES attached under shock excitation are obtained. With NES at different positions, the amplitude responses of the coupled system under the external excitation at different positions are calculated to evaluate the suppression effect of the NES attachment to the structure. And with different masses of the NES, the amplitude responses of the coupled structure subject to the external excitation at different positions are also investigated to get the influence of the mass of the NES attachment to the vibration reduction. It can be seen from the results that the NES attachment can attenuate the response of the beam-like truss under transient excitation efficiently. And with the mass of NES attachment increasing, the vibration amplitude of the coupled system declines more rapidly, and the energy consumption efficiency of the NES attachment is higher. Moreover, the attenuation effect of the NES with different masses is experimentally analyzed. The experimental results are in good accord with the theoretical calculation.

Factors Influencing Natural Frequencies in a Prestressed Concrete Panel for Damage Detection

2014 ◽  
Vol 69 (3) ◽  
Author(s):  
L. D. Goh ◽  
A. A. Rahman ◽  
N. Bakhary ◽  
B. H. Ahmad
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Damage Detection ◽  
Prestressed Concrete ◽  
Natural Frequencies ◽  
Element Model ◽  
Modal Parameters ◽  
Actual Structure ◽  
Modal Test ◽  
The Finite Element Model

Modal parameters such as natural frequencies, mode shapes, and damping ratios are widely used as damage indicators in the field of vibration-based damage detection. These modal parameters can be easily obtained by conducting the modal test on the actual structure or from the finite element model. However, many publications are focusing only on the relationship between the modal parameters and the changes in structural properties for damage detection. There are a limited number of publications discussing on the factors that may affect the modal parameters for damage detection. Hence, this paper provides a study on the level of influence of several factors on the natural frequencies of a prestressed concrete panel. The factors that are considered in this study are the size of element used in the numerical model, the dimension of the structural element, and the prestressing force applied in the prestressed concrete panel. The natural frequencies computed from the finite element model are also verified with the actual measured natural frequencies that are determined through the modal test conducted in the laboratory. 

scholarly journals Experimental Studies on Finite Element Model Updating for a Heated Beam-Like Structure

2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
Kaipeng Sun ◽  
Yonghui Zhao ◽  
Haiyan Hu
Keyword(s):  
Finite Element ◽  
High Temperature ◽  
Finite Element Model ◽  
Natural Frequencies ◽  
Model Updating ◽  
Element Model ◽  
Modal Parameters ◽  
Finite Element Model Updating ◽  
Time Varying ◽  
The Finite Element Model

An experimental study was made for the identification procedure of time-varying modal parameters and the finite element model updating technique of a beam-like thermal structure in both steady and unsteady high temperature environments. An improved time-varying autoregressive method was proposed first to extract the instantaneous natural frequencies of the structure in the unsteady high temperature environment. Based on the identified modal parameters, then, a finite element model for the structure was updated by using Kriging meta-model and optimization-based finite-element model updating method. The temperature-dependent parameters to be updated were expressed as low-order polynomials of temperature increase, and the finite element model updating problem was solved by updating several coefficients of the polynomials. The experimental results demonstrated the effectiveness of the time-varying modal parameter identification method and showed that the instantaneous natural frequencies of the updated model well tracked the trends of the measured values with high accuracy.

scholarly journals Experimental Study on Vibration of a Rotating Blade

1993 ◽  
Author(s):  
Y. C. Fan ◽  
M. S. Ju ◽  
Y. G. Tsuei
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Natural Frequencies ◽  
Beam Theory ◽  
Element Model ◽  
Element Analysis ◽  
Rotating Speed ◽  
Rotating Blade ◽  
Experimental Values ◽  
The Finite Element Model

The vibration of a rotating blade is investigated in this work. A rotor system is built and natural frequencies of the rotating blade are measured and compared with the numerical results from a finite element analysis. The experimental setup has a strain gage-based telemetry system and a piezoelectric shaker that rotates with the rotor. The finite element model of the beam is derived based on the Timoshenko beam theory. The effects of varying rotating speeds and stagger angles on the blade natural frequencies are studied. The results indicate that the natural frequencies calculated from the finite element model and the experimental values are in good agreement. It is found that the blade natural frequencies increase with the rotating speed in a nonlinear linear way. The effects of the stagger angle on the measured natural frequencies are not clear.

Experimental Study on Vibration of a Rotating Blade

1994 ◽  
Vol 116 (3) ◽  
pp. 672-677 ◽  
Author(s):  
Y. C. Fan ◽  
M. S. Ju ◽  
Y. G. Tsuei
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Natural Frequencies ◽  
Beam Theory ◽  
Element Model ◽  
Element Analysis ◽  
Rotating Speed ◽  
Rotating Blade ◽  
Experimental Values ◽  
The Finite Element Model

The vibration of a rotating blade is investigated in this work. A rotor system is built and natural frequencies of the rotating blade are measured and compared with the numerical results from a finite element analysis. The experimental setup has a strain-gage-based telemetry system and a piezoelectric shaker that rotates with the rotor. The finite element model of the beam is derived based on the Timoshenko beam theory. The effects of varying rotating speeds and stagger angles on the blade natural frequencies are studied. The results indicate that the natural frequencies calculated from the finite element model and the experimental values are in good agreement. It is found that the blade natural frequencies increase with the rotating speed in a nonlinear way. The effects of the stagger angle on the measured natural frequencies are not clear.

scholarly journals Updating the finite element model of a Colombian Bridge with Ansys

DYNA ◽  
2020 ◽  
Vol 87 (212) ◽  
pp. 209-218
Author(s):  
Diego Sequera Gutierrez ◽  
Luis Felipe Solano Rodríguez ◽  
Edgar Eduardo Muñoz Díaz ◽  
Yezid Alexander Alvarado Vargas ◽  
Jesús Daniel Villalba Morales ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Structural Model ◽  
Natural Frequencies ◽  
Element Model ◽  
Ambient Vibration ◽  
Normal Operation ◽  
Design Variables ◽  
Ambient Vibration Measurements ◽  
The Finite Element Model

Updating structural model is a knowledge field that have been studied in the last decades to guarantee the reliability on the model defined to represent the behavior of a structure, but generally implies the use of different software to carry out the different parts of the process. This paper presents the updating of the finite element model of a curve-alignment reinforced concrete bridge located near to the city of Ubaté in Colombia by using the optimization tool available in software Ansys and ambient vibration measurements. The use of such type of information avoids to carry out forced-vibration test, which affect the normal operation of the bridge. The objective function corresponds to the minimization of the error between analytical and experimental natural frequencies of the bridge. The design variables correspond to the material properties of the concrete and the elastomeric bearings. Results show that the error was decreased to less than 2%. The sensibility analysis allowed to determine which variables are more sensible to affect the natural frequencies in the structure.

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