Spectral Element Approach for Flexural Waves Control in Smart Material Beam With Single and Multiple Resonant Impedance Shunt Circuit

2020 ◽  
Vol 15 (12) ◽  
Author(s):  
Marcela R. Machado ◽  
Adriano T. Fabro ◽  
Braion B. de Moura
Keyword(s):  
Control Strategies ◽  
Spectral Element ◽  
Smart Material ◽  
Smart Structure ◽  
Flexural Waves ◽  
Structural Dynamic ◽  
Vibration Attenuation ◽  
Resonant Behavior ◽  
Element Approach ◽  
Shunt Circuit

Abstract The accurate prediction of the dynamic characteristics of a structure is key to successful vibration control strategies. A typical vibration and wave propagation control is performed through periodic and shunted piezoelectric patches, also known as a smart material. Therefore, the smart metamaterial considers periodic arrangement of shunted piezoelectric patches providing a beam with attenuation properties which depend on the resonant behavior of the shunts. The vibration attenuation occurs due to an elastic-electrical system characterized by an internal resonance of the shunt circuit. The spectral element approach provides very accurate solutions for the structural dynamic response. In this paper, a beam-piezoelectric structure is introduced to focus on the control of flexural waves in beams with piezolayers connected to single and multiresonant shunt approaches. The smart structure is modeled using the spectral element method. It is shown that the effective wavenumber presents the locally resonant behavior at the same frequencies of the vibration attenuation for both single and multishunt approached, indicating that each shunt circuit is independently associated with a attenuation frequency. The spectral element approach presented in this paper shows to be an accurate and simple approach for the design smart metamaterial beams.

scholarly journals Review of Experimental-Numerical Methodologies and Challenges for Floating Offshore Wind Turbines

2020 ◽  
Vol 19 (3) ◽  
pp. 339-361
Author(s):  
Peng Chen ◽  
Jiahao Chen ◽  
Zhiqiang Hu
Keyword(s):  
Control Strategies ◽  
Full Scale ◽  
Dynamic Responses ◽  
Offshore Wind ◽  
Structural Dynamic ◽  
Hybrid Approaches ◽  
Global Dynamic ◽  
Floating Offshore Wind Turbines ◽  
Calibration Methods ◽  
Industrial Projects

Abstract Due to the dissimilar scaling issues, the conventional experimental method of FOWTs can hardly be used directly to validate the full-scale global dynamic responses accurately. Therefore, it is of absolute necessity to find a more accurate, economic and efficient approach, which can be utilized to predict the full-scale global dynamic responses of FOWTs. In this paper, a literature review of experimental-numerical methodologies and challenges for FOWTs is made. Several key challenges in the conventional basin experiment issues are discussed, including scaling issues; coupling effects between aero-hydro and structural dynamic responses; blade pitch control strategies; experimental facilities and calibration methods. Several basin experiments, industrial projects and numerical codes are summarized to demonstrate the progress of hybrid experimental methods. Besides, time delay in hardware-in-the-loop challenges is concluded to emphasize their significant role in real-time hybrid approaches. It is of great use to comprehend these methodologies and challenges, which can help some future researchers to make a footstone for proposing a more efficient and functional hybrid basin experimental and numerical method.

scholarly journals Research of Jiles-Atherton Dynamic Model in Giant Magnetostrictive Actuator

2016 ◽  
Vol 2016 ◽  
pp. 1-8
Author(s):  
Yongguang Liu ◽  
Xiaohui Gao ◽  
Chunxu Chen
Keyword(s):  
Mathematical Model ◽  
Dynamic Model ◽  
Control Strategies ◽  
Structural Parameters ◽  
Hysteresis Loops ◽  
Structural Dynamic ◽  
Magnetostrictive Actuator ◽  
Output Characteristics ◽  
And Control ◽  
Minor Hysteresis Loops

Due to the existence of multicoupled nonlinear factors in the giant magnetostrictive actuator (GMA), building precise mathematical model is highly important to study GMA’s characteristics and control strategies. Minor hysteresis loops near the bias magnetic field would be often applied because of its relatively good linearity. Load, friction, and disc spring stiffness seriously affect the output characteristics of the GMA in high frequency. Therefore, the current-displacement dynamic minor loops mathematical model coupling of electric-magnetic-machine is established according to Jiles-Atherton (J-A) dynamic model of hysteresis material, GMA structural dynamic equation, Ampere loop circuit law, and nonlinear piezomagnetic equation and demonstrates its correctness and effectiveness in the experiments. Finally, some laws are achieved between key structural parameters and output characteristics of GMA, which provides important theoretical foundation for structural design.

Acoustic Radiation Models of Brake Systems From Stationary LDV Measurements

1999 ◽  
Author(s):  
J. Gregory McDaniel ◽  
James Moore ◽  
Shih-Emn Chen ◽  
Cory L. Clarke
Keyword(s):  
Natural Frequencies ◽  
Acoustic Radiation ◽  
Brake System ◽  
Normal Velocity ◽  
Flexural Waves ◽  
High Radiation ◽  
Radiation Mechanisms ◽  
Resonant Behavior ◽  
Insight Into ◽  
Approach Unity

Abstract This paper presents a study of the acoustic radiation from a stationary brake system that was conducted in order to better understand the acoustic radiation from squealing brake systems. A large class of squeal mechanisms are associated with the resonant behavior of an operating brake system. In this work, an analysis is presented that equates the natural frequencies and modes of a mechanically-excited stationary brake system to those of an operating brake system. The equivalence allows one to conduct experiments on stationary brake systems in order to gain insight into the acoustic radiation mechanisms of squealing systems, which is a substantial convenience given the difficulty of artificially inducing squeal. The methodology is applied to scanning LDV measurements of the normal velocity of a shaker-excited stationary brake system. Acoustic radiation efficiencies and intensities of the modes were computed by importing the experimentally measured velocities into a BEM software package. These efficiencies approach unity at a coincidence frequency defined by comparing acoustic wavelengths to the wavelengths of flexural waves that propagate circumferentially around the rotor. For the particular system tested, this remarkably high radiation efficiency occurred at frequencies above 2–3 kHz.

A spectral boundary element approach to three-dimensional Stokes flow

1995 ◽  
Vol 298 ◽  
pp. 167-192 ◽  
Author(s):  
G. P. Muldowney ◽  
J. J. L. Higdon
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Spectral Element ◽  
Companion Paper ◽  
Porous Membrane ◽  
Boundary Integral ◽  
Boundary Integral Method ◽  
Reynolds Number Flow ◽  
Periodic Models ◽  
Element Approach

A novel method is introduced for solving the three-dimensional Stokes equations via a spectral element approach to the boundary integral method. The accuracy and convergence of the method are illustrated through applications involving rigid particles, deformable droplets and interacting particles. New physical results are obtained for two applications in low Reynolds number flow: the permeability of periodic models of a porous membrane and the instability of a toroidal droplet subject to non-axisymmetric perturbations. Further applications are described in the companion paper (Higdon & Muldowney 1995).

Performance Analysis and Experimental Verification for FBG Sensors Applied for Smart Structure

2007 ◽  
Vol 336-338 ◽  
pp. 1357-1360 ◽  
Author(s):  
Xi Yuan Chen ◽  
Lin Fang
Keyword(s):  
Experimental Method ◽  
Temperature Sensor ◽  
Thermal Strain ◽  
Smart Material ◽  
Smart Structure ◽  
Experimental Result ◽  
Bragg Grating ◽  
Material Structure ◽  
Fiber Sensors ◽  
Fbg Sensors

Among a variety of fiber sensors, the fiber Bragg grating (FBG) sensor has numerous advantages over other optical fiber sensors. One of the major advantages of this type of sensors is attributed to wavelength-encoded information given by the Bragg grating. Since the wavelength is an absolute parameter, signal from FBG may be processed such that its information remains immune to power fluctuations along the optical path. This inherent characteristic makes the FBG sensors very attractive for application in smart material structure, health monitoring field et al. But FBG sensors are sensitive to temperature and strain simultaneously; it is necessary to analyze the characteristics of temperature and strain of FBG applied for smart structure. Short overview of the FBG sensing principle as well as theoretical analyses is presented at first; then the paper proposes a simple, convenient, and low cost experimental method to verify the performance of FBGs. The improved high-accuracy experimental instrument of thermal deformation, which consists of an accurate temperature controlling and measuring subsystem, supporting and adjusting subsystem, collimating and positioning subsystem and fine motion and measuring sub-system, is simply introduced. The proposed experimental method involves bonding one uniform FBG to the center of the pole, which is about 89.5mm long; another FBG temperature sensor is free in the temperature-control box. The temperature in the box is -20°C-+50°C is adjusted according to experimental schedule. The characteristics of the FBG are analyzed by actual datum, which are simultaneously collected by a PC through a FBG interrogator. Comparing the data of FBG bonded to the pole with another FBG temperature sensor in the free state, the characteristics of the temperature and the thermal strain of the FBG can be obtained. The experimental result shows the FBGs used to the smart material have good agreement characteristics with theoretical calculation of the FBGs.

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