High‐frequency broadband radiation from panels and periodic structures including the effect of structural power flow on directivity

2006 ◽  
Vol 119 (5) ◽  
pp. 3419-3419
Author(s):  
Donald Bliss ◽  
Linda Franzoni ◽  
Pavel Danilov
Keyword(s):  
High Frequency ◽  
Power Flow ◽  
Periodic Structures ◽  
Structural Power ◽  
Broadband Radiation

Characterization of High Frequency Radiation From Panels Subject to Broadband Excitation

2008 ◽  
Author(s):  
Donald Bliss ◽  
Linda Franzoni ◽  
Krista Michalis
Keyword(s):  
High Frequency ◽  
Power Flow ◽  
Damping Ratio ◽  
Directivity Pattern ◽  
Point Of View ◽  
Flexural Wave ◽  
Dimensionless Frequency ◽  
Vehicle Interior ◽  
Broadband Radiation ◽  
Edge Radiation

In the high frequency limit, a vibrating panel subject to spatially-random temporally-broadband forcing is shown to have broadband power and directivity properties that can be expressed in simple analytical terms by a limited set of parameters. A lightly-loaded fixed-fixed membrane with a distribution of broadband uncorrelated drive points is analyzed. The theory is developed using classical modal methods and asymptotic modal analysis, assuming small damping. The power and directivity of the radiated pressure field are characterized in terms of structural wave Mach number, damping ratio, and dimensionless frequency. The relatively simple directivity pattern that emerges can be shown to arise from edge radiation. From the point of view of edge radiation, assuming a lightly damped reverberant structure, the same radiation formula and directivity pattern can be derived in a much simpler manner. Broadband radiation from structures with subsonic and supersonic flexural wave speeds is discussed and characterized in terms of a simple interpretation of the surface wavenumber spatial transform. The results show that the physical idea of interpreting edge radiation in terms of uncancelled volumetric sources is not correct, and the effect of higher order edge singularities is in fact very significant. The approach implies a relationship between radiation and structural power flow that is potentially useful in energy-intensity based prediction methods, and can be generalized to more complex structures with application to vehicle interior noise prediction.

Modeling of a high frequency ultrasonic transducer using periodic structures

2007 ◽  
Author(s):  
P. Maréchal ◽  
L. Haumesser ◽  
G. Feuillard ◽  
L.P. Tran-Huu-Hue ◽  
J. Holc ◽  
...  
Keyword(s):  
High Frequency ◽  
Periodic Structures ◽  
Ultrasonic Transducer

Power Flow and Energy Sharing between an Oscillator and a Continuous Receiver Structure

2011 ◽  
Vol 189-193 ◽  
pp. 1914-1917
Author(s):  
Lin Ji
Keyword(s):  
High Frequency ◽  
Power Flow ◽  
Energy Analysis ◽  
Statistical Energy Analysis ◽  
Coupled Subsystems ◽  
Modal Density ◽  
Vibration Problems ◽  
Energy Sharing ◽  
High Modal Density ◽  
Vibration Modeling

A key assumption of conventional Statistical Energy Analysis (SEA) theory is that, for two coupled subsystems, the transmitted power from one to another is proportional to the energy differences between the mode pairs of the two subsystems. Previous research has shown that such an assumption remains valid if each individual subsystem is of high modal density. This thus limits the successful applications of SEA theory mostly to the regime of high frequency vibration modeling. This paper argues that, under certain coupling conditions, conventional SEA can be extended to solve the mid-frequency vibration problems where systems may consist of both mode-dense and mode-spare subsystems, e.g. ribbed-plates.

scholarly journals Design and Implementation of 2.5kW IBFB-LLC DC/ DC Converter Using SiC Mosfet

2021 ◽  
Vol 31.2 (149) ◽  
pp. 7-14
Keyword(s):  
High Frequency ◽  
Power Flow ◽  
Input Voltage ◽  
Voltage Range ◽  
Zero Voltage Switching ◽  
Design And Implementation ◽  
Switching Losses ◽  
Power Switches ◽  
Isolation Transformer ◽  
Zero Voltage

Interleaved Boost Full Bridge integrated LLC resonant (IBFB- LLC) is an isolated DC/DC converter with directional power flow, which can cope with a wide input voltage range of PV applications. The main losses of the converter are switching losses of the power switches and transformers losses. This paper proposes a method to improve the efficiency of the IBFB converter due to zero voltage switching technique, in combination with employing new SiC MOSFET technology instead of the conventional Si MOSFET. In addition, Litz wire is also adopted to reduce the losses on the high frequency isolation transformer. Both numerical simulations and experiments with a prototype 2.5kW converter are implemented to verify the feasibility and effectiveness of the proposed solution.

Study and Implementation of Partial Resonant High-Frequency AC-Link Inverter Operating in Soft-Switching Condition

2021 ◽  
pp. 2150238
Author(s):  
Abdelkarim Aouiti ◽  
Hajer Marzougui ◽  
Faouzi Bacha
Keyword(s):  
High Frequency ◽  
Power Flow ◽  
Power Converter ◽  
Soft Switching ◽  
Correct Operation ◽  
Fundamental Properties ◽  
Dc Power ◽  
Dspace 1104 ◽  
Converter Topology ◽  
High Frequency Ac

In this paper, a high-frequency AC-link DC–AC converter is presented with detailed analysis. This converter is used as an interface between a dc power source and a grid. The studied converter is a universal power converter which consists of two bridges separated by an AC-link; each bridge is connected to a source or it feeds a load. The link of this converter contains a parallel pair inductance-capacitor. The inductance is used to stock/supply energy and for the link capacitor, it allows to perform soft switching during turning on/turning off of the switches. The studied converter has considerable advantages compared to the other topologies. Its fundamental properties are, especially, the compactness, reliability and efficiency which it ensures. Also, it guarantees longer lifetime and the possibility to transfer power in the two power flow directions. In this talk, the principles of the ac-link inverter operation are clearly explained in this paper. Simulation results, under MATLAB/SIMULINK, are shown to validate the correct operation and the efficiency of the proposed converter topology. The control algorithm is, also, experimentally implemented using a dSPACE 1104 control board.

scholarly journals Localizing Energy Sources and Sinks in Plates Using Power Flow Maps Computed From Laser Vibrometer Measurements

1998 ◽  
Vol 5 (4) ◽  
pp. 235-253 ◽  
Author(s):  
J.R.F. Arruda ◽  
P. Mas
Keyword(s):  
Power Flow ◽  
Finite Difference Methods ◽  
Laser Vibrometer ◽  
Structural Power ◽  
Sources And Sinks ◽  
Vibration Data ◽  
Flow Maps ◽  
Fourier Series Approximation ◽  
Spatial Derivatives ◽  
Difference Methods

This paper presents an experimental method especially adapted for the computation of structural power flow using spatially dense vibration data measured with scanning laser Doppler vibrometers. In the proposed method, the operational deflection shapes measured over the surface of the structure are curve-fitted using a two-dimensional discrete Fourier series approximation that minimizes the effects of spatial leakage. From the wavenumber-frequency domain data thus obtained, the spatial derivatives that are necessary to determine the structural power flow are easily computed. Divergence plots are then obtained from the computed intensity fields. An example consisting of a rectangular aluminum plate supported by rubber mounts and excited by a point force is used to appraise the proposed method. The proposed method is compared with more traditional finite difference methods. The proposed method was the only to allow the localization of the energy source and sinks from the experimental divergence plots.

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