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Numerical and experimental studies of a flat acoustic source that is actuated by an integrated flexure-based piezoelectric mechanism

Tajdari, F. (author), Berkhoff, A.P. (author), de Boer, A. (author)

This paper focuses on extensive numerical and experimental investigations of a thin sandwich acoustic source. Due to an energy inefficient actuation design, a thin sandwich acoustic source that was proposed in an early study is redesigned and reconstructed in the current research. The thin acoustic source in the present paper is actuated by long...

article 2020

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The influence of energy recovery on the overall efficiency of acoustic sources at low frequencies

Tajdari, F. (author), Berkhoff, A.P. (author), van der Zee, R.A.R. (author), de Boer, A. (author)

article 2020

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Numerical modeling of a flexural displacement-converter mechanism to excite a flat acoustic source driven by piezoelectric stack actuators

Tajdari, F. (author), Berkhoff, A.P. (author), de Boer, A. (author)

This paper studies an acoustic source with a relatively small thickness and a high bending stiffness. The acoustic source operates in the low frequency, quasi-static regime. The focus of the current study is on the actuation part in order to design an appropriate excitation mechanism. A flexural mechanism is modeled in combination with a...

article 2020

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Numerical modeling of alumpedacoustic source actuated by a piezoelectric stack device that is driven by a switching amplifier

Tajdari, F. (author), Berkhoff, A.P. (author), de Boer, A. (author)

This paper studies an acoustic source with a relatively small thickness and high bending stiffness. Piezoelectric actuators are used to drive the moving component of the acoustic source. In the current study, a lumped model is used to represent the acoustic source that is excited by a piezoelectric stacked actuator. The equivalent electrical...

conference paper 2018

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The effect of floating deck structures on underwater radiated noise

Bosschaart, C. (author), Jansen, H.W. (author), de Jong, C.A.F. (author), Basten, T. (author)

A concept for underwater machinery noise mitigation of future civil and military ships is the application of a common deck structure, supporting multiple machines, which is installed on resilient mounts on the ship's foundation structure. TNO is addressing the availability and testing of tools to be able to set realistic targets for the radiated...

conference paper 2017

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Active control of a lumped acoustic source driven by various actuators

Tajdari, F. (author), Berkhoff, A.P. (author), de Boer, A. (author)

This paper studies a lumped model of an acoustic source with a relatively small thickness and high bending stiffness. Voice coil and piezoelectric actuators are used to drive moving components of the acoustic source. Feedback and feedforward damping control techniques are used to actively obtain a smooth frequency response, especially at low...

conference paper 2017

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Numerical modeling of electrical-mechanical-acoustical behavior of a lumped acoustic source driven by a piezoelectric stack actuator

Tajdari, F. (author), Berkhoff, A.P. (author), de Boer, A. (author)

The present work describes the electrical, mechanical and acoustical behavior of a thin honey-comb structure as an acoustic source. The acoustic source has to operate in the low frequency, quasi-static regime and is driven by a piezoelectric stack actuator. In addition, a two-way energy flow between the actuator and a connected amplifier is...

conference paper 2016

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Flat acoustic sources with frequency response correction based on feedback and feed-forward distributed control

Ho, J.H. (author), Berkhoff, A.P. (author)

This paper presents an acoustic source with a small thickness and high bending stiffness. The high bending stiffness is obtained with a sandwich structure in which the face of the sandwich structure internal to the source is perforated to increase the acoustic compliance, thereby leading to increased electroacoustic conversion efficiency....

article 2015

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Uncertainty quantification of aeroacoustic power sources in corrugated pipes

Swamy, M. (author), Shoeibi Omrani, P. (author), González Díez, N. (author)

Gas transport in corrugated pipes often exhibit whistling behavior, due to periodic flow-induced pulsations generated in the pipe cavities. These aero-acoustic sources are strongly dependent on the geometrical dimensions and features of the cavities. As a result, uncertainties in the exact shape and geometry play a significant role in...

conference paper 2015

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Acoustic measurements of models of military style supersonic nozzle jets

Kuo, C.W. (author), Veltin, J. (author), McLaughlin, D.K. (author)

Modern military aircraft jet engines are designed with variable-geometry nozzles to provide optimal thrust in different operating conditions, depending on the flight envelope. However, acoustic measurements for such nozzles are scarce, due to the cost involved in making full-scale measurements and the lack of details about the exact geometries...

article 2014

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Local impact assessment of urban traffic noise

Salomons, E.M. (author), Janssen, S.A. (author), Verhagen, H.L.M. (author)

article 2014

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Assessment of reflectivity of noise barriers in the far field – QUIESST method compared to traditional approach

de Roo, F. (author)

The sound reflectivity of noise barriers elements is one of the major acoustic product characteristics. Traditionally this property was tested in reverberation rooms according to EN 1793-1 and the results were used to predict the effect of sound reflections in the far field. As in many cases these results cannot be used directly to assess the...

conference paper 2013

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QUIESST, toward a better knowledge and understanding of how efficient noise barriers could actually be: Noise in the built environment

Clairbois, J.-P. (author), de Roo, F. (author), Garai, M. (author), Conter, M. (author), Defrance, J. (author), Oltean-Dumbrava, C. (author), Fusco, I. (author)

Since the early 80's, one models noise propagation, in the early 90's one started to standardize how to measure the intrinsic characteristics of manufactured noise barriers: in 1997, the EU funded ADRIENNE research ([1] and [2]) was a first step, but many problems still remained. Since years, all the noise propagation software are still modeling...

conference paper 2010

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The acoustic source strength of high-energy blast waves: combining measurements and a non-linear model

van der Eerden, F.J.M. (author), van der Berg, F. (author)

In the densely populated area of the Netherlands, the objective of the Netherlands Ministry of Defence is to find an optimal balance between military training and the impact on the surrounding civilian community. A special case concerns large weapons, such as artillery or demolitions, which create high-energy blast waves. These waves have a low...

conference paper 2010

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Noise barriers and the harmonoise sound propagation model

Salomons, E.M. (author), van Maercke, D. (author), Randrianoelina, A. (author), TNO Bouw en Ondergrond (author)

The Harmonoise sound propagation model ('the Harmonoise engineering model') was developed in the European project Harmonoise (2001-2004) for road and rail traffic noise. In 2008, CSTB Grenoble and TNO Delft have prepared a detailed description of the various steps involved in a calculation with the Harmonoise model. In the course of this joint...

conference paper 2009

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Quantifying the intelligibility of speech in noise for non-native listeners

van Wijngaarden, S.J. (author), Steeneken, H.J.M. (author), Houtgast, T. (author), TNO Technische Menskunde (author)

article 2002

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A-weighted equivalent sound level as a predictor of the annoyance caused by road traffic consisting of various proportions of light and heavy vehicles

TNO Human Factors (author), Versfeld, N.J. (author), Vos, J. (author)

A laboratory study was conducted to examine the relationship between noise annoyance and the proportion of heavy vehicles in a mixture of trucks and passenger cars. Twenty normal-hearing subjects were asked to judge the annoyance caused by the sounds from a continuous stream of vehicles, assuming they were exposed to it at home on a regular...

article 2002

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Model-based acoustic substitution source methods for assessing shielding measures applied to trains

Geerlings, A.C. (author), Thompson, D.J. (author), Verheij, J.W. (author), Technisch Physische Dienst TNO - TH (author)

A promising means of reducing the rolling noise from trains is local shielding in the form of vehicle-mounted shrouds combined with low trackside barriers. This is much less visually intrusive than classic lineside noise barriers. Various experimental methods have been proposed that allow the performance to be assessed under static conditions,...

article 2001

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Improved measurement methods for railway rolling noise

Dittrich, M.G. (author), Janssens, M.H.A. (author), Technisch Physische Dienst TNO - TH (author)

Some of the issues related to railway noise type testing are discussed and potential improvements to existing procedures are put forward. New and improved methods that also go beyond the scope of type testing are presented that help to characterize and analyze rolling noise more accurately. These methods are indirect measurement of total wheel...

article 2000

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Measuring TGV source strength with Syntacan

van der Toorn, J.D. (author), Hendriks, H. (author), van den Dool, T.C. (author)

A 10 m high, vertical, synthetic acoustic antenna (Syntacan) has been used to measure the acoustic source strength and the vertical source distribution of a French TGV, as a function of the speed of the train, the frequency of the sound and the coach type (passenger coach, power car). The results are intended as input for calculation schemes and...

article 1996