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1
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Reduction of Vibration of Fluid Loaded Plate with Piezoelectric Elements - a Comparison of Analytical, FEM Harmonic Analysis, and Real Results

100%
Iwański D., Wiciak J.
Acta Physica Polonica A
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2013
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vol. 123
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issue 6
1040-1043
EN
In the present paper, a comparison of analytical calculations, FEM harmonic analysis, and real data from laboratory stand of fluid-loaded structure were taken under consideration. Resonant frequencies of the investigated structure were measured using swept sine technique on laboratory stand. Analytical calculations of the first twelve modes were made and the numerical model was build using the finite element method. Results from real data, analytical calculations, and numerical calculations are comparable.
2
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Comparison of Passive and Active Methods for Minimization of Sound Radiation by Vibrating Clamped Plate

100%
Kozupa M., Wiciak J.
Acta Physica Polonica A
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2011
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vol. 119
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issue 6A
1013-1017
EN
The paper is an analytical and experimental study of a smart structure consisting of steel plate with bonded piezoelectric transducers and porous elastomer layer. Active control of sound radiation from a plate clamped at the edge square is examined. Simulations and numerical computation of the experiment are performed in Ansys environment. Calculations of plate vibration and sound radiation under stepped harmonic force are performed. The experimental setup consists of two rooms with the test opening in between. A variety of test cases were studied for three different configurations: steel plate + piezoelectric transducer, steel plate + elastomer layer, steel plate + piezoelectric transducer + elastomer layer. The aim of the paper is to illustrate the possibilities of using piezoelectric materials as an active control with elastomer layers as passive methods in one structure to improve the transmission loss.
3
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The Influence of Alarm Siren Structure Parameters on Output Sound Pressure Level

100%
Wiciak J., Dąbrowski K.
Acta Physica Polonica A
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2012
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vol. 121
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issue 1A
A-136-A-141
EN
The paper is a discussion of the construction of an alarm siren based on the active piezoelectric element. The influence of various parameters on the loudness of the siren was investigated. Efforts to increase the efficiency of selected design were made. The simulations carried out based on an ANSYS. Individual dimensions of a piezoelectric transducer were selected as well as a collaborate diaphragm. The possibility of using different piezoelectric materials was also analyzed. All tasks and computer simulations were aimed at receiving a siren structure able to obtain the highest sound pressure level at selected frequency.
4
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Active Vibration Control of Rectangular Plate with Distributed Piezoelements Excited Acoustically and Mechanically

100%
Kozupa M., Wiciak J.
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issue 1
95-98
EN
The paper presents simulations and research results of testing of the aluminium plate with active vibration control. The aim of this paper is to analyze and compare two ways of excitation of the test plate, various influence on its vibrations and active damping control. Vibration control of the smart structure is realized through four piezoceramic PZT actuators and one PZT sensor bonded to the plate. Simulations and numerical computations of the structure are performed in ANSYS environment. Measurements are executed on specialized sound insulation suite for small elements in reverberation chamber. At the beginning white noise sound source is used in purpose to measure basic vibration modes. After numerical computations and measurements three particular frequencies has been chosen and for them active damping is applied. There are two ways of exciting the test plate; first method is sound wave, second is mechanical vibrations via one of piezoceramics. The test results indicate that PZTs can decrease vibrations by approximately 15 dB for a pure sound input with acoustic excitation method, for mechanical excitation method 18 dB for a sinus vibration signal is achieved.
5
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Sound Pressure Level Analysis of Commercials and Regular Programs

100%
Malecki P., Wiciak J.
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issue 1
118-122
EN
Popularity of television and multitude of commercials during the TV broadcast lead to the analysis of its sound levels. Costs of commercials' time cause producers to make commercials much louder than a regular TV program. The article shows results of commercials and regular program sound level (RMS and FFT) analysis and the difference in sound levels of commercials compared to a regular program. The analysis also shows the difference between public and private TV. The authors of the article suggest a solution to this problem and its effects.
6
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Structural Noise Reduction and Its Effects on Plate Vibrations

100%
Trojanowski R., Wiciak J.
Acta Physica Polonica A
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2012
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vol. 121
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issue 1A
A-148-A-151
EN
The aim of this work is reduction of structural noise generated by plate and its impact on plates vibrations. For this purpose a one-side clamped aluminum plate with 5 piezo elements attached is used. One of the elements is used for plate excitation, two as vibration sensors, and two as actuators. Structural noise is measured by a microphone connected with SVAN 912 E. Study was divided into three parts: measurements of vibrations and noise generated by excited plate, active vibration control, and structural noise reduction. A significant noise local noise reduction is obtained, although with increase in plate vibrations.
7
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Design of Band-Gap Structures from Sheet Metal

100%
Iwański D., Wiciak J.
Acta Physica Polonica A
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2011
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vol. 119
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issue 6A
972-976
EN
Two-dimensional, circular plate was taken under consideration to design a band-gap structure. The analytical model was built using the Bessel functions and at the end the numerical examples were presented using MatLab and Ansys software. Results show that it is possible to create a band-gap structure, however further verification analysis must be made to improve given solution.
8
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Comparison of Efficiency of Different Shapes of Homogeneous and Two-Part Piezo Elements on Vibration Reduction

100%
Trojanowski R., Wiciak J.
Acta Physica Polonica A
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2012
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vol. 122
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issue 5
905-907
EN
The subject of this work is a numerical analysis of efficiency of different piezo element shapes and types used for vibration (and later structural sound) reduction. The shapes of both types of piezo elements used are as follows: square, right-angled triangle, and parallelogram. There are 2 types of piezo elements used in this study: homogeneous elements and elements consisting of 2 parts (inner and outer) of different composition. These are attached to steel plate clamped on all sides. For every simulation 5 elements are used as actuators, with 1 as disturbance source, and other 4 as active dampers. On the other side of a plate 4 elements are placed acting as vibration sensors. The actuator used as a disturbance source as well as sensors are always in the shape of a square. 4 modes were taken into account (analyzed each one singular and all together). Analyses were made with the use of ANSYS software.
9
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The Effect of Material Composition of Piezoelectric Elements with Chosen Shapes on Plate Vibration Reduction

100%
Wiciak J., Trojanowski R.
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vol. 125
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issue 4A
A-179-A-182
EN
This paper presents numerical analysis of efficiency of different shapes and material composition of piezoelectric actuators used for vibration reduction. Four numerical models representing a plate clamped on all sides with two attached piezoelectric elements were created. For each model, one element had the same shape and composition and was used for plate excitation, and the other one, used for vibration reduction, had different shape and possibly material composition and could be of square or circular shape with either homogeneous or two-part material composition. Two modes were taken into account: the first mode and the fifth mode. Analysis of results was performed with ANSYS software.
10
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Comparison of Vibration and Acoustic Pressure Reduction Using Different Types of Piezo actuators

100%
Wiciak J., Trojanowski R.
Acta Physica Polonica A
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2015
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vol. 128
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issue 1A
A-62-A-66
EN
This paper presents results of numerical simulations on reduction of sound pressure radiated from a square plate using different types of piezo actuators. For this purpose a FEM model was developed using ANSYS software with said steel plate with a hemisphere of air on one side of the plate. There are two criteria by which the reduction is measured: minimising vibrations of plate area and minimising sound pressure on a half sphere surrounding the plate. Changes in the results for both the radiated sound pressure and plate vibration are discussed.
11
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Preliminary Results of Laboratory Tested System for Active Control of Plates VIA LabVIEW and Piezoelectric Elements

100%
Trojanowski R., Wiciak J.
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issue 1
168-173
EN
The design and implementation of a labview and PID controller developed for the damping of sinusoidally excited forced vibrations of a plate is presented. The plate used in the study is clamped at one side and free at the others aluminum plate with five piezo elements attached. Two of them act as sensors, and three as actuators (one for vibration source, and two for active vibration control). Selected experimental results are used to demonstrate the effectiveness of the proposed platform.
12
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Choosing of Optimal Voltage Amplitude of Four Pairs Square Piezoelectric Elements for Minimization οf Acoustic Radiation of Vibrating Plate

100%
Kozień M., Wiciak J.
Acta Physica Polonica A
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2009
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vol. 116
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issue 3
348-350
EN
The study is a next part of earlier works by the authors, and explores how does the sequence of activated actuators and the level of applied voltage affect the radiated acoustic energy. The analysis uses the finite element method for structural vibrations and combination of the finite element and the intensity hybrid method to assess the level of sound radiation. The vibrating element is a steel plate with glued on actuators, supported on one edge and excited by a harmonically variable, concentrated load with a constant amplitude value.
13
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The Concept of a System for Identification of the Dangerous Areas for People with Visual Dysfunction

100%
Wiciak J., Borkowski B.
Acta Physica Polonica A
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2011
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vol. 119
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issue 6A
921-924
EN
The article presents the concept of a system for identification of dangerous areas in the urban area targeted at the people with visual dysfunction. The idea of the system is presented comprising the attempt of application of the wireless data transmission: IR - infra-red; BLUETOOTH; RFID. The consideration comprises also the identification of the object (human), identification of the movement direction (double barrier), wireless data transmission with data on the given dangerous area, excitation of the vibration information and the feedback of the system. Also the subject of optimal installation on the urban objects was discussed. The article is a realisation of the research task in the project called "The development of the method for marking of the dangerous areas and especially important places in urban area for visually impaired people with use of the wave-vibration markers".
14
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Passive Structural Acoustic Control of the Smart Plate - FEM Simulation

100%
Kozień M., Wiciak J.
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issue 6
1186-1188
EN
Finite element simulations of passive damped system applied to the simply-supported excited squared steel plate, is the aim of the analysis. The full mechanical, piezoelectric, electric and acoustic field coupling is analysed in Ansys Package. As the result the acoustic pressure radiated by plate is analysed. The results show possibility of application of the discussed method to reduction of the sound pressure level in realistic engineering structures.
15
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The Influence of the Measurement Chain on the Impulse Response of a Reverberation Room and Its Application Listening Tests

81%
Małecki P., Zastawnik M., Wiciak J., Kamisiński T.
Acta Physica Polonica A
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2011
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vol. 119
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issue 6A
1027-1030
EN
There are many objective parameters of the room impulse response which we can calculate that describe its acoustic field. The room impulse response can also be used to provide listening tests using the convolution technique. The aim of this work is to consider the influence of the impulse response measurement chain on objective numerical parameters and on the subjective perception of listeners. This article shows the impulse response measurement results obtained in the reverberation room using not only commonly known measurement chain elements but other elements, too. Standard components such as an omni-directional source and measurement microphone, as well as a consumer active loudspeaker and various audio recording stereo microphone pairs were used. The results are compared taking into consideration calculated numerical parameters and the application of calculated impulse responses to subjective listening tests. To determine the applicability of impulse responses to psychoacoustic listening tests, a preliminary listening test using headphones was carried out on a selected group of listeners. The audio test material consisted of samples of choral music and speech recorded in an anechoic room and convolved with previously analyzed impulse responses. This article shows how big the differences of subjective listener feelings are for different acoustic transducers.
16
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A System for Determination of Areas Hazardous for Blind People Using Wave-vibration Markers - Final Conclusions and Technical Application

81%
Wiciak J., Borkowski B., Czopek D.
Acta Physica Polonica A
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2013
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vol. 123
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issue 6
1101-1105
EN
The paper constitutes a summary of the work carried out under the research project entitled The development of the method for marking and identification of the spots dangerous and of special importance for vision impaired persons in the big city with use of the wave-vibration markers. This article discusses key researches conducted during the project, including review of influence of environmental sounds on orientation and mobility of blind and partially sighted people, results of vibration perception threshold measurement taken at the wrist of both hands, measurements of paraseismic vibrations and results of researches on annoyance, recognizability and easiness to learn of selected signals.
17
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Localization of the Sound Source with the Use of the First-order Ambisconic Microphone

81%
Wierzbicki J., Małecki P., Wiciak J.
Acta Physica Polonica A
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2013
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vol. 123
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issue 6
1114-1117
EN
The paper presents results of determination of sound wave direction based on signals from first-order ambisonic microphone. The experiment consisted in recording the test signals with the SoundField microphone positioned in the axis of the turntable in the anechoic chamber. The spherical coordinates of the sound intensity vector were calculated with use of three different conceptual and numerical approaches and were compared to actual values resulting from the geometry of the system. Accuracy of the localization of the sound source depending on the frequencies and the method for determination of the spherical coordinates as well as on the time constant and the parameters of the signal recording was presented. The obtained results show the effectiveness of the calculation methods used for localization of the sound source.
18
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Prototype System for Marking and Identification οf Dangerous Spots for Vision Impaired People - Size and Shape Testing Marking the Dangerous Spots Zone

81%
Wiciak J., Borkowski B., Czajka I.
Acta Physica Polonica A
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2012
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vol. 121
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issue 1A
A-24-A-27
EN
The article constitutes the continuation of the works realized under the research project entitled: "The development of the method for marking and identification of the spots dangerous and of special importance for vision impaired persons in the big city with use of the wave-vibration markers". The consideration included the identification of the object (human), identification of the direction of movement (double barrier), wireless data transmission with the information on the dangerous area, stimulation of the vibration signal and the feedback of the system. This article presents the result of choice of the optimal solution regarding the installation of the system on the selected objects of the urban engineering and also presents the concept of the method of modelling of the shape of the zone that is used for marking of the dangerous spot.
19
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The Effect of Wind Turbine Infrasound Emission on Subjectively Rated Activation Level

81%
Kasprzak C., Skrodzka E., Wiciak J.
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vol. 125
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issue 4A
A-45-A-48
EN
The problem of low-frequency acoustic waves emitted by wind turbine farms has become a great challenge to acousticians in Europe for more than 20 years. In Poland wind farm industry is growing rapidly and generates questions about the influence of such sounds on human organism. A short survey of previously published reports concerning subjectively perceived influence of wind turbines on people living next to wind farms is given together with the results of the Thayer's test measuring the difference in activation level before and after exposition on infrasound wave generated by a wind turbine. Statistically significant increase of the High Activation Level representing a tension type arousal has been revealed.
20
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Subjective Assessment of the Multi-Channel Auralizations

81%
Małecki P., Wiciak J., Wierzbicki J.
Acta Physica Polonica A
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2012
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vol. 121
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issue 1A
A-110-A-114
EN
The article presents the course and the results of an experiment, which aimed at the subjective assessment of the multi-channel impulse responses. The assessment was conducted considering the usefulness of the received responses for the conducting operation of the digital convolution. The resulting sound material is generated for the simulation of the characteristics of the room. In a medium-sized, rectangular reverberation room (74 m^3) a number of measurements of impulse responses were conducted with the use of multi-channel microphone techniques and with the use of SoundField type microphone. In identical conditions the raw sound material was recorded (in conditions of free field). Next, the convolution was performed between the raw material and the recorded impulse responses. The group of experts, whose members had at least 5 years of experience in the field of sound engineering, was subjected to the psychoacoustic tests aiming at comparison of the sound materials achieved in the convolution and in the recording.
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