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Sustainable Systems - a New Field for Vibroacoustics : Sustainable Vibroacoustics

Panuszka R.

Molecular and Quantum Acoustics

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2006

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Vol. 27

189-200

EN

The role of vibroacoustics is discussed. The author is trying to define a role of vibroacoustics at this stage of development of technology and human rights. The role of this research and education needs to be redefined on saving all three elements of global environment. This will equitably meet the biophysical needs of society as a whole, individual members plus maintaining the integrity of life-supporting ecosystems over a long-term time period. Traditional issues of vibroacoustics are under extensive development will need to be redirect into new visions which are now being discussed and developed.

2

Experimental assessment of coupling loss factors of thin rectangular plates

Panuszka R., Wiciak J., Iwaniec M.

Archives of Acoustics

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2005

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Vol. 30, No. 4

533-551

EN

Knowledge of Coupling Loss Factors (CLF's) for energy flow evaluation in structural elements of complex mechanical systems is fundamental. Several experiments were conducted to evaluate CLFs of different perpendicular connections of rectangular plates. The method of energy storage was conducted under acoustic free-field conditions, and a large number of thin plates with different designs of junctions were examined. The tests included two types of connections: welded line junction and point junctions. In the first type of connection, the influence of the thickness ratio of plates on CLFs values was tested. In the second type of connection the influence of the point of distribution at junctions on CLFs values were tested. Other tests were done to establish the impact of junction design on CLFs. Welded line junctions have a tendency to decrease the CLFs when the ratio of thickness of plates is increased. The CLFs also increase with density of joining points. Maximal values of CLFs were observed for spot-welded junctions. Mid-values were represented by screw-bolted joints and the lowest values by riveted junctions.

3

Acoustical Properties Modelling of the Souble Ptfe System by the Use Od Sea Method

Iwaniec M., Panuszka R., Wiciak J., Geissler P.

Molecular and Quantum Acoustics

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2002

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Vol. 23

175-186

EN

The recent yoears have whitnessed a rapid developement of new construcion materials, some of these showing anisotropic properties, while the constructions are light and very strong. These new materials appeared in the last few years, hence it is necessary to determine the acoustical parameters of such constructions. This study is concered with calculations of sound reduction index of three-layered systems made from thin, transparent polyurethane foil. Experimental tests were run for created numerical models and experimental results are compared with numerical calculations.

4

Predieting sound pressure levels on a cruise ship

Iwaniec M., Panuszka R., Wiciak J.

Hydroacoustics

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2001

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Vol. 4

95--100

EN

Advanced computer programs allowing for numerical solving of mechanical problems are often used as design tools. Effective use of packages based on the finite element method allows for predicting the dynamical behaviour of the structure already at the design stage. This study is concerned with numerical analysis of the hull in a passenger ship whose FEM model is based on the technical specifications. Estimated values of acoustic pressure are compared with measurement results. Furthermore, the applicability of computer models to predictions of dynamic behaviour of complex structures is evaluated.

5

Prediction of acoustic stresses in panel aircraft constructions with application of energy models

Niepokólczycki A., Panuszka R.

Prace Instytutu Lotnictwa

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2000

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Nr 3-4 (162-163)

65-69

EN

Paper presents method of prediction od dynamic stresses in stochastically vibrating structures. This method links the Finite Element Method, considered as a tool for analysing vibrations, with the Statistical Energy Analysis Method, considered as a tool for analysing the interactions between vibrating structure and adjacent sound field. Using presented method, constructor can determine at the design stage the stress distribution in a structure and predict acoustic fatique life of the structure.

PL

W pracy przedstawiono metodę prognozowania naprężeń dynamicznych w drgających stochastycznie strukturach. Metoda ta jest połączeniem Metody Elementów Skończonych jako narzędzia analizy drgań struktury z Metodą Statystycznej Analizy Energii jako narzędzia analizy oddziaływań pomiędzy drgającą strukturą i otoczeniem. Dzięki prezentowanej metodzie możliwe jest określenie naprężeń dynamicznych w drgającej strukturze oraz jej trwałości akustycznej.

6

Current trends of the works on acoustics presented at the XLVI Open Seminar on Acoustics OSA'99

Panuszka R., Iwaniec M.

Archives of Acoustics

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2000

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Vol. 25, no. 1

111-123

EN

The XLVI Open Seminar on Acoustics was held in Zakopane from the 14th to the 17th of September 1999. It was organized by Cracow's Section of the Polish Acoustic Society, the Laboratory of Structural Acoustics and Intelligent Materials, the Faculty of Mechanical Engineering and Robotics of the Academy of Mining in Cracow and the Committee on Acoustics of the Polish Academy of Sciences. The number of participants was 175. 118 papers were presented. The honorary president was Prof. Ignacy Malecki. Prof. Zbigniew Engel was chairman of the Scientific Committee and the Organizing Committee was chaired by Prof. Ryszard Panuszka. The Seminar was opened by the plenary lecture of Prof. Ignacy Malecki devoted to the application of acoustic emission in engineering materials. The examples of new applications presented in his lecture concerned the monitoring of the technology of ceramics, the investigation of variations in the structure and microstructure of those materials caused by thermal shocks and the monitoring of the behaviour of constructions under conditions close to those prevailing during their long term exploitation as well as the analysis of mechanical and thermo-mechanical parameters in that plasticity and pseudoplasticity effects have been considered. At the beginning of the proceedings in each section a plenary lecture was given. All in all, seven lectures were delivered. Prof. Antoni Jaroszewski discussed the perception effects of an acoustic injury caused by exposure to music sounds with reference to loudness, height discrimination and the frequency and time resolution. Musicians are particularly subject to those injuries. Significant lasting, selective and high-frequency losses in their hearing were found. They indicate that the hearing protection of this group of people is insufficient. Prof. Eugeniusz Kozaczka focused his lecture on some problems of the non-linear effects connected with the generation and propagation of elastic waves in water, on non-linear properties of a medium as well as on making use of those properties in parametric sources of acoustic waves. Prof. Adam Lipowczan characterized the usefulness of modern GIS and GPS techniques in the solution of problems connected with the dangers of vibroacoustic effects to the environment. Those techniques, linking computer maps with data bases, offer new research methods and applications to the study of the propagation of noise and mechanical vibrations in the environment. Dr. Henryk Łopacz presented the possibility of the simulation of audio monitoring in physical as well as in virtual rooms. The simulation of audio monitoring conditions is realized by a convolution of pulse response for a given transmission way and the test signal. In the algorithms presented, the influence of room dimensions, the locations of transmitting and receiving points and the attenuating properties of the room can be taken into account. Profesor Stefan Weyna discussed the analysis of measurements of the vector effects of an acoustic wave represented as sound intensity in the acoustic field of real sources. The results presented concerned measurements of acoustic phenomena occurring in the near field and in small limited areas. The application of a broad-band three-way system to the identification and classification of sea fish shoals was presented by Professor Manell Zakharia. The main construction problems of this device concern the transducers, the levels of the transmitted and received signals, the directivity and impedance variations in the whole frequency region. For a correct working of the device, the algorithm of identification of the fish species is also essential. It was shown that neuron nets can be applied to this end. The device discussed is characterized by a high linearity and a better estimation of the fish size. The identification of the fish species is based only on the characteristic frequencies of the received echo.

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Particle Trajectories in Air-flow Around a Cylinder

Szopa G., Panuszka R.

Mechanika / Akademia Górniczo-Hutnicza im. St. Staszica

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1998

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T. 17, z. 1

147-161

EN

Dispersed flows have a manifold occurence in practical applications. The interaction of these flows with obstructions like a cylinder have a big influence on heat transfer, dynamie fluctuations, corrosion process and so on. Aims research was the measuring of the trajectories of solid particles with a diameter of (1.5-3.0) o 1CT3 m in downward gaś flow near a solid cylinder with diameter of 25 1CT3 m and the comparison of the trajectories with Fidap computed trajectories to predict phenomenon. The measumerents still play primary roles in visualizing unknown flow behavior in as complicated system as a dispersed-phase flow pat a obstacle, because a complete theoretical even numerical modeling does not exists. This work showes one of the methods of measurement of the trajectories by means of photographic technique.

PL

Dyspersyjne przepływy występują w różnorodnych praktycznych zastosowaniach. Wzajemne oddziaływanie tych przepływów z przeszkodami, takimi jak cylinder, ma duży wpływ na takie procesy jak: wymiana ciepła, dynamiczna fluktuacja, korozja itd. Celem niniejszej pracy badawczej były pomiary trajektorii cząsteczek o średnicy od 1,5 10~3 do 3,0 o 1CT3 m w skierowanym w dół przepływie gazowym w pobliżu cylindra o średnicy 25 1CT3 m, a także porównanie zmierzonych trajektorii z obliczonymi trajektoriami w Fida-pie dia dalszej prognozy zjawiska. Pomiary trajektorii wciąż odgrywają pierwszoplanową rolę w wizualizacji nieznanego przepływu w tak skomplikowanym systemie jakim jest dyspersyjnie-fazowy przepływ w pobliżu przeszkody. Wynika to z faktu, że kompletne teoretyczne a nawet numeryczne zamodelowanie zjawiska nie jest możliwe. Obecna praca przedstawia jeden ze sposobów wyznaczenia trajektorii z zastosowaniem techniki fotograficznej.

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Modelowanie układów ciągłych z wibroizolacją przy użyciu programu VibraCAD

Stefanik P., Panuszka R.

Mechanika / Akademia Górniczo-Hutnicza im. St. Staszica

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1998

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T. 17, z. 1

133-145

PL

W pracy przedstawiono podstawy teoretyczne metody mobilności służącej do analizy dynamiki układów dyskretnych i układów o ciągłym rozkładzie masy z wibroizolacją. Podano charakterystykę programu komputerowego VibraCAD o algorytmach obliczeniowych opartych na metodzie mobilnościowej. Praca zawiera przykład analizy drgań układu belkowego z wibroizolacją wykonanej przy użyciu programu VibraCAD.

EN

Paper presents the theory of mobility method which can be used for analysis of the discrete and continous systems with vibroisolation. The characteristic of the VibraCAD program is presented with calculations algorithms based on mobility method. The example of the analysis of the vibrations of the beam system with vibroisolation is described where VibraCAD program were used.