Razvoj modela odlučivanja za izbor optimalne smeše zvučno apsorpcionih materijala

Abstract

Buka je poslednjih decenija jedan od osnovnih uzroka kompleksnog oštećenja zdravlja stanovništva, posebno u industrijski razvijenim zemljama. Sve veći obim industrijske proizvodnje, sve brojnije i brže saobraćajne veze i sve šira primena mašina i uređaja u komunalnoj sredini, kao i mnogi drugi faktori koji ljudima omogućuju udobniji život, istovremeno dovode i do svoje negacije koja se ispoljava u obliku ozbiljnog ugrožavanja čovekovog zdravlja. Borba protiv buke i njenog štetnog dejstva deo su napora koji se čine za poboljšanje uslova života i za zaštitu životne i radne sredine naročito u gusto naseljenim područjima. Jedan od načina za smanjenje nivoa buke je primena apsorpcionih materijala koji apsorbuju deo energije zvuka i karakterišu se koeficijentom apsorpcije kao frekvencijski zavisnom veličinom. Osim potrebe da se apsorbuju različiti delovi frekvencijskog oktavnog spektra koju daju različiti izvori buke pri izboru apsorpcionih materijala treba voditi računa i o drugim neakustičkim zahtevima kao što su: izgled, životni vek, bezbednost, mogućnost održavanja, mogućnost korišćenja recikliranih otpadnih materijala, cena, mogućnost ponovne reciklaže nakon isteka perioda korišćenja i dr. U radu je formiran Model odlučivanja za izbor optimalne varijante zvučno apsorpcionih materijala i njihovih smeša koji se mogu koristiti za zaštitu od buke, bilo da je u pitanju rešenje problema buke u industrijskim pogonima, koncertnim dvoranama ili na otvorenom prostoru pored drumskih i železničkih saobraćajnica. Model se zasniva na višekriterijumskom odlučivanju u kome su alternative rangirane prema akustičkim i neakustičkim parametrima. Pošto se zvučno apsorpcioni materijali koriste za zaštitu od buke u životnoj sredini, kriterijumi za njihov izbor koji se odnose na bezbednost i zdravlje ljudi imaju apsolutni prioritet, tako što su eliminatorni za materijale koji ih ne ispunjavaju. Na konkretnom primeru zaštite od saobraćajne buke, odabrana je i implementirana optimalna alternativa za izbor apsorpcionog materijala za izradu zvučne barijere, uzimajući u obzir karakteristike buke na mestima izvora i barijere. Višekriterijumska optimizacija je retko zastupljena u naučnoj literaturi kao metoda za izbor optimalnog rešenja apsorpcionih materijala i njihovih smeša. Osnovni problem je nemogućnost generisanja velikog broja pouzdanih alternativa na osnovu akustičkih zahteva. U cilju rešavanja navedenog problema, u radu su razvijeni algoritmi za formiranje makroskopskih empirijskih modela i stohastičkih modela poroznih materijala. Merenje koeficijenta apsorpcije je izvršeno prema metoda SRPS EN ISO 10534-2. Za određivanje podužne otpornosti strujanju vazduha isprojektovan je i realizovan merni sistem sa konstantnim protokom vazduha prema metodi SRPS ISO 9053. Predložena je nova metoda za određivanje podužne otpornosti strujanju vazduha, čije se predviđanje u odnosu na standardnu metodu razlikuje za 1.8%, što je manje od dozvoljene vrednosti od 15% iz naučne literature.

In the last few decades, noise is one of the main causes of the population health damage, especially in industrialized countries. An increasing volume of industrial production, greater and faster traffic and a broader application of the machinery and equipment in the communal area, as well as many other factors that enable more comfortable life to us, leads to its negation, which is manifested in the form of a serious threat to human health. The fight against noise and its harmful effects are part of the efforts which are made in order to improve living conditions and to protect the living and working environment, especially in densely populated areas. One way to reduce the noise level is the use of the absorbing materials which absorb some parts of the sound energy and which are characterized by the coefficient of absorption as a frequency - dependent variable. Besides the need for the absorption of different parts of the frequency octave spectrum which are produced by different sources of noise, there are some non-acoustic requirements which should be taken care of, such as: appearance, service life, safety, maintainability, the possibility of using recycled waste materials, cost, possibility of repeated recycling after the expiry date, etc. The dissertation presents the development of a decision-making model for the selection of the optimal variant of sound absorbing materials and their mixtures which can be used for noise protection, thus solving possible noise problems in industrial plants, concert halls or in an open space by the roads and railway lines. The model is based on multi-criteria decision-making in which the alternatives are ranked according to acoustic and non-acoustic parameters. As sound absorbing materials are used for noise protection in the environment, the criteria for their selection which refer to safety and health of people are an absolute priority, and hence they are eliminatory for the materials which do not fulfil them. In a concrete example of traffic noise protection, the optimum alternative for the selection of absorbing material for production of a noise barrier was chosen and implemented, taking into account the characteristics of noise at the points of its source and the barrier. Multi-criteria optimization is rarely present in the scientific literature as a method for the selection of the optimum solution of absorbing materials and their mixtures. The main problem is in the impossibility of generating a large number of reliable alternatives based on acoustic requirements. For the purpose of solving the mentioned problem, the dissertation presents the development of algorithms for creating empirical macroscopic models and stochastic models of porous materials. The measurement of absorption coefficients was performed according to the method SRPS EN ISO 10534-2. In order to determine airflow resistivity, a measurement system with constant airflow was designed and realized according to the method SRPS ISO 9053. A new method for determination of airflow resistivity whose prediction differs from the standard method by 1.8%, which is less than the allowed value of 15% from the scientific literature, was proposed.