master's thesis
Automated Noise Level Measurement in Engineering Materials

Dario Pović (2015)
Metadata
TitleAutomatizirano mjerenje buke u inženjerskim materijalima
AuthorDario Pović
Mentor(s)Tomislav Keser (thesis advisor)
Abstract
Buku možemo definirati kao neželjeni zvuk. Razinu buke izražavamo mjernom jedinicom Bel [B] koja označava odnos razine zvučnog tlaka ili odnos amplitude napona. Češće se koristi mjerna jedinica decibel [dB] koja predstavlja jednu desetinu jedinice Bel. 80% ukupne buke u gradovima uzrokuju vozila na motorni pogon (automobili, kamioni, motocikli, vlakovi, avioni…). Osim što stvara nelagodu kod ljudi, buka može biti uzročnik brojnih zdravstvenih problema. Buka nastala u prometu skup je zvukova nastalih kao posljedica rada vozila ili interakcije vozila i okoline. Na razinu emitirane buke još može utjecati vrsta pneumatika i opterećenje samog vozila, stanje kolnika (fizička oštećenja kolnika i hrapavost kolničkog pokrova), vremenski uvjeti (npr. kiša) te vrsta kolničkog pokrova (asfalt, beton…). Najprikladnije rješenje za sanaciju povišene razine buke zasigurno je uporaba mjera smanjenja buke na mjestu nastanka same buke. Ukoliko navedene mjere nisu dovoljne idući korak je utjecaj na buku koja nastaje izvan vozila. U ovom slučaju glavni uzročnik nastanka ovakve vrste buke je interakcija pneumatika i vozne podloge. Ukoliko zanemarimo samu gumu u procesu nastanka buke, preostaje nam vozna podloga sa svojim karakteristikama. Istraživanja su pokazala kako je odabir materijal za izradu kolnika bitna stavka koja utječe na razinu emitirane buke. Vozna podloga je nekoliko puta tvrđa od automobilske gume te se prilikom rotacije kotača stvaraju vibracije. Rezultat nastalih vibracija je buka koja se širi okolnim prostorom. Poroznost ili šupljikavost je svojstvo materijala da u svojoj strukturi sadrži malene pukotine koje su ispunjene zrakom. Posljedica veće poroznosti materijala je smanjenje količine istisnutog zraka nastale pri gibanju kotača po voznoj podlozi čime većina nastalih vibracije ostaju u voznoj podlozi. Iako se u prošlosti problemu buke nije posvećivalo previše pozornosti, u današnje vrijeme se ide korak dalje. Težnja je razinu buke svesti na prihvatljivu vrijednost već u fazi projektiranja prometnica čime se pojavila potreba za razvojem postupaka projektiranja, izrade i ispitivanja novih inženjerskih materijala koji imaju svojstvo upijanja ili refleksije buke. U tu svrhu je nastao i ovaj diplomski rad čiji je cilj projektirati, izraditi i optimirati samodostatni sustav temeljen na PC platformi u Matlab okruženju za automatizirano mjerenje upojnosti i reflektivnosti buke u inženjerskim materijalima čime bi se ubrzao postupak ispitivanja testiranih uzoraka
Keywordsabsorption noise porosity reflectivity
Parallel title (English)Automated Noise Level Measurement in Engineering Materials
Committee MembersTomislav Keser (committee chairperson)
Alfonzo Baumgartner (committee member)
Ivan Aleksi (committee member)
GranterSveučilište Josipa Jurja Strossmayera u Osijeku
Fakultet elektrotehnike, računarstva i informacijskih tehnologija Osijek
Lower level organizational unitsZavod za računalno inženjerstvo i automatiku
Katedra za računalno inženjerstvo
PlaceOsijek
StateCroatia
Scientific field, discipline, subdisciplineTECHNICAL SCIENCES
Computing
Program Engineering
Study programme typeuniversity
Study levelgraduate
Study programmeGraduate University Study Programme in Computer Engineering
Academic title abbreviationmag.ing.comp.
Genremaster's thesis
Language Croatian
Defense date2015-10-01
Parallel abstract (English)
Noise can be defined as unwanted sound.The noise level is represented with measurement unit Bel [B], which indicates the ratio of sound pressure levels or the ratio of voltage amplitude. More commonly used measurement unit is decibel [dB], which represents one-tenth of the unit Bel. 80% of noise in cities is caused by motor vehicles (cars, trucks, motorcycles, trains, planes ...). In addition of being a source of discomfort in humans, the noise may be the cause of many health problems. The noise generated by traffic is made up of sounds that are formed as a result of operation of vehicle or as a result of the interactions between vehicles and environment. The level of noise can be also affect depending on tire types and load of the vehicle itself, the physical condition of the pavement (physical damage of road and roughness of road surface), weather conditions (eg, rain) and the type of road surface (asphalt, concrete ...). The most appropriate solution for reducing the higher noise level is certainly the use of measures to reduce noise at source of noise origin. If these measures are not sufficient the next step is the impact on noise that is generated all around the vehicle. The main source of this type of noise is the interaction of tire and road surfaces. If we ignore the role of tires in the process of making noise, all that remains is the driving surface with its own characteristics. Studies have shown that the choice of material for making pavement is the key feature that affects the level of emitted noise. Driving surface is several times harder than the tires and that is why the vibrations are generated during the rotation of the wheel. The effect of the resulting vibrations is the noise that propagates the surrounding area. Porosity is a property of the material which in its structure contains small cracks that are filled with air. The consequence of higher porosity is manifested in reduction of the displaced air generated by the movement of the wheels on the driving surface after which most of the generated vibrations remains in the driving surface. Although in the past to the problem of noise has not been paid much attention, today we go one step further.In the past, the problem of noise has not been paid much attention, but today we go one step further. Today's goal is to bring noise levels to an acceptable value already in the road design phase which led to an increased need for methods of designing, manufacturing and testing of new engineering materials which have properties of absorption or reflection noise. Therefore, this work was created with the aim to design, develop and optimize self-sufficient system based on PC platform in the Matlab environment for the automated measurement of absorption and reflectivity of noise in engineering materials, helping to accelerate the process of sample testing.
Parallel keywords (Croatian)buka poroznost reflektivnost upojnost
Resource typetext
Access conditionOpen access
Terms of usehttp://rightsstatements.org/vocab/InC/1.0/
URN:NBNhttps://urn.nsk.hr/urn:nbn:hr:200:844999
CommitterAnka Ovničević