COBEM99

S20 Vibroacústica

Title:

IDENTIFICATION, QUANTIFICATION AND SPECTRAL ANALYSIS OF THE SOURCES OF NOISE IN AGRICULTURAL TRACTORS

Summary :

INNUMERABLE SCIENTIFIC WORKS HAVE BEEN VERIFYING THE UNHEALTHINESS EXISTENCE FOR NOISE IN OPERATIONS WITH AGRICULTURAL TRACTORS. WHILE IT IS KNOWN THAT ABOVE LEVELS OF NOISE OF 80 DB(A) FOR EXPOSITIONS OF 8 DAILY HOURS AUDITORY RISK ALREADY EXISTS, THOSE MACHINES EMIT NOISES ABOVE 95 DB(A). THE LARGEST PROBLEM FOR THE RESEARCHERS IS TO IDENTIFY THE NOISE SOURCES IN A TRACTOR AND TO QUANTIFY THE CONTRIBUTION OF EACH ONE IN THE TOTAL NOISE OF THE MACHINE. THIS WAY, THE OBJECTIVE OF THIS WORK IS THE COMPONENTS MECHANICS OF THE TRACTOR IDENTIFICATION THAT THEY GENERATE NOISE. THE METHODOLOGY EMPLOYED IN THE EVALUATION OF THE NOISE OF EACH SOURCE FOLLOWED THE FOLLOWING STEPS: IDENTIFICATION OF THE SOURCES, ISOLATION OF THE SOURCES, MENSURATION OF THE NOISE EMITTED BY EACH SOURCE AND SPECTRAL ANALYSIS OF THE MEASURED DATA. IN THE MENSURATION OF THE NOISE THE METHODOLOGIES FOLLOWED IN THE NORMAS ISO AND BRAZILIAN NORMS WERE USED, BEING EMPLOYED A SYSTEM ACQUISITION OF DATA (ANALOGICAL-DIGITAL PLATE INSTALLED IN A COMPUTER) FOR THE OBTAINING OF THE SPECTRUM OF FREQUENCIES. THE RESULTS SHOWED THAT THE TOTAL NOISE OF A TRACTOR IS FORMED BY THE COMPOSITION OF THE NOISES OF THE EXAUST OF THE GASES, NOISE OF THE PROPELLER, NOISE OF THE INJECT BOMB, NOISE OF THE FILTER OF AIR AND NOISE OF THE MECHANICAL VIBRATION OF THE MOTOR. THE QUANTIFICATION OF EACH NOISE PORTION IS PRESENTED IN SPECTRAL CURVES. AS CONCLUSION, IS POSSIBLE TO PERCEIVE THE IMPORTANCE OF THE IDENTIFICATION OF EACH SOURCE OF NOISE OF A TRACTOR, MAINLY WITH THE SPECTRAL ANALYSIS. THESE DATA PERMIT TO QUANTIFY THE FRACTIONS THAT FORM THE TOTAL NOISE, FACILITATING ENOUGH THE WORK OF ATTENUATION OF THE NOISE IN EACH SOURCE.

Author :

Bormio, Marcos Roberto 0
Fernandes, João Candido
Santos, João Eduardo Guarnetti
Santos Filho, Abilio Garcia dos

Paper View :