Abstract
The aim of the study was to identify acoustic and structural modes in the
spectrum obtained exper-imentally inside an operator's cab in a bulldozer.
Measurements were taken inside the operator's cab in a caterpillar-track
bulldozer Polremaco TD12NPH2E-2000, designed for work in underground mine
enclosures. The acoustic pressure spectrum was obtained for varied
rotational speeds of the engine during the free run of the machine. The
reverberation time of the cab was determined basing on the pulse-type
excited pressure response, followed by identification of the spectral
components registered by measurements. Thus, identified frequencies were
compared with natural acoustic frequencies registered inside the
operator's cab and with frequencies associated with the valves and
ignition frequencies due to rotational speed and natural frequencies of
structural vibrations of the cab's walls. This study was conducted in an
attempt to reduce the noise inside the operator's cab using passive methods
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