A new approach to the measurement of transverse vibration and acoustic radiation of automotive belts using laser Doppler vibrometry and acoustic intensity techniques

In previous work (Measurement Science & Technology, 11 (10) Oct 2000, pp.1463-72), it was shown that the noise radiated at meshing frequency by a belt drive can be estimated using vibration measurements taken by a scanning laser Doppler vibrometer as inputs for a boundary element model. The same approach is here extended to a more complex test bench where a real scheme of a belt drive is employed as an example of those currently present on automotive engines; an internal combustion engine cylinder head gives additional excitation. The test bench has been designed to reduce the noise radiation due to interfering sources (electric motor, cooling system, etc) and to make it possible to measure the noise contribution from the belt drive only. Reference noise measurements were performed by acoustic intensity techniques. The sound power values obtained from these measurements have been compared to those obtained from the boundary element model. The techniques employed in this work are shown to be capable of analysing resonance and meshing phenomena on a real belt drive geometry. (Original abstract - amended)