Objective

To identiy noise sources on a transaxle for constant speeds as well as speed sweeps.

Test Procedure

1. A 63-microphone array was used to capture acoustic pressure data close to the transaxle surface.
2. Stationary data was captured for 6 seconds. Non-stationary data was captured for the duration of the sweep.
3. Acoustic pressure, normal acoustic intensity and surface velocity were reconstructed on the transaxle surface.

Results

The following images shows the measured sound pressure spectra that clearly show a peak at 1250 Hz.

The following three screenshots show the reconstructed SPL, normal acoustic intensity and surface velocity distribution respectively at 1250Hz on the side surface.

The following image shows the RPM-Frequency-SPL spectrogram for a speed sweep. The image on the right shows the reconstructed normal acoustic intensity distribution at 2960 rpm, 1380 Hz, 31st order on the front surface.

Normal Acoustic intensity