REDUCING SOUND POWER LEVELS AT ISOLATED FREQUENCIES WITH STRATEGICALLY PLACED CONSTRAINED LAYER DAMPING PATCHES

摘要

Overall the results from the vacuum shell confirm that the method for determining patch locationworks. This method is not an absolute method for determining optimum patch location, there is stillsome trial and error involved. One other idea these results confirm is that one can use acousticintensity to identify the vibration pattern and therefore guide the placement of damping patches.The results from the washing machine definitely show the potency of this method of choosingdamping patch locations. With one of the damping configurations there was 8.2 dB reduction at 120Hz and 8.6 dB reduction at 240 Hz. This was done with less than 5% of the washing machine shell’ssurface area covered with damping material. This is a large amount of reduction for such a smallamount of damping material. While the method did guide the effective placement of dampingpatches, trial and error was still required to optimize the placement. Therefore, the method provides avery good tool to start the optimization process.