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SDS Self Adhesive Dampers
Measurements of 2 mm aluminium plate with and without 0.5 AliDamp.
David Thompson, ISVR, University of Southampton.
Two aluminium plates were supplied, each 2 mm thick and 1.0´0.8 m. One was untreated, the other had with 0.5 AliDamp bonded to it. Measurements of both were taken using an instrumented impact hammer and an accelerometer, with the plates freely suspended. The measurement results correspond to the spatially-averaged vibration due to a unit force at a fixed position. The difference in spatially-averaged vibration level is directly equivalent to a difference in noise level.
Figure 1 shows the vibration velocity levels on the two plates for a unit force in one-third octave frequency bands. Figure 2 shows the same results in octave bands.
From these results it can be seen that the damping treatment has produced a reduction in vibration of more than 20 dB at most frequencies. The corresponding noise reduction would be identical to the difference.
It is also possible from these results to determine the damping loss factor of the plates. This is actually more meaningful than the noise reduction, as untreated panels usually have higher damping when mounted in situ than when freely suspended as here. The loss factors are shown in Figure 3. The loss factor of the treated panel is between 0.1 and 0.2 at most frequencies.
Professor David Thompson, 23 December 2003
Blue = treated, red = untreated
