Damping foils are the most widely used damping treatment to control vibrations of structures subjected to dynamic loads. Damping treatment requires the selection of appropriate damping material, locations of the treatment, and choice of configurations which ensure the transfer of deformations from the structure to the damping elements. In the current work, the effect of 3M-2552 damping tapes in various configurations are analyzed to minimize the modal response of a rectangular plate by optimizing its placements.

Random excitation test was used to compute the modal parameters and details of the experimental setup are shown in figure 2. Dytran accelerometer of sensitivity 10 mV/g is used to acquire the plate response to random vibration generated through an arbitrary signal generator. A PCB force transducer is used to acquire the input force. A 25 kgf electrodynamic shaker from MB Dynamics is used to excite the structure. Data acquisition is done through a 24 channel, 32 bit Heim module through ME Scope 5.1

Responses are collected at 12 points as shown in figure 3 and the FRF’s are built and used to compute the frequencies, damping and mode shapes for the first 3 modes of the plate constrained as a cantilever. The constrained end is subjected to high strain and free end will have maximum displacement which is typical expected behavior of a cantilever plate.

The damping foil is made into strips of size 50x80mm and is attached to the plate in 2 different configurations. The first configuration is at maximum strain location and second is at maximum displacement location as shown in shown in Figure 4.

Experimentally obtained mode shapes of the plate are shown in Figure 5.

The Frequency Response Functions for the two damping foil configurations are shown in Figure 6.

The results are summarized in Table 1 (Baseline), 2 (Configuration 1) and 3 (Configuration 2) respectively.

Table 1 FRF for Baseline

Table 2 FRF for Configuration 1

Table 3 FRF for Configuration 2

It is clearly evident that CLD tapes are very effective and efficient when placed at maximum strain regions for a particular mode, compared to other regions. Strain energy is utilized at the viscoelastic layer and converted into negligible heat. On a contrary, it is to be noted that the performance is not optimum if the foils are placed at inappropriate locations.