PSI - Issue 5

J. Morais et al. / Procedia Structural Integrity 5 (2017) 705–712

710

Morais J et al./ Structural Integrity Procedia 00 (2017) 000 – 000

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Table 1 shows the set of parameters used for each series of tests. Each series was performed with three repetitions and an average of 10 cycles per repetition, at room temperature (average 22.5 ºC). The table also shows the average measured strain-rate for each test series.

Table 1: set of parameters used in each test series.

Test Frequency (Hz)

Test Amplitude (peak to peak) (mm)

Average Strain-Rate (%/s)

0,05 0,05 0,05 0,05

6 8

0,16 0,21 0,27 0,33 0,32 0,43 0,54 0,64 1,59 2,13 2,69 3,22 3,21 4,29 5,37 6,42

10 12

0,1 0,1 0,1 0,1 0,5 0,5 0,5 0,5

6 8

10 12

6 8

10 12

1 1 1 1

6 8

10 12

4. Results

The main goal of these tests was to validate the proposed damper configuration, in terms of its mechanical performance as well as its proficiency as a damping device. Mechanically the device behaved according to expectations, provided that it is adequately lubricated and properly aligned with the press clamps. To determine its performance as a damping device, the obtained results were analyzed and compared to ultimately calculate the equivalent viscous damping ratio ( ξ ) of the device, according to formulae (1) [Dolce et al. (2000)], where E D is the energy dissipated in each loading cycle and E S is the maximum strain energy.

E E

4 1 



S D

(1)



Fig. 7 illustrates the mechanical behaviour of the device as a function of the applied displacement amplitude and cyclic frequency by comparing different test series. The first graphic shows that the resulting load is highly dependent on the applied displacement amplitude, while the second graphic illustrates that the device has lower sensitivity to frequency changes.