PSI - Issue 42

Iulian-Ionut AILINEI et al. / Procedia Structural Integrity 42 (2022) 1422–1427 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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4

4. Results and Discussions The main results from the experimental investigation are presented below. The frequency response functions for the runs made on each specimen are plotted for every cut orientation: 0°, 45° and 90°, respectively, in Fig. 4. One can observe that there is no significant difference between the frequency’s response function, the difference is in the amplitude.

0 1 10 100 1000

45 90 0

10

100

1000

Acceleration [m/s²]

Frequency (Hz)

Fig. 4. Frequency response functions

The average with the standard deviation for the 1 st and 2 nd frequency are presented in Fig. 5.a. First, we can observe that the first resonance frequency is almost the same for all directions; different values are shown for 2 nd resonance frequency. The value ranges from 738 Hz for the specimens cut at 45 ⁰ to 783 Hz for models cut at 90 ⁰ . The 1 st amplitude means presents the highest value for 45⁰ , 164 m/s 2 , and the lowest value for 0⁰ , 108 m/s 2 , likewise in the case of the 2 nd amplitude mean, the lowest value is presented for the 45⁰ , 62 m/s 2 , and the highest value for 0⁰ , 142 m/s 2 Fig. 5.b. D amping ratios are shown in Fig. 6 for each frequency mean. As can be seen, the highest values recorded for the specimens cut at 45⁰ for the 1 st and 2 nd frequencies represent.

100 150 200

0 250 500 750 1000

1st Resonance Frequency 2nd Resonance Frequency

773 738 783

0 50 Amplitude [m/s 2 ] b)

164

154

142

120

108

102 100

104

62

Frequency [Hz]

0°

45°

90°

a)

0°

45°

90°

Fig. 5. a) Resonance frequency, and b) Amplitude mean

0.0000 0.0025 0.0050 0.0075 0.0100

0.0000 0.0025 0.0050 0.0075 0.0100

0.00686

0.00586

0.00576

0.00513

0.00385

0.00308

Damping Ratio a)

Damping Ratio b)

0°

45°

90°

0°

45°

90°

Fig. 6. Damping correspondent a) to the 1st frequency mean, and b) to the 2nd frequency mean