PSI - Issue 27

Tuswan Tuswan et al. / Procedia Structural Integrity 27 (2020) 22–29 Tuswan et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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In the lowest mode, the natural frequencies are also affected by imperfection but not as sensitive as higher modes. Several investigations also show that damage detection in the sandwich plate is more sensitive in higher modes (Lou et al., 2014; Lu et al., 2017; Ismail et al., 2020). Changes in natural frequency occur due to local deformation around

140

Initial Square

130

Trough-the-Length Trough-the-Width Circular

120

110

100

90

Natural frequency (Hz)

80

6

7

8

9

10

Mode Number

(a)

(b)

Fig. 4. Natural frequencies of intact and debonding models with spring contact element with different debonding shapes (a) mode number 1-5, and (b) mode number 6-10.

160

10 20 30 40 50 60 70 80

Initial Square

Initial Square

140

Trough-the-Length Trough-the-Width Circular

Trough-the-Length Trough-the-Width Circular

120

100

80

60

Natural frequency (Hz)

Natural frequency (Hz)

40

1

2

3

4

5

6

7

8

9

10

Mode Number

Mode Number

(a)

(b)

Fig. 5. Natural frequencies of intact and debonding models without spring contact element with different debonding shapes (a) mode number 1-5, and (b) mode number 6-10.

10 12 14 16 18

0 10 20 30 40 50 60 70 80

Trough-the-Length Trough-the-Width Circular Square

Trough-the-Length Trough-the-Width Circular Square

0 2 4 6 8

Natural Frequency (Hz)

Natural Frequency (Hz)

1 2 3 4 5 6 7 8 9 10

1 2 3 4 5 6 7 8 9 10

Mode Number

Mode Number

(a)

(b)

Fig. 6. Natural frequency shift of debonding models with different debonding shapes (a) with spring element, and (b) without spring element.