PSI - Issue 12

V. Dattoma et al. / Procedia Structural Integrity 12 (2018) 9–18 Author name / Structural Integrity Procedia 00 (2018) 000 – 000

15

7

Table 6 and 7 summarizes the signal UT amplitude data detected with the various techniques and probes employed in this study.

Table 6. Principal defects results of Plate-1.

CONTACT UT

WATER STREAM UT

IMMERSION UT

Defect Dimension [mm]

Defect Depth [mm]

Probe 1 [%]

Probe 2,25 [%]

Probe 1÷ 6 [%]

Probe 1 [%]

Probe 2,25 [%]

Probe 1÷ 6 [%]

Probe 1 [%]

Probe 2,25 [%]

Probe 1÷ 6 [%]

5 5 5 5

1,9 3,4 4,2 4,2 1,4 2,4 3,4 4,2 1,9 4,2

102

102 35,2 44,4 102 102 58,8 102 40 52

98

102 60,8 92,4 61,2 102 102 102 67,2 102

102 73,2 77,6 68,4 102 85,2 81,2 102 76,8 86

92

102 102

102 102 102 102 102 102 102 102 102 102

102

44

40,8 39,2 48,8 102 87,2 102 69,9 102

55,6 45,2 39,2 76,4

64

42,4 60,8 102 102 102 76,4 102 80,4

96

39,6 46,8 102 102 102 58,4 102 71,6

98,8 102 102 102 102 87,2 92

10 10 10 10 20 20

72

61,2

46

102 48,4

66

76

74

Table 7. Principal defects results of Plate-2.

CONTACT UT

WATER STREAM UT

IMMERSION UT

Defect Dimension [mm]

Defect Depth [mm]

Probe 1 [%]

Probe 2,25 [%]

Probe 1÷ 6 [%]

Probe 1 [%]

Probe 2,25 [%]

Probe 1÷ 6 [%]

Probe 1 [%]

Probe 2,25 [%]

Probe 1÷ 6 [%]

4 4 4

2,8 5,6 8,4 2,8 8,4 8,4 5,6 5,6 8,4

76,4 30,8 18,4 102 32,8 32,8 60,4 73,6 35,6

65,2 34,4 29,2 92,8 40,4 48,4 50,4 35,2 32

50

64,4 32,4 20,8 102 34,4 24,8 56,4 35,2 52

43,6 28,8 26,8 56,4 32,4 31,6 54,8 57,2 34,8

27,2 29,2 15,2 77,2 32,4 24,8 39,6 52,8 34,8

102

102 36,8

102

30,4 12,4 102 31,6 31,6 52,4

38

30

19,6 102 29,2 23,6 54,8 34,8 60

26

25,2 102 38,8 78,4 72,8 35,2 30

10 10 10 10 20 20

102

26

25,2 49,6 87,6 34,8

64

34,8

(a)

(b) Figure 7. (a) – (b) Influence of defect dimension on signal amplitude in different depths using Immersion UT method in GFRP plates. Analyzing the following diagram (Figure 8), the UT signal presents a linear behavior decreasing respect to defect depth and highlighting data dispersion due to defect depth. Data analysis shows the better sensitivity of probe 1 MHz in the Contact UT tests for various detected defects in GFRP laminate plates, as in Figure 8. For smaller defects (Figure 8a) with Contact UT technique, the Probe 0,5 also seems unsuitable for all depths. Probes 1 and 1-6 are the highest performing, especially for low depths. The depth influence is negligible on the probe choice for larger defects (Figure 8b) because of the irrelevant signal variability.