Structural Health Monitoring Using Smart Sensors - ideals ...

Normalized accumulated stress
measurement 3 measurement 2 measurement 1
1
0.5
0.3
0
1
0.5
0.3
0
1
0.5
0.3
0
11 12 13 14 1516 17 18 19 15 16 17 18 19 20 21 22 23 19 20 21 22 23 24 25 26 27
Element ID
(a)
Normalized accumulated stress
measurement 3 measurement 2 measurement 1
1
0.5
0.3
0
1
0.5
0.3
0
1
0.5
0.3
0
11 12 13 14 15 16 17 18 19 15 16 17 18 19 20 21 22 23 19 20 21 22 23 24 25 26 27
Element ID
(b)
Figure 8.18. Damage detection (damaged element: Element 19): (a) mass perturbation
DLV; and (b) SDLV.
1
1
Normalized accumulated stress
measurement 3 measurement 2 measurement 1
0.5
0.3
0
1
0.5
0.3
0
1
0.5
0.3
Normalized accumulated stress
measurement 3 measurement 2 measurement 1
0.5
0.3
0
1
0.5
0.3
0
1
0.5
0.3
0
11 12 1314 15 16 17 18 19 15 16 17 18 19 20 21 22 23 19 20 21 22 23 24 25 26 27
Element ID
(a)
Figure 8.19. Damage detection (damaged element: Element 20): (a) mass perturbation
DLV; and (b) SDLV.
0
11 12 13 14 151617 1819 15 16 17 18 19 20 21 22 23 19 20 21 22 23 24 25 26 27
Element ID
(b)
are commonly monitored by sensor communities 1 and 2, resulting in two damage
detection cases per measurement. Repeating the measurement process three times results
in six damage detection cases for each of these elements. When no false damage detection
cases are observed out of six, the corresponding cells in these tables appear as “0/6.” The
numerator represents the number of false damage detection cases, while the denominator
represents the total number of damage detection cases. Elements 3, 4, 5, and 6 are
monitored by only one community; thus, the denominator of the corresponding cells is
three instead of six. Element 11 is monitored by three communities, so the denominator is
nine. When element 8 is damaged, for example, the cell corresponding to this element
represents false-negative damage detection while other cells in the same column represent
153