7 An Acoustic Emission Source Localization Method Based Ant Colony …
77
Table 7.1 Location results and errors of ACLM and TD (Unit: cm)
The coordinates of AE
source
ACLM
TD
X
Y
X Y
D
X
Y
X Y
D
(27.5, 2.5)
26.5
2.5
−1
0
1.0 27.2
0.0 −0.3 −2.5 2.5
26.5
2.5
−1
0
1.0 27.2
0.0 −0.3 −2.5 2.5
(32.5, 2.5)
32
2.5
−0.5 0
0.5 31.2
4.9 −1.3 2.4
2.7
31.5
2.5
−1
0
1.0 31.1
5.1 −1.4 2.6
3.0
(37.5, 2.5)
37.5
4.5
0
2
2.0 35.1
6.2 −2.4 3.7
4.4
37.5
5.5
0
3
3.0 35.5
6.3 −2.0 3.8
4.3
(42.5, 2.5)
42.5
6
0
3.5
3.5 41.1
4.8 −1.4 2.3
2.7
44.5
3.5
2
1
2.2 41.2
4.6 −1.3 2.1
2.5
(37.5, 7.5)
37.5
7.5
0
0
0.0 37.5
6.3 0.0
−1.2 1.2
37.5
7.5
0
0
0.0 37.5
6.4 0.0
−1.1 1.1
(42.5, 7.5)
42.5
8
0
0.5
0.5 42.4
7.9 −0.1 0.4
0.4
42.5
9
0
1.5
1.5 41.8
8.7 −0.7 1.2
1.4
(47.5, 7.5)
45
9.5
−2.5 2
3.2 45.1 10.6 −2.4 3.1
3.9
45
9.5
−2.5 2
3.2 45.4 10.6 −2.1 3.1
3.7
(42.5, 12.5)
47
12
4.5
−0.5 4.5 48.4 14.0 5.9
1.5
6.1
43
12.5 0.5
0
0.5 44.5 12.7 2.0
0.2
2.0
(47.5, 12.5)
47.5
14
0
1.5
1.5 48.8 15.0 1.3
2.5
2.8
45.5
12.5 −2
0
2.0 45.3 14.2 −2.2 1.7
2.8
(47.5, 17.5)
47.5
20
0
2.5
2.5 50.0 19.5 2.5
2.0
3.2
47.5
20
0
2.5
2.5 50.0 19.5 2.5
2.0
3.2
(47.5, 22.5)
47.5
25
0
2.5
2.5 50.0 23.9 2.5
1.4
2.9
47.5
25
0
2.5
2.5 50.0 24.0 2.5
1.5
2.9
Average error
−0.2 1.2
1.9
0.1
1.4
2.8
7.4 Conclusions
In this paper, an ant colony Localization Method (ACLM) without premeasured
velocity was proposed. It can bypass the empty area and also does not need to
premeasure the velocity of the structure. Therefore, this method can be applied to the
structure with complex geometry during the monitoring process, which can reduce
the location error caused by the changing wave velocity.
To evaluate the effectiveness of the ACLM, the lead-breaking test was carried
out on the square flagstone with cavity. The location results show that the average
location error obtained by the ACLM is 1.9 cm, and its average location accuracy is
32% higher than the TD. It can be concluded that the ACLM can effectively adapt
to complex structures. This method is also applicable to three-dimension complex
structures for source location.
77
Table 7.1 Location results and errors of ACLM and TD (Unit: cm)
The coordinates of AE
source
ACLM
TD
X
Y
X Y
D
X
Y
X Y
D
(27.5, 2.5)
26.5
2.5
−1
0
1.0 27.2
0.0 −0.3 −2.5 2.5
26.5
2.5
−1
0
1.0 27.2
0.0 −0.3 −2.5 2.5
(32.5, 2.5)
32
2.5
−0.5 0
0.5 31.2
4.9 −1.3 2.4
2.7
31.5
2.5
−1
0
1.0 31.1
5.1 −1.4 2.6
3.0
(37.5, 2.5)
37.5
4.5
0
2
2.0 35.1
6.2 −2.4 3.7
4.4
37.5
5.5
0
3
3.0 35.5
6.3 −2.0 3.8
4.3
(42.5, 2.5)
42.5
6
0
3.5
3.5 41.1
4.8 −1.4 2.3
2.7
44.5
3.5
2
1
2.2 41.2
4.6 −1.3 2.1
2.5
(37.5, 7.5)
37.5
7.5
0
0
0.0 37.5
6.3 0.0
−1.2 1.2
37.5
7.5
0
0
0.0 37.5
6.4 0.0
−1.1 1.1
(42.5, 7.5)
42.5
8
0
0.5
0.5 42.4
7.9 −0.1 0.4
0.4
42.5
9
0
1.5
1.5 41.8
8.7 −0.7 1.2
1.4
(47.5, 7.5)
45
9.5
−2.5 2
3.2 45.1 10.6 −2.4 3.1
3.9
45
9.5
−2.5 2
3.2 45.4 10.6 −2.1 3.1
3.7
(42.5, 12.5)
47
12
4.5
−0.5 4.5 48.4 14.0 5.9
1.5
6.1
43
12.5 0.5
0
0.5 44.5 12.7 2.0
0.2
2.0
(47.5, 12.5)
47.5
14
0
1.5
1.5 48.8 15.0 1.3
2.5
2.8
45.5
12.5 −2
0
2.0 45.3 14.2 −2.2 1.7
2.8
(47.5, 17.5)
47.5
20
0
2.5
2.5 50.0 19.5 2.5
2.0
3.2
47.5
20
0
2.5
2.5 50.0 19.5 2.5
2.0
3.2
(47.5, 22.5)
47.5
25
0
2.5
2.5 50.0 23.9 2.5
1.4
2.9
47.5
25
0
2.5
2.5 50.0 24.0 2.5
1.5
2.9
Average error
−0.2 1.2
1.9
0.1
1.4
2.8
7.4 Conclusions
In this paper, an ant colony Localization Method (ACLM) without premeasured
velocity was proposed. It can bypass the empty area and also does not need to
premeasure the velocity of the structure. Therefore, this method can be applied to the
structure with complex geometry during the monitoring process, which can reduce
the location error caused by the changing wave velocity.
To evaluate the effectiveness of the ACLM, the lead-breaking test was carried
out on the square flagstone with cavity. The location results show that the average
location error obtained by the ACLM is 1.9 cm, and its average location accuracy is
32% higher than the TD. It can be concluded that the ACLM can effectively adapt
to complex structures. This method is also applicable to three-dimension complex
structures for source location.