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relationship between the signals at 55 mm and at 50 mm, while a little linear relationships describe the coefficient 0.4772 at 50 mm and at 60 mm and 0.1895 at 50 mm
and at 65 mm. And then, the other coefficients fluctuate with the increase of propagation distance. The signals corresponding to the coefficients in Table 6.2 are shown
in Fig. 6.4. The four signal waves have very similar forms at 50, 55, 60 and 65 mm,
while corresponding correlation coefficients have great differences. The signal wave
0
0.05
0.1
0.15
0.2
0.25
-3
-2
-1
0
1
2
3
4
5
Time(ms)
Vertical velocity(m/s)
Figure of the signal of impact data(50mm)
0
0.05
0.1
0.15
0.2
0.25
-3
-2
-1
0
1
2
3
4
Time(ms)
Vertical velocity(m/s)
Figure of the signal of impact data(55mm)
0
0.05
0.1
0.15
0.2
0.25
-3
-2
-1
0
1
2
3
Time(ms)
Vertical velocity(m/s)
Figure of the signal of impact data(60mm)
0
0.05
0.1
0.15
0.2
0.25
-2
-1
0
1
2
3
Time(ms)
Vertical velocity(m/s)
Figure of the signal of impact data(65mm)
0
0.05
0.1
0.15
0.2
0.25
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
Time(ms)
Vertical velocity(m/s)
Figure of the signal of impact data(140mm)
0
0.05
0.1
0.15
0.2
0.25
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
Time(ms)
Vertical velocity(m/s)
Figure of the signal of impact data(150mm)
0
0.05
0.1
0.15
0.2
0.25
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
Time(ms)
Vertical velocity(m/s)
Figure of the signal of impact data(160mm)
0
0.05
0.1
0.15
0.2
0.25
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
Time(ms)
Vertical velocity(m/s)
Figure of the signal of impact data(170mm)
Fig. 6.4 Acoustic emission signals at different gauges from impact point