Multicrack Localization in Rotors Based on Proper Orthogonal Decomposition Using Fractal Dimension and Gapped Smoothing Method

Table 2

Cases of the rotor with cracks of varying depths at different locations.

Case	Crack 1	Crack 2	Relative phase angle
1	0.1, 200–220 mm (the 11th element)	0.1, 320–340 mm (the 17th element)	0°
2	0.1, 200–220 mm (the 11th element)	0.2, 320–340 mm (the 17th element)	0°
3	0.2, 200–220 mm (the 11th element)	0.2, 320–340 mm (the 17th element)	0°
4	0.3, 200–220 mm (the 11th element)	0.4, 320–340 mm (the 17th element)	0°
5	0.2, 120–140 mm (the 7th element)	0.2, 320–340 mm (the 17th element)	0°
6	0.2, 20–40 mm (the 3rd element)	0.2, 280–300 mm (the 14th element)	0°
7	0.2, 200–220 mm (the 11th element)	0.2, 320–340 mm (the 17th element)	90°
8	0.2, 200–220 mm (the 11th element)	0.2, 320–340 mm (the 17th element)	180°