A Study on Depth Sizing for Surface Cracks in KTX Brake Disc Using Rayleigh Wave

Table 1

Specification of cracks in the brake disc specimen (mm).

No.	Type	Crack gap	Length	Depth
1	Standard	—	7.0	0.5
				1.0
				2.0
				3.0
				4.0
2	H-double	1.0	7.0	2.0
		2.0
		3.0
		4.0
3	V-double	1.0
		2.0
		3.0
4	Triple	1.0
		2.0
		3.0
5	Standard	—	10.0	0.5
				1.0
				2.0
				3.0
				4.0
6	H-double	1.0	10.0	4.0
		2.0
		3.0
		4.0
7	V-double	1.0
		2.0
		3.0
8	Triple	1.0
		2.0
		3.0