Table 1.

Damage cases (experimental operating conditions).

Operating Condition	OC1	OC2	OC3	OC4	OC5	OC6
The depth of the first crack	1.5 mm	3.0 mm	4.5 mm	6.0 mm	7.5 mm	9.0 mm
Operating Condition	OC7	OC8	OC9	OC10	OC11	OC12
The depth of the second crack	1.5 mm	3.0 mm	4.5 mm	6.0 mm	7.5 mm	9.0 mm
Operating Condition	OC13	OC14	OC15	OC16	OC17	OC18
The depth of the third crack	1.5 mm	3.0 mm	4.5 mm	6.0 mm	7.5 mm	9.0 mm
Operating Condition	OC19	OC20	OC21	OC22	OC23	OC24
The depth of the fourth crack	1.5 mm	3.0 mm	4.5 mm	6.0 mm	7.5 mm	9.0 mm

Note: the state of healthy pipeline has no crack, this condition is denoted by 0.