CMODN 037,000 cyclesVent valveWelded 2:1 end cap (Side A)Lifting lugSpiral seam, 50.8° to axisX70 spool, 30 in OD × 0.441 in wallSteel test chamberGauge cables to DAQTimber cribbingClip gauge over EDM notchWelded end cap (Side B)Monitor: CMOD vs cyclesData acquisition cabinetAccumulatorWater reservoirWater inletHigh-pressure hoseTriplex pumpElectric motorPressure gaugeN1N2N3N4N5N6
The selected clip gauge, its notch and its traceSpool: 30 in OD, 0.441 in wall, X70, spiral seam at 50.8°The full-scale test as a machine. Water from the pump skid cycles the end-capped spool between 206 and 1,482 psi (R = 0.139, hoop stress 72 % of SMYS). Six EDM notches at the toe of the spiral seam each carry a clip gauge; the monitor replays their crack-mouth opening as digitised from the test. Notch 1 broke through at 11,951 cycles, when the records of both deep notches end; the shallow notches showed no measurable opening until about 26,000–29,000 cycles. From this side Notches 3 and 4 are on the far side of the pipe, so only their cables show.