Inspections of pressure vessel head penetrations

New brittle fracture model for the European pressure vessel standard

“…The results of the studies in Refs. [15,17] all are consistent with a t 50 value of 15 mm, see Fig. 2.…”

“…Q(t) has a fairly constant value (0.25) for gauges above 45, 35 and 20 mm for t 50 Z15, 10 and 5 mm, respectively. The minimum detectable crack depth was 7.5 [15], 10 [16], and 7 mm [17] in the three studies. Measured as a fraction of the gauge thickness, the minimum detectable crack depth was 50% of 15 mm in Ref.…”

“…However, for gauges below 10 mm, the assumption aZt/4 is questionable. D'Annucci et al [15] studied outer defects on pressure vessel heads with a wall thickness of 15 mm and found that these defects were detectable only if 50% of the wall thickness had been penetrated. They also claim that other authors have found similar results.…”

“…Measured as a fraction of the gauge thickness, the minimum detectable crack depth was 50% of 15 mm in Ref. [15], and 30% of 10-25 mm in Ref. [17].…”