TWI, Abington, Cambridge
TWIRolls Royce and Associates, Derby,
Pages: 15 Published: Jan 1998
Existing storage tank fracture prevention design criteria aim at the avoidance of fracture initiation. However, catastrophic failures have shown that the avoidance of crack initiation can never be guaranteed in any absolute sense. Consequently, European specifications increased initiation toughness requirements to reduce further the risk of failure and modified tank design concepts to alleviate the consequences of failure. It could be argued on safety and economic grounds that the use of crack arrest concepts for storage tanks may be the better option. In the present paper, the comparison of a collection of structurally representative large-scale test results with small-scale material characterisation tests shows that there is now a wealth of data available supporting the use of the ‘Pellini’ drop-weight test as a proxy for structural crack arrest behaviour, which is therefore recommended as design criterion for crack arrest during storage tanks fabrication. It is noted that, for a complete structural integrity evaluation of storage tanks, it is necessary to also consider the ductile tearing stability of long arrested cracks.
Storage tanks, crack arrest, design criteria, fracture avoidance, drop-weight test
Paper ID: STP12350S