Introduction

Abstract

Fracture control of structures is the concerted effort by designers, metallurgists, production and maintenance engineers, and inspectors to ensure safe operations without catastrophic fracture failures. Of the various structural failure modes (buckling, fracture, excessive plastic deformation) fracture is only one. Very seldom does a fracture occur due to an unforeseen overload on the undamaged structure. Usually, it is caused by a structural flaw or a crack: due to repeated or sustained “normal” service loads a crack may develop (starting from a flaw or stress concentration) and grow slowly in size, due to the service loading. Cracks and defects impair the strength. Thus, during the continuing development of the crack, the structural strength decreases until it becomes so low that the service loads cannot be carried any more, and fracture ensues. Fracture control is intended to prevent fracture due to defects and cracks at the (maximum) loads experienced during operational service.