Measurement Of Crack Opening Displacement In Weldments With Particular Reference To Offshore Structures

TWI Industrial Member Report Summary 111/1980

By H G Pisarski and M G Dawes

Background

The ways in which the fracture toughness of weldments is influenced by the preparation of welded test panels are reviewed with particular reference to the fabrication of offshore structures. Attention is drawn to the need to base fracture assessments on data obtained from weldments which are representative of those present in the structure in order to avoid brittle fracture. The methods of measuring COD fracture toughness in the weld metal and heat affected zone (HAZ) are reviewed. In addition the important influences of notch orientation and specimen geometry on the results are discussed. The method of analysing test records together with a summary of the British Standard method of calculating COD is presented. Finally, a review is made of the factors affecting the conservatism in the method of measuring COD and in assessing the fracture resistance of a structure.