Linear Elastic Fracture Toughness (KIc) and Dynamic Tear Transition
Defence Research Establishment Atlantic Dartmouth, Nova Scotia Canada
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The design of a modem warship is a very complex task. Some of the greatest concerns in the design are the selection of proper materials and welding techniques. The aim of the selection is to reach a design, which enables the whole structure to have a ductile behaviour under all operating conditions. This report concentrates on Linear Elastic K type tests at temperatures where the Dynamic Tear energy was less than 133 joules for a 16 mm specimen. 133 joules was selected since it has been suggested that nil ductility occurs at that point for a standard Dynamic Tear Specimen. A background on the subject at hand and a proposed new transition curve interpretation is given. The materials composition and the dynamic tear transition behaviour of three weldments and a Grade A steel chosen for testing are shown. Precracking and fracture toughness procedures are given. The fracture toughness experimental results are shown for all temperatures. A proposed relationship between the shear lip size and the critical plastic zone size is used to determine the validity of the results.
- Marine Engineering