Abstract
It is vitally important to measure the brittle crack arrest properties of shipbuilding steels to ensure that accidental damage will not result in total structural failure. Wide-plate test methods allow for direct measurement of the crack arrest toughness but this kind of testing is incredibly expensive. Therefore, there is a need for cheaper and simpler test methods which are able to measure a material’s brittle crack arrest toughness. In this work, Compact Crack Arrest (CCA) testing, which is standardised in ASTM E1221, has been successfully used to measure the crack arrest toughness of thick sections of EH47 shipbuilding steel. The results from this study have been compared to small-scale test methods. It was found that instrumented Charpy testing gives an overprediction of the CCA results, and nil-ductility transition temperature (NDTT) from Pellini tests gives a conservative estimate. The results presented in this study are discussed in terms of the effectiveness of the CCA test method for measurement of brittle crack arrest toughness and integrity assessment of large-scale structures.
Highlights
The issues associated with brittle fracture of shipbuilding steels were first brought to light by the premature failure of some of the Liberty ships during WWII[1]
According to the experimental approach detailed in the ASTM E1221 standard, side-grooved Crack Arrest (CCA) specimens are slowly cyclically loaded under crack-line wedge loading to incrementally increasing peak loads, in order to achieve a rapid run-arrest of a crack with a nearly straight crack front
The present study has proved the possibility of achieving valid re sults from CCA testing on relatively thick (i.e. 80 mm) steel plates
Summary
The issues associated with brittle fracture of shipbuilding steels were first brought to light by the premature failure of some of the Liberty ships during WWII[1]. The most common method to measure brittle crack arrest tough ness is using wide-plate testing [7,8,9,10,11,12,13,14,15,16,17] such as ESSO tests or doubletension tests which have been incorporated into International Stan dard ISO 20064:2019[18]. The obtained results have been compared to predictions of the crack arrest toughness from small-scale testing which are reported in previous research conducted by the authors [26] These predictions rely on determination of reference temperatures and are based on the master curve approach. The specimen preparation, test procedure, experi mental challenges, and the analysis of the test data have been compre hensively explained and are discussed
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