TWI Industrial Member Report Summary 137/1981
By UK Briefing Group on Dynamic Testing - Commission X - IIW
The Working Group, which has the task of developing a practical technique of dynamic fracture toughness testing suitable for inclusion in British Standards, has previously made some detailed proposals (Christopher and co-workers, 1976). Following this, the Group decided to verify the applicability of the test specifications by carrying out a series of tests on a single steel (BS 11 rail steel).
Eleven laboratories participated and tests were carried out in accordance with the specifications proposed. Initially, tests were carried out at room temperature and three strain rates. Further series of tests were then done at a single strain rate and three temperatures. These conditions were chosen so as to encompass both LEFM and PYFM behaviour.
The results are presented and an acceptable level of reproducibility is found. A statistical study is described, relating the variability to a number of equipment and test characterising parameters. Variation between laboratories is shown to be less than the specimen to specimen scatter. The latter is not correlated with any principal single cause, which is taken to indicate that the test procedure is sound. However, some small changes are proposed in the test specifications.