Fracture Toughness Testing
A tremendous amount of progress has been made in fracture toughness testing over the past 15 years since ASTM Committee E24 was established to focus on the development of fracture test standards [1–6]. From the early leadership of J. R. Low, Jr., and the consistent effort of W. F. Brown, Jr., R. H. Heyer, J. E. Srawley, E. T. Wessel, and many other committee members, several fracture test standards now exist and a number of new methods are being explored for possible standardization. It is the purpose of this chapter to review the available documents, calling attention to those areas of continuing refinement, and to look at new developments likely to lead to new test standards some time in the future.
The variety of methods now available and under consideration are summarized in Figure 1. For purposes of this chapter, the breakdown in Figure 2 will be used, first concentrating on methods for the direct measurement of fracture toughness parameters with potential design implications, and following up with those methods aimed primarily at screening or quality control tests for fracture toughness, which may be most useful because of their relatively lower cost and reasonable correlatability with the more direct fracture toughness parameters.
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