Fracture mechanics based scaling criteria for miniature and subsize Charpy-V specimens

Besides the normal-size (ISO-V) Charpy specimen (10*10*55 mm exp 3 ), various types of sub-size specimens have been introduced. One standardized sub-size specimen is the so-called KLST specimen, which size is 3*4*27 mm exp 3 and the center notch is 1 mm (DIN 50 115). However, the test data published for the KLST specimen, as well as sub-size specimens in general, is still very limited, though they can provide an overwhelmingly effective use of test material. The results from small specimen testing are typically used to evaluate the fracture behaviour of the ISO-V Charpy specimen. If there are no test results available for the correlation, as there usually is not, a general correlation has to be applied to evaluate the fracture behaviour of the ISO-V specimen. The applicability of a sub-size specimen depends therefore significantly on how reliably this relationship has been established. Here, the Charpy-V test is given a fracture mechanical interpretation and, based on this, new generally applicable scaling criteria are proposed both for miniature as well as sub-size Charpy-V specimens.