계장화 샬피 충격시험에 의한 노치형상에 따른 동적파괴인성치의 평가

Dynamic fracture toughness is evaluated in terms of notch shape, notch depth and impact velocity of instrumented Charpy test. Specimen used is SM4SC. The results obtained are as follows: (1) Dynamic calibration of instrumented tup is important in addition to static calibration for the reliance of instrumented Charpy test. (2) Magnitude of inertia force in instrumented Charpy test has no relation with notch shape or notch depth. However, It increases as the impact velocity increases. (3) For the U-notch of notch depth 2mm and 3mm, the fomula obtained by crack initiation load should be used to determine the dynamic fracture toughness. (4) For the V-notch of any notch depth, either the formula obtained by crack initiation load or that by impact energy may be used to determine the dynamic fracture toughness. However, for the notch depth 2mm and 3mm, the formula by crack initiation load should be used.