Characteristic experimental data for evaluating the fracture toughness of impact loaded medium-scale-specimens

It is the aim of the reported instrumented tensile impact tests to receive dynamic material (toughness) properties when center cracked panels (CCP) are loaded with a velocity like in the Charpy-V-Notch-test. In the force-time history so-called crack-initiation and -propagation areas are separated by maximum load or when load becomes instabile from an engineering point of view. So, with instrumented CCP-specimen (original-wall-thickness) impact loaded tests can be performed and evaluated successfully. For dynamic fracture the new transition temperature can be measured and characterized by mechanical data and can be correlated to the fracture appearance (brittle or ductile). The load-time-history of impact loaded CCP-specimen with original wall-thickness can describe the stable crack initiation and propagation close to reality. The new test procedure can be a help in material-development or-evaluation. So, materials for impact loaded constructions can be chosen which have a maximum toughness. A rather more important advantage of the medium scale specimen is the possibility to test also welded plates. Recent evaluations show that also the time can be used to characterize the material toughness for impact loading. This correlates with proposals from an ASTM working group. Examples for the time-characterization versus temperature are given. This is also shown for the specific energy W (energy per volume). (orig./HP)