Cost-effective precracking of CHARPY V-NOTCH specimens for fracture toughness testing using a piezo-electric actuator

The evolution in the ASTM standard to more stringent precracking requirements and the large amount of fracture toughness tests annually performed at SCK-CEN, was the motivation to search for novel techniques to gain more control over the precracking process and to reduce the precracking cost. A feasibility study identified the piezo-electric actuator as an excellent candidate for this purpose. A dedicated precracking machine for Charpy V-notch specimens based on a piezo-electric actuator was developed. The high degree of automation allows full control over the precracking process in agreement with current or future standards. The low power consumption, high precracking frequency, low yield loss, low maintenance and minimum operator intervention significantly reduced the precracking cost. A second piezo-precracking was installed in a hotcell and is already providing a reliable service for several years.