Charpy impact test

Wiktionary

1. n. A test of the impact strength of a material, used to determine its relative ductility or brittleness. The test is executed by swinging a large, heavy hammer on a pendulum from a predetermined height. The hammer fractures the material sample, usually a block of a certain size with a notch cut in it. The height to which the pendulum swings is used to calculate the energy necessary to fracture the sample.