Izod Impact Tester

The Izod impact tester measures a material's toughness by clamping a notched specimen vertically as a cantilever and striking it with a swinging pendulum just above the notch, recording the energy the specimen absorbed from the height the pendulum reaches after breaking it. The English engineer Edwin Gilbert Izod introduced the test in 1903, presenting it as an alternative to the horizontally supported Charpy configuration developed at nearly the same time, with the vertical cantilever clamping method that still bears his name. The Izod test became especially widely used for testing plastics and other polymer materials, where it remains a standard specification test for impact resistance alongside the Charpy method more commonly used for metals.