page_title: Izod impact strength test
section_title: Impact energy
hierarchical_section_title: Izod impact strength test / Impact energy
caption_attribution_description: English: This image describes how the Izod test is done.
context_page_description: The Izod impact strength test is an ASTM standard method of determining the impact resistance of materials. A pivoting arm is raised to a specific height and then released. The arm swings down hitting a notched sample, breaking the specimen. The energy absorbed by the sample is calculated from the height the arm swings to after hitting the sample. A notched sample is generally used to determine impact energy and notch sensitivity.
  The test is similar to the Charpy impact test but uses a different arrangement of the specimen under test. The Izod impact test differs from the Charpy impact test in that the sample is held in a cantilevered beam configuration as opposed to a three-point bending configuration.
  The test is named after the English engineer Edwin Gilbert Izod, who described it in his 1903 address to the British Association, subsequently published in Engineering.
context_section_description: Impact is a very important phenomenon in governing the life of a structure. For example, in the case of an aircraft, impact can take place by a bird hitting a plane while it is cruising, or during take off and landing the aircraft may be struck by debris that is present on the runway, and as well as other causes. It must also be calculated for roads if speed breakers are present, in bridge construction where vehicles punch an impact load, etc.
  Impact tests are used in studying the toughness of material. A material's toughness is a factor of its ability to absorb energy during plastic deformation.  Brittle materials have low toughness as a result of the small amount of plastic deformation they can endure. The impact value of a material can also change with temperature. Generally, at lower temperatures, the impact energy of a material is decreased. The size of the specimen may also affect the value of the Izod impact test because it may allow a different number of imperfections in the material, which can act as stress risers and lower the impact energy.
caption: Scheme for the determination of Izod impact strength test results.
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