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Izod impact strength testFrom Wikipedia, the free encyclopedia

Izod impact strength testing is an ASTM standard method ofdetermining impact strength. A notched sample is generally used todetermine impact strength.

The test is named after the English engineer Edwin Gilbert Izod(1876–1946), who described it in his 1903 address to the BritishAssociation, subsequently published in Engineering.[1]

Impact is a very important phenomenon in governing the life of astructure. For example, in the case of an aircraft, impact can take placeby a bird hitting a plane while it is cruising, or during take off and landing the aircraft may be struck by debrispresent on the runway, and as well as other causes.

An arm held at a specific height (constant potential energy) is released. The arm hits the sample and breaks it.From the energy absorbed by the sample, its impact strength is determined.

The North American standard for Izod Impact testing is ASTM D256. The results are expressed in energy lostper unit of thickness (such as ft-lb/in or J/cm) at the notch. Alternatively, the results may be reported as energylost per unit cross-sectional area at the notch (J/m² or ft-lb/in²). In Europe, ISO 180 methods are used and resultsare based only on the cross-sectional area at the notch (J/m²).

The dimensions of a standard specimen for ASTM D256 are 63.5 x 12.7 x 3.2 mm (2.5" x 0.5" x 1/8"). The mostcommon specimen thickness is 3.2 mm (0.125"), but the width can vary between 3.0 and 12.7 mm (0.118" and0.500").

The Izod impact test differs from the Charpy impact test in that the sample is held in a cantilevered beamconfiguration as opposed to a three-point bending configuration.

This test can also be used to determine the notch sensitivity.

Impact tests are used in studying 'toughness' of material , that is the ability of material to absorb energy duringplastic deformation because of high toughness the material have strength and at the same time large durability .Brittle materials have low toughness means they have low plastic deformation . The impact value of materialused also change. The temperature of the material is directly proportional to impact value and size of specimenis inversely proportional to the impact nature.so at lower temperature durability of the material is decreased .Also with the increase in dimension of specimen .the impact value decreases because the probability of heavyimperfection increases It's value . Standard impact of same material are given below :

Mild steel at 20°C = 60 J1.Ductile iron at 30°C = 50 J2.Wrought iron at 30°C = 50-100 J3.

Contents

1 See also

Izod impact strength test - Wikipedia, the free encyclopedia http://en.wikipedia.org/wiki/Izod_impact_strength_test

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2 References3 External links4 Further reading

See also

Impact forceShock (mechanics)

References^ Izod, Gilbert, 'Testing brittleness of steel', Engineering, 25 September 1903, pp. 431-21.

External links

http://www.matweb.com/reference/izod-impact.asp

Further reading

BS EN ISO 180:2001 - "Plastics. Determination of Izod impact strength"BS EN ISO 13802:2006 - "Plastics. Verification of pendulum impact-testing machines. Charpy, Izodand tensile impact-testing"

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Izod impact strength test - Wikipedia, the free encyclopedia http://en.wikipedia.org/wiki/Izod_impact_strength_test

2 of 2 11/28/2011 2:09 AM