Impact Strength

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impact strength

[′im‚pakt ‚streŋkth]
Ability of a material to resist shock loading.

Impact Strength


the ability of a material to absorb mechanical energy in the process of deformation and fracture under impact loading. The term “impact strength, ” as well as the term “impact energy, ” is also applied to the amount of energy absorbed before fracture.

To determine impact strength, a bending impact test is commonly used. The specimen in this case has a prismatic bar shape, and a transverse notch is cut in one side of the specimen. The impact strength is regarded as the work required for the fracture of the specimen. In the USSR the work is generally referred to the cross-sectional area of the specimen at the base of the notch and is expressed in joules per square meter, newton-meters per square meter, or kilogram-force-meters per square centimeter.

Impact strength is one of the most important strength characteristics of a metal. When the test temperature is lowered over a series of tests, a sharp drop in impact strength indicates the brittle temperature of the material. Reliable performance of the material is possible only at temperatures above the brittle temperature.

In another type of bending impact test that is sometimes used, a small fatigue crack is produced in advance at the base of the notch; the crack is 1.5 mm in length. In this case a measurement is made of the specific work required for fracture of the specimen. Compared with the impact strength as measured in the first type of test described, the impact strength measured in this way provides a more sensitive characterization of the brittleness of high-strength materials. (See alsoMECHANICAL PROPERTIES OF MATERIALS.)


impact strength, impact energy

The amount of energy required to fracture a material; a measure of the material’s resistance to mechanical shock.
References in periodicals archive ?
Two formulations offer medium and high impact strength for injection molding applications such as those now using ABS.
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The aim of this research is to prepare the composite specimens for conducting the experiment, investigate the impact strength of Bertam leaves fiber reinforced unsaturated polyester, and to optimize the properties of Bertam leaves fiber for use as reinforcement in unsaturated polyester resin by varying fiber sizes.
Aaron Lin, Business development manager at XANTAR LDS at Mitsubishi Engineering-Plastics, said: "This innovative coloured grade has proved a key discriminating factor in the realisation of thin integrated GSM antennas in ultra-thin and light-weight notebooks and tablets, combining excellent impact strength with state-of-the-art flammability and first-rate plating performance.
New alloys, both hypoeutectic and hypereutectic, then were prepared to explore the influence of alloy composition, primarily the aluminum content, on fluidity and impact strength (Table 1).
5 times stronger than the thicker mono LDPE, and impact strength is superior.
Polycarbonate lenses have significant advantages over lenses made of glass or conventional hard resin plastic in terms of thinness, lightness, impact strength and protection from ultra-violet rays.
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The impact strength of PVC/CPE and PVC/ABS hybrids increased with the content of 2-nd phase.
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6] has shown that the incorporation of ABS into PBT leads to blends with very high toughness (notched Izod impact strength about 1000 J/m) and low ductile brittle transition temperatures (DBTT).