< div class=" SectionLevel2" > < p class=" subsec1 cdone2" > < span class=" Head3 cdone" > 1.1< / span> & #x00a0 This test method determines the fatigue behavior of polymer matrix composite materials subjected to tensile cyclic loading. The composite material forms are limited to continuous-fiber or discontinuous-fiber reinforced composites for which the elastic properties are specially orthotropic with respect to the test direction. This test method is limited to unnotched test specimens subjected to constant amplitude uniaxial in-plane loading where the loading is defined in terms of a test control parameter.

< / div> < div class=" SectionLevel2" > < p class=" subsec1 cdone2" > < span class=" Head3 cdone" > 1.2< / span> & #x00a0 This test method presents two procedures where each defines a different test control parameter.

< div class=" SectionLevel3" > < p class=" subsec2 cdone2" > < span class=" Head4 cdone" > 1.2.1< / span> & #x00a0 < span class=" Head4Title cdone" > Procedure A& #x2014 < / span> A system in which the test control parameter is the load (stress) and the machine is controlled so that the test specimen is subjected to repetitive constant amplitude load cycles. In this procedure, the test control parameter may be described using either engineering stress or applied load as a constant amplitude fatigue variable.

< / div> < div class=" SectionLevel3" > < p class=" subsec2 cdone2" > < span class=" Head4 cdone" > 1.2.2< / span> & #x00a0 < span class=" Head4Title cdone" > Procedure B& #x2014 < / span> A system in which the test control parameter is the strain in the loading direction and the machine is controlled so that the test specimen is subjected to repetitive constant amplitude strain cycles. In this procedure, the test control parameter may be described using engineering strain in the loading direction as a constant amplitude fatigue variable.

< / div> < / div> < div class=" SectionLevel2" > < p class=" subsec1 cdone2" > < span class=" Head3 cdone" > 1.3< / span> & #x00a0 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.

< div class=" SectionLevel3" > < p class=" subsec2 cdone2" > < span class=" Head4 cdone" > 1.3.1< / span> & #x00a0 Within the text the inch-pound units are shown in brackets.

< / div> < / div> < div class=" SectionLevel2" > < p class=" caveat cdone2" > < span class=" Head3 cdone" > 1.4< / span> & #x00a0 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

< / div> < div class=" SectionLevel2" > < p class=" WTOcaveat cdone2" > < span class=" Head3 cdone" > 1.5< / span> & #x00a0 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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