Dunos Due to the very large number of tests offered, descriptions of those most commonly requested have been gathered into the following groups: By joining you are opting in to receive e-mail. Asgm K R curve may be superimposed on the family of crack driving curves as shown in Fig. A K R curve is a continuous record of toughness development resistance s crack extension in terms of K R plotted against crack extension in the specimen as a crack is driven under an increasing stress intensity factor, K. Historical Version s — view previous versions of standard. Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard.
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More E It provides a record of the toughness development as a crack is driven stably under increasing applied stress intensity factor K.
For a given material, KR curves are dependent upon specimen thickness, temperature, and strain rate. The amount of valid KR data generated in the test depends on the specimen type, size, method of loading, and, to a lesser extent, testing machine characteristics.
In making this estimate, KR curves are regarded as being independent of initial crack size ao and the specimen configuration in which they are developed. The KR curve may be superimposed on the family of crack driving curves as shown in Fig.
The intersection of the crack driving curves with the KR curve shows the expected effective stable crack extension for each loading condition. The crack driving curve that develops tangency with the KR curve defines the critical loading condition that will cause the onset of unstable fracture under the loading conditions used to develop the crack driving curves.
When a specimen with positive K-gradient characteristics see Note 2 is used, the extent of the KR curve which can be developed is terminated when the crack becomes unstable. Scope 1. A KR curve is a continuous record of toughness development resistance to crack extension in terms of KR plotted against crack extension in the specimen as a crack is driven under an increasing stress intensity factor, K.
The values given in parentheses after SI units are provided for information only and are not considered standard. 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.
ASTM E561 – K-R Curve Determination Testing
ASTM E561 - 19