BS ISO 22459:2020 pdf free

BS ISO 22459:2020 pdf free.Fine ceramics – Reinforcement of ceramic composites
The evaluation method is based on an analysis of the nonlinear domain of the force- displacement curve, which is caused by progressive filament failure during the test. The size of this domain is promoted by higher stiffness of the loading and gripping system. When the force-displacement curve does not show this nonlinear domain, the evaluation method of this document cannot be applied.
The distribution of filament rupture strains does not depend on the initial number of filaments for those tows that contain a large number of filaments; hence, it is not affected by the number of filaments which are broken before the test, provided this number remains limited. The determination of the filament strength distribution requires knowledge of the initial cross-sectional area of the tow. The variation in filament diameters, which affects the strength values, is not accounted for.
The Weibull parameters determined by this test method and extrapolated to the respective gauge length cannot be compared directly with those obtained from tensile tests on monofilaments according to ISO 19630 because of variability in test conditions[1].
A strain rate around 10-4s-1 shall be used for all the tests. The corresponding crosshead displacement rate shall be determined from a test on a specimen with the largest gauge length of 300 mm performed according to 9.5. The force-displacement curve obtained from this test shall have the appearance shown in Figure 7. In particular, the curve shall have a linear followed by a nonlinear rising part, as well as a  nonlinear decreasing part. It shall furthermore meet the validity requirements of 9.7. When the force-displacement curve does not meet these criteria, tests at lower crosshead displacement rates shall be performed until this is the case. Calculate the strain rate from the displacement rate and check whether it falls in the required range. If not, decrease the crosshead displacement rate until this is the case. Use this crosshead rate in all subsequent tests, irrespective of the gauge length of the specimen.BS ISO 22459 pdf download.