ISO 19587:2021 pdf download.Fine ceramics (advanced ceramics,advanced technical ceramics)
1 Scope
This document specifies a method for the determination of in-plane shear strength of continuous fibre-reinforced ceramic composites at elevated temperature in air or inert atmosphere by the asymmetric four-point bending test on double-edge notched specimens. The shear strength in plane (1,2) can be evaluated, where direction 1 is that of the greater fraction of reinforcement and direction 2 is perpendicular to direction 1. Methods for test piece fabrication, testing modes and rates (load or displacement rate), data collection and reporting procedures are addressed.
This document applies to all ceramic matrix composites with continuous fibre-reinforcement:unidirectional (1D], bidirectional (2D] and tridirectional (xD, with2
ISO 20507, Fine ceramics (advanced ceramics, advanced technical ceramics)一Vocabulary
IEC 60584-1, Thermocouples一Part 1: Reference tables
IEC 60584-2, Thermocouples一Part 2: Tolerances
4 Principle
The in-plane shear strength of continuous fibre-reinforced ceramic composites, as determined by this document, is measured by the asymmetric four-point bending test at elevated temperature in air or inert atmosphere. According to this test, the shear strength is determined by loading a test coupon in the form of a rectangular flat strip with symmetric, centrally located V-notches using a mechanical testing machine and an asymmetric four-point bending fixture. Failure of the test piece occurs by shear force between the V-notches. Schematics of the test set-up and the test piece are shown in Figures 1 and 2, respectively. The free body, bending moment and shear force diagrams by the asymmetric four-point bending flexure are illustrated in Figure 3.
5.1 Test environment
The test environment can have an influence on the measured shear strength. In particular, the behaviour of materials susceptible to slow-crack-growth fracture will be strongly influenced by the test environment and testing rate. Testing to evaluate the maximum strength potential of a material shall be conducted in inert environments, at sufficiently rapid testing rates or both, so as to minimize slow-crack-growth effects. Conversely, testing can be conducted in environments and testing modes and rates representative of service conditions to evaluate material performance under those conditions.When testing is conducted in uncontrolled ambient air with the objective of evaluating maximum strength potential, water partial pressure and temperature shall be monitored and reported, if the tested materials are sensitive to these parameters.ISO 19587 pdf download.