1. Scope
1.1 This test method determines the axial tensile strength and stress-strain response of continuous fiber-reinforced advanced ceramic composite tubes at ambient temperature under monotonic loading. This test method is specific to tube geometries, because fiber architecture and specimen geometry factors are often distinctly different in composite tubes, as compared to flat plates. 1.2 In the test, a composite tube/cylinder with a defined gage section and a known wall thickness is fitted/bonded into a loading fixture. The specimen/fixture assembly is mounted in the testing machine and monotonically loaded in uniaxial tension at ambient temperature while recording the tensile force and the strain in the gage section. The axial tensile strength and the fracture strength are determined from the maximum applied force and the fracture force. The strains, the proportional limit stress, and the tensile modulus of elasticity are determined from the stress-strain data. 1.3 In this test method, test equipment, gripping methods, testing modes, allowable bending stresses, interferences, tubular test specimen geometries, specimen preparation, test procedures, data collection, calculation, reporting requirements, and precision/bias are addressed. 1.4 This test method applies primarily to advanced ceramic matrix composite tubes with continuous fiber reinforcement: unidirectional (1-D, filament wound), bidirectional (2-D, fabric lay-up), and tridirectional (3-D, braid and weave). These types of ceramic matrix composites are composed of a wide range of ceramic fibers (oxide, graphite, carbide, nitride, and other compositions) in a wide range of crystalline and amorphous ceramic matrix compositions (oxide, carbide, nitride, carbon, graphite, and other compositions). 1.5 This test method does not directly address discontinuous fiber-reinforced, whisker-reinforced, or particulate-reinforced ceramics, although the test methods detailed here may be equally applicable to these composites. 1.6 This test method describes a range of test specimen tube geometries based on past tensile testing of ceramic composites tubes. These geometries are applicable to tubes with outer diameters of 10-150 mm and wall thicknesses of 1-25 mm in which the ratio of the outer diameter-to-wall thickness (dO/t) is between 5-30. 1.6.1 This test method is specific to ambient temperature testing. Elevated temperature testing requires temperature-capable grips and loading fixtures and high-temperature furnaces and heating devices with temperature control and measurement systems. 1.7 Units--The values stated in SI units are to be regarded as the standard. 1.8 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 and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Section 8.
A test standard for ceramic composite tubes is needed because flat plate tests are not applicable to tube geometries. This standard will be used by ceramic composites producers, end users, and testing laboratories to develop, qualify, and proof test composite tubes.
Keywords
ceramic matrix composite; continuous ceramic fiber composite;tubes; cylinders; elastic modulus; modulus of toughness; modulus of resilience; Poissons ratio
The title and scope are in draft form and are under development within this ASTM Committee.
Citing ASTM Standards
[Back to Top]
