BS ISO 21971:2019 pdf free

BS ISO 21971:2019 pdf free.Fine ceramics (advanced ceramics, advanced technical ceramics)
A prepared tubular test specimen of specified dimensions is inserted into an appropriate test fixture assembly and subjected to monotonic loading via indirect internal pressure up to fracture. Uniform radial pressure is produced using hydraulic oil injection with a piston through an elastomeric bladder located inside the tubular test specimen. The elastomeric bladder mates to the inner diameter of the tubular test specimen, thus causing its expansion under pressure. The test is performed at constant piston displacement or constant strain (or constant loading rate). Both the applied pressure and resulting hoop tensile strain are measured and recorded simultaneously. The hoop tensile strength and corresponding strain are determined from the burst pressure while the various other hoop tensile properties are determined from the stress-strain response data.Generally, the test is carried out under conditions of ambient temperature and environment.
NOTE 1 The resulting force from internal pressure loading is applied in the radial direction. Monotonic refers to a continuous non-stop test rate with no reversals from test initiation to final fracture.
NOTE 2 The method described in this document does not cover the possibility of applying pressurization via a dense rubber material in compressive without fluid.
The gripping device shall be able to maintain the tubular test specimen in position to withstand internal pressure induced by the expansion of the elastomeric bladder while allowing it to move radially. An example of construction detail is shown in Figure 2 for which the tubular test specimen is mounted on a spacer flange. A cover plate is clamped on the flange with two screws to obtain a correct alignment.
The brittle nature of the CMCs requires particular attention to minimize crack initiation and fracture.Therefore, it is recommended that the attachment screws are released and then the adjustment screw adjusted to push the mating flanges back slightly until they come into contact with the tube, but without applying any axial force to it.BS ISO 21971 pdf free download.