ASTM C885-87(R2020) pdf free download

ASTM C885-87(R2020) pdf free download.Standard Test Method for Young’s Modulus of Refractory Shapes by Sonic Resonance
1. Scope
1.1 This test method covers a procedure for measuring the resonance frequency in the flexural (transverse) mode of vibration of rectangular refractory brick or rectangularly shaped monoliths at room temperature. Young’s modulus is calculated from the resonance frequency of the shape, its mass (weight), and dimensions. 1.2 Units—The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.2.1 Although the Hertz (Hz) is an SI unit, it is derived from seconds which is also an inch-pound unit. 1.3 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 appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. 1.4 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
3. Summary of Test Method
3.1 Test specimens are vibrated in flexure over a broad frequency range; mechanical excitation is provided through the use of a vibrating driver that transforms an initial electrical signal into a mechanical vibration. A detector senses the resulting mechanical vibrations ofthe specimen and transforms them into an electrical signal that can be displayed on the screen of an oscilloscope to detect resonance by a Lissajous figure. The calculation ofYoung’s modulus from the resonance frequency measured is simplified by assuming that Poisson’s ratio is 1 ⁄ 6 for all refractory materials.
4. Significance and Use
4.1 Young’s modulus is a fundamental mechanical property of a material. 4.2 This test method is used to determine the dynamic modulus of elasticity of rectangular shapes. Since the test is nondestructive, specimens may be used for other tests as desired. 4.3 This test method is useful for research and development, engineering application and design, manufacturing process control, and for developing purchasing specifications. 4.4 The fundamental assumption inherent in this test method is that a Poisson’s ratio of 1 ⁄ 6 is typical for heteroge- neous refractory materials. The actual Poisson’s ratio may differ.
5. Apparatus
5.1 A block diagram of a suggested test apparatus arrange- ment is shown in Fig. 1. Details of the equipment are as follows:5. Apparatus 5.1 A block diagram of a suggested test apparatus arrange- ment is shown in Fig. 1. Details of the equipment are as follows:5.1.1 Audio Oscillator, having a continuously variable, cali- brated frequency output from about 50 Hz to at least 10 kHz. 5.1.2 Audio Amplifier, having a power output sufficient to ensure that the type of driver used can excite the specimen; the output of the amplifier must be adjustable. 5.1.3 Driver, which may consist of a transducer or a loudspeaker from which the cone has been removed and replaced with a probe (connecting rod) oriented parallel to the direction of the vibration; suitable vibration-isolating mounts. N OTE 1—For small specimens, an air column may preferably be used for “coupling” the loudspeaker to the specimen. 5.1.4 Detector, which may be a transducer or a balance- mounted monaural (crystal or magnetic) phonograph pick-up cartridge of good frequency response; the detector should be movable across the specimen; suitable vibration-isolating mounts. 5.1.5 Pre-Scope Amplifier in the detector circuit, impedance-matched with the detector used; the output must be adjustable. 5.1.6 Indicating Devices, including an oscilloscope, a reso- nance indicator (voltmeter or ammeter), and a frequency indicator, which may be the control dial of the audio-oscillator (accurately readable to 630 Hz or better) or, preferably, a frequency meter, for example, a digital frequency counter. 5.1.7 Specimen Support, consisting of two knife edges (can be steel, rubber-coated steel, or medium-hard rubber) of a length at least equal to the width of the specimens; the distance between the knife edges must be adjustable. N OTE 2—The support for the knife edges may be a foam rubber pad, and should be vibration-isolated from drive and detector supports. N OTE 3—Alternatively, knife edges can be omitted and the specimen may be placed directly on a foam rubber pad if the test material is easily excitable due to its composition and geometry.