ASTM C623-1992(2005) Standard Test Method for Youngs Modulus Shear Modulus and Poissons Ratio for Glass and Glass-Ceramics by Resonance《用共振现象对玻璃和玻璃陶瓷材料的杨氏模量、剪切模量及泊松比的标准试验方法》.pdf
《ASTM C623-1992(2005) Standard Test Method for Youngs Modulus Shear Modulus and Poissons Ratio for Glass and Glass-Ceramics by Resonance《用共振现象对玻璃和玻璃陶瓷材料的杨氏模量、剪切模量及泊松比的标准试验方法》.pdf》由会员分享,可在线阅读,更多相关《ASTM C623-1992(2005) Standard Test Method for Youngs Modulus Shear Modulus and Poissons Ratio for Glass and Glass-Ceramics by Resonance《用共振现象对玻璃和玻璃陶瓷材料的杨氏模量、剪切模量及泊松比的标准试验方法》.pdf(7页珍藏版)》请在麦多课文档分享上搜索。
1、Designation: C 623 92 (Reapproved 2005)Standard Test Method forYoungs Modulus, Shear Modulus, and Poissons Ratio forGlass and Glass-Ceramics by Resonance1This standard is issued under the fixed designation C 623; the number immediately following the designation indicates the year oforiginal adoption
2、 or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the elasticproperties of glass
3、 and glass-ceramic materials. Specimens ofthese materials possess specific mechanical resonance frequen-cies which are defined by the elastic moduli, density, andgeometry of the test specimen. Therefore the elastic propertiesof a material can be computed if the geometry, density, andmechanical reson
4、ance frequencies of a suitable test specimenof that material can be measured. Youngs modulus is deter-mined using the resonance frequency in the flexural mode ofvibration. The shear modulus, or modulus of rigidity, is foundusing torsional resonance vibrations. Youngs modulus andshear modulus are use
5、d to compute Poissons ratio, the factorof lateral contraction.1.2 All glass and glass-ceramic materials that are elastic,homogeneous, and isotropic may be tested by this test method.2The test method is not satisfactory for specimens that havecracks or voids that represent inhomogeneities in the mate
6、rial;neither is it satisfactory when these materials cannot beprepared in a suitable geometry.NOTE 1Elastic here means that an application of stress within theelastic limit of that material making up the body being stressed will causean instantaneous and uniform deformation, which will cease upon re
7、movalof the stress, with the body returning instantly to its original size and shapewithout an energy loss. Glass and glass-ceramic materials conform to thisdefinition well enough that this test is meaningful.NOTE 2Isotropic means that the elastic properties are the same in alldirections in the mate
8、rial. Glass is isotropic and glass-ceramics are usuallyso on a macroscopic scale, because of random distribution and orientationof crystallites.1.3 A cryogenic cabinet and high-temperature furnace aredescribed for measuring the elastic moduli as a function oftemperature from 195C to 1200C.1.4 Modifi
9、cation of the test for use in quality control ispossible. A range of acceptable resonance frequencies isdetermined for a piece with a particular geometry and density.Any specimen with a frequency response falling outside thisfrequency range is rejected. The actual modulus of each pieceneed not be de
10、termined as long as the limits of the selectedfrequency range are known to include the resonance frequencythat the piece must possess if its geometry and density arewithin specified tolerances.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. I
11、t is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Summary of Test Method2.1 This test method measures the resonance frequencies oftest bars of suitable geometry by excit
12、ing them at continuouslyvariable frequencies. Mechanical excitation of the specimen isprovided through use of a transducer that transforms an initialelectrical signal into a mechanical vibration. Another trans-ducer senses the resulting mechanical vibrations of the speci-men and transforms them into
13、 an electrical signal that can bedisplayed on the screen of an oscilloscope to detect resonance.The reasonance frequencies, the dimensions, and the mass ofthe specimen are used to calculate Youngs modulus and theshear modulus.3. Significance and Use3.1 This test system has advantages in certain resp
14、ects overthe use of static loading systems in the measurement of glassand glass-ceramics:3.1.1 Only minute stresses are applied to the specimen, thusminimizing the possibility of fracture.3.1.2 The period of time during which stress is applied andremoved is of the order of hundreds of microseconds,
15、makingit feasible to perform measurements at temperatures wheredelayed elastic and creep effects proceed on a much-shortenedtime scale, as in the transformation range of glass, for instance.3.2 The test is suitable for detecting whether a materialmeets specifications, if cognizance is given to one i
16、mportantfact: glass and glass-ceramic materials are sensitive to thermal1This test method is under the jurisdiction of ASTM Committee C14 on Glassand Glass Products and is the direct responsibility of Subcommittee C14.04 onPhysical and Mechanical Properties.Current edition approved Sept. 1, 2005. Pu
17、blished October 2005. Originallyapproved in 1969. Last previous edition approved in 2000 as C 623 92 (2000).2Spinner, S., and Tefft, W. E., “A Method for Determining MechanicalResonance Frequencies and for Calculating Elastic Moduli from These Frequen-cies,” Proceedings, ASTM, 1961, pp. 12211238.1Co
18、pyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.history. Therefore the thermal history of a test specimen mustbe known before the moduli can be considered in terms ofspecified values. Material specifications should include aspecific the
19、rmal treatment for all test specimens.4. Apparatus4.1 The test apparatus is shown in Fig. 1. It consists of avariable-frequency audio oscillator, used to generate a sinusoi-dal voltage, and a power amplifier and suitable transducer toconvert the electrical signal to a mechanical driving vibration.A
20、frequency meter monitors the audio oscillator output toprovide an accurate frequency determination. A suitablesuspension-coupling system cradles the test specimen, andanother transducer acts to detect mechanical resonance in thespecimen and to convert it into an electrical signal which ispassed thro
21、ugh an amplifier and displayed on the vertical platesof an oscilloscope. If a Lissajous figure is desired, the output ofthe oscillator is also coupled to the horizontal plates of theoscilloscope. If temperature-dependent data are desired, asuitable furnace or cryogenic chamber is used. Details of th
22、eequipment are as follows:4.2 Audio Oscillator, having a continuously variable fre-quency output from about 100 Hz to at least 20 kHz. Frequencydrift shall not exceed 1 Hz/min for any given setting.4.3 Audio Amplifier, having a power output sufficient toensure that the type of transducer used can ex
23、cite any specimenthe mass of which falls within a specified range.4.4 TransducersTwo are required: one used as a drivermay be a speaker of the tweeter type or a magnetic cutting heador other similar device, depending on the type of couplingchosen for use between the transducer and the specimen. Theo
24、ther transducer, used as a detector, may be a crystal ormagnetic reluctance type of phonograph cartridge.Acapacitivepickup may be used if desired. The frequency response of thetransducer shall be as good as possible with at least a 6.5-kHzbandwidth before 3-dB power loss occurs.4.5 Power Amplifier,
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