1、ANSI S2.22-1998 AMERICAN NATIONAL STANDARD RESONANCE METHOD FOR MEASURING THE DYNAMIC MECHANICAL PROPERTIES OF VISCOELASTIC MATERIALS Accredited Standards Committee S2. Mechanical Vibration and Shock Standards Secretariat Acoustical Society of America 120 Wall Street, 32nd Floor New York, New York 1
2、0005-3993 Copyright Acoustical Society of America Provided by IHS under license with ASANot for ResaleNo reproduction or networking permitted without license from IHS-,-,- STD-ASA S2-22-ENGL 1998 O383440 0003800 473 W The American National Standards Institute, Inc. (ANSI) is the na- tional coordinat
3、or of voluntary standards development and the clear- ing house in the U.S. for information on national and international standards. The Acoustical Society of America (ASA) is an organization of sci- entists and engineers formed in 1929 to increase and diffuse the knowledge of acoustics and to promot
4、e its practical applications. Copyright Acoustical Society of America Provided by IHS under license with ASANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ANSI S2.22-1998 American National Standard Resonance Method for Measuring the Dynamic Mechanical Properties o
5、f Viscoelastic Materials Secretariat Acoustical Society of America Approved 22 June 1998 American National Standards Institute, Inc. Abstract This Standard defines a method for measuring the dynamic mechanical properties of viscoelastic materials using longitudinal resonance in a bar-shaped test sam
6、ple. The dynamic mechanical properties are expressed in terms of the frequency dependence of Youngs modulus and loss factor at a given reference temperature. The Standard provides information for constructing such equipment and analyzing the recuits obtained. Copyright Acoustical Society of America
7、Provided by IHS under license with ASANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-STD-ASA S2.22-ENGL 1998 0383440 0003802 24b AMERICAN NATIONAL STANDARDS ON ACOUSTICS The Acoustical Society of America (ASA) provides the Secretariat for Accredited Standards Comm
8、ittees S1 on Acoustics, S2 on Mechanical Vibration and Shock, S3 on Bioacoustics, and S12 on Noise. These committees have wide represen- tation from the technical community (manufacturers, consumers, and general- interest representatives). The standards are published by the Acoustical Society of Ame
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15、nal Standard may be revised or withdrawn at any time. The procedures of the American National Standards Institute require that action be taken periodically to reaffirm, revise, or withdraw this Standard. Standards Secretariat Acoustical Society of America 120 Wall Street, 32nd Floor New York, New Yo
16、rk 10005-3993 USA Telephone: +1 212 248 0373 Telefax: + 1 21 2 248 O1 46 E-mail: asastdsaip.org Internet: http:/asa.aip.org O 1998 by the Acoustical Society of America. This Standard may not be reproduced in whole or in part in any form for sale, promotion, or any commercial purpose, or any purpose
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18、r ResaleNo reproduction or networking permitted without license from IHS-,-,-Contents Page Foreword ii Introduction 1 O 1 Scope. purpose. and applications . 1 1.1 Scope . 1 1.2 Purpose 1 1.3 Applications 1 2 Informative references . 1 3 Definitions 1 3.2 Loss factor . 1 3.3 Fast Fourier transform 1
19、. . 3.1 Youngs modulus . 1 . 3.4 3.5 3.6 3.7 4 4.1 4.2 4.3 4.4 4.5 Frequency response function . 2 Time-temperature superposition 2 Shift factor . 2 Glass transition temperature . 2 Test equipment . 2 Electromagnetic shaker 2 Accelerometers . 2 Charge amplifiers . 2 Test stand . 2 Environmental cham
20、ber . 2 4.6 Dual channel spectrum analyzer 3 4.7 Computer 3 5 5.1 5.2 5.3 6 6.1 6.2 6.3 Operating procedures . 3 Sample preparation and mounting 3 Data acquisition 3 Temperature cycle 4 Analysis of results 5 Modulus and loss factor . 5 Time-temperature superposition 5 Data presentation . 6 Figures 1
21、 Schematic diagram of resonance apparatus . 2 2 Typical acceleration ratio (solid line) and phase (dashed line) vs.frequency . 4 i Copyright Acoustical Society of America Provided by IHS under license with ASANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Foreword
22、 This Foreword is for information only, and is not a pari of ANSI S2.22-1998 American National Standard Resonance Method for Measuring the Dynamic Mechanical Properfies of viscoelastic Materials . This Standard was developed under the jurisdiction of Accredited Standards Com- mittee 52, Mechanical V
23、ibration and Shock, which has the following scope: Standards, specifications, methods of measurement and test terminology in the fields of mechanical vibration and shock and condition monitoring and diagnos- tics of machines, but excluding those aspects which pertain to biological safey, tolerance,
24、and comfort. At the time this Standard was submitted to Accredited Standards Committee S2, Mechanical Vibration and Shock, for approval, the membership was as follows: D. J. Evans, Chair R. F. Taddeo, Vice Chair A. Brenig, Secretary Acoustical Society of America D. J. Evans R. F. Taddeo (Alt.) Boyce
25、 Engineering International M. P. Boyce C. Meher-Homji (AA.) Bruel Tele- phone: +1 212 248 0373; Fax +1 212 248 0146. iii Copyright Acoustical Society of America Provided by IHS under license with ASANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-AMERICAN NATIONAL
26、STANDARD ANSI S2.22-1998 American National Standard Resonance Method for Measuring the Dynamic Mechanical Properties of Viscoelastic Materials O Introduction Viscoelastic materials are used extensively to re- duce vibration amplitudes in structural systems through dissipation of energy (damping) or
27、isola- tion of components, and in acoustic applications which require a modification of the reflection, transmission, or absorption of energy. Such sys- tems often require specific dynamic mechanical properties in order to function in an optimum man- ner. Energy dissipation is due to interactions on
28、 the molecular scale and can be measured in terms of the lag between stress and strain in the mate- rial. The viscoelastic properties, modulus and loss factor, of most materials depend on frequency, temperature, and strain amplitude. The choice of a specific material for a given application determin
29、es the system performance. This Standard applies to the linear behavior observed at small strain ampli- tudes. 1 Scope, purpose, and applications 1.1 Scope This Standard defines a procedure for measure- ment and analysis of the dynamic properties of viscoelastic materials using a resonance method. T
30、he Standard applies to materials used in sound and vibration damping systems operating at fre- quencies from a fraction of a hertz to about 20 kHz. 1.2 Purpose The purpose of this Standard is to assist users of this method in setting up the measurement equip- ment, performing the measurements, and a
31、nalyz- ing the resultant data. A further purpose is to pro- mote uniformity in the use of this method. 1.3 Applications This Standard applies to the use of the resonance method to evaluate material characteristics for re- search, quality control, and materials selection. 2 Informative references i A
32、STM D 792-91, Standard Test Method for Density and Specific Gravity (Relative Density) of Plastics by Displacement. 2 T. Pritz, ?Transfer Function Method for Investi- gating the Complex Modulus of Acoustic Materials: Rod-like Specimen,? J. Sound and Vibration 81, 3 W. M. Madigosky and G. F. Lee, ?Im
33、proved resonance technique for material characteriza- tion,? J. Acoust. Soc. Am. 73, 1374-1 377 (1 983). 4 J. L. Buchanan, ?Numerical solution for the dy- namic moduli of a viscoelastic bar,? J. Acoust. Soc. Am. 81, 1775-1786 (1987). 5 J. D. Ferry, Viscoelastic Properties of Poly- mers, 3rd ed., Wil
34、ey, New York, 1980, pp 264-320. 359-376 (1 982). 3 Definitions For the purposes of this Standard, the following definitions apply: 3.1 Young?s modulus. Quotient of tensile stress, in pascals, to resulting tensile strain, or fractional change in length. Young?s modulus for viscoelastic materials is a
35、 complex quantity with symbol E *, having a real pari E ? and an imaginary part E I?. Unit, pascal (Pa). NOTE - Physically, the real component of Young?s modulus represents elastic stored mechanical en- ergy. The imaginary component is a measure of mechanical energy loss. See 3.2. 3.2 loss factor. R
36、atio of the imaginary part of the Young?s modulus of a material to the real part of the Young?s modulus (the tangent of the argu- ment of the complex Young?s modulus). NOTE -When there is energy loss in a material, the strain lags the stress by a phase angle, 8 The los5 factor is equal to tan 6. 3.3
37、 fast Fourier transform. An algorithm or cai- culation procedure for obtaining the discrete Fou- rier transform (DFQ with a greatly reduced num- ber of arithmetic operations compared with a direct evaluation. 1 O 1998 Acoustical Society of America Copyright Acoustical Society of America Provided by
38、IHS under license with ASANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ANSI S2.22-1998 3.4 frequency response function. For the pur- poses of this Standard, the quotient of the cross spectrum of the signals produced by accelerom- eters at the output and input of
39、 a sample under test to the autospectrum of the signal produced by an accelerometer at the input to the test sample. NOTE - The frequency response function is some- times known as the transfer function. It is actually a special case of the transfer function. 3.5 time-temperature superposition. Prin-
40、 ciple by which, for viscoelastic materials, time and temperature are equivalent to the extent that data at one temperature can be superimposed upon data taken at different temperature merely by shift- ing the data curves along the frequency axis. 3.6 shift factor. Measure of the amount of shift alo
41、ng the logarithmic axis of frequency for one set of constant temperature data to superimpose upon another set of data. 3.7 glass transition temperature. Tempera- ture at which a viscoelastic material changes state from glassy to rubbery. The glass transition tem- perature is typically determined fro
42、m the inflection point of a specific heat vs. temperature plot and represents an intrinsic material property. Symbol: Tg . Unit, degrees Celsius (“C). NOTE - T, is not the peak in the dynamic mechani- cal loss factor. That peak occurs at a higher tempera- ture than Tg and varies with the measurement
43、 fre- quency, hence is not an intrinsic material property. 4 Test equipment A schematic diagram of the test equipment is shown in figure 1. 4.1 Electromagnetic shaker An electromagnetic shaker, with the following specifications, is required to provide a driving force for the test specimen: (1) frequ
44、ency range: 25 Hz to 18 kHz; (2) force rating: 5 N. 4.2 Accelerometers Piezoelectric accelerometers, with the following specifications, are required to measure the input and output acceleration of the test sample: (1 ) frequency range: 25 Hz to 18 kHz; (2) charge sensitivity: 1 pC/g,; (3) mass: 1 g.
45、 CONTROLLED TEMPERATURE CHAMBER I DUAL CHANNEL SPECTRUM ANALYZER COMPUTER y, TEST/ IM / E N / - ACCELEROMETERS Figure 1 - Schematic diagram of resonance apparatus. NOTE - The accelerometer mass limitation excludes its connecting electric cable. 4.3 Charge amplifiers Charge amplifiers with a sensitiv
46、ity of no less than 1 mV/pC are required to amplify the output signal from the accelerometers. 4.4 Test stand A test stand is required to suspend the shaker and the test sample in a vertical position. 4.5 Environmental chamber An environmental chamber is required to cool the test sample to a tempera
47、ture below room tempera- ture, maintain this temperature until the sample has reached equilibrium, then be capable of in- creasing the temperature of the sample in incre- ments of 5 OC. The chamber shall be capable of operating over the temperature range from -60 OC to 70 “C and be controllable with
48、in 0.5 OC. NOTES 1 The required temperature range is appropriate for a viscoelastic material having a glass transition tem- perature greater than -45 “C. Materials with lower glass transition temperatures will require a lower starting temperature point. 2 Some materials are sensitive to humidity and
49、 it may be desirable to control or at least record the relative hurnidry in the chamber. 2 O 1998 Acouscai Society of America Copyright Acoustical Society of America Provided by IHS under license with ASANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-4.6 Dual-channel spectrum analyzer A dual channel spectrum analyzer, with the follow- ing capabilities, is required to dri
