1、INTERNATIONAL STANDARD ISO 18437-2 First edition 2005-04-15 Reference number ISO 18437-2:2005(E) ISO 2005 Mechanical vibration and shock Characterization of the dynamic mechanical properties of visco-elastic materials Part 2: Resonance method Vibrations et chocs mcaniques Caractrisation des proprits
2、 mcaniques dynamiques des matriaux visco-lastiques Partie 2: Mthode de rsonanceISO 18437-2:2005(E) ii ISO 2005 All rights reserved PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unles
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7、hed in SwitzerlandISO 18437-2:2005(E) ISO 2005 All rights reserved iii Contents Page 1 Scope 1 2 Normative references 2 3 Terms and definitions 2 4 Test equipment (see Figure 1) 3 4.1 Electro-dynamic vibration generator . 3 4.2 Accelerometers 3 4.3 Charge amplifiers 4 4.4 Test stand . 4 4.5 Environm
8、ental chamber 5 4.6 Dual-channel spectrum analyser . 5 4.7 Computer . 5 5 Operating procedures . 5 5.1 Sample preparation and mounting 5 5.2 Conditioning 6 5.3 Number of test pieces . 7 5.4 Data acquisition . 7 5.5 Temperature cycle . 8 6 Analysis of results . 8 6.1 Modulus and loss factor . 8 6.2 T
9、ime-temperature superposition . 10 6.3 Data presentation 10 6.4 Test report 11 Annex A (informative) Linearity of vibration resilient materials 12 Annex B (informative) Time-temperature superposition 13 Bibliography . 15ISO 18437-2:2005(E) iv ISO 2005 All rights reserved Foreword ISO (the Internatio
10、nal Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been
11、established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standar
12、dization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for v
13、oting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all s
14、uch patent rights. ISO 18437-2 was prepared by Technical Committee ISO/TC 108, Mechanical vibration and shock. ISO18437 consists of the following parts, under the general title Mechanical vibration and shock Characterization of the dynamic mechanical properties of visco-elastic materials: Part 2: Re
15、sonance method Part 3: Cantilever shear beam method Part 4 (Impedance method) is under preparation.ISO 18437-2:2005(E) ISO 2005 All rights reserved v Introduction Visco-elastic materials are used extensively to reduce vibration magnitudes in structural systems through the dissipation of energy (damp
16、ing) or isolation of components, and in acoustical applications that require a modification of the reflection, transmission or absorption of energy. Such systems often require specific dynamic mechanical properties in order to function in an optimum manner. Energy dissipation is due to interactions
17、on the molecular scale and is measured in terms of the lag between stress and strain in the material. The visco- elastic properties (modulus and loss factor) of most materials depend on frequency, temperature, and strain magnitude. The choice of a specific material for a given application determines
18、 the system performance. The goal of this part of ISO 18437 is to provide details in constructing the resonance apparatus, in setting up the measurement equipment, in performing the measurements and analysing the resultant data. A further intent is to assist users of this method and to provide unifo
19、rmity in the use of this method. This part of ISO 18437 applies to the linear behaviour observed at small strain magnitudes.INTERNATIONAL STANDARD ISO 18437-2:2005(E) ISO 2005 All rights reserved 1 Mechanical vibration and shock Characterization of the dynamic mechanical properties of visco-elastic
20、materials Part 2: Resonance method 1S c o p e This part of ISO 18437 defines a resonance method for determining from laboratory measurements the dynamic mechanical properties of the resilient materials used in vibration isolators. It is applicable to shock and vibration systems operating from a frac
21、tion of a hertz to about . This part of ISO 18437 is applicable to resilient materials that are used in vibration isolators in order to reduce a) transmissions of unwanted vibrations from machines, structures or vehicles that radiate sound (fluid-borne, airborne, structure-borne, or others), and b)
22、the transmission of low-frequency vibrations that act upon humans or cause damage to structures or sensitive equipment when the vibration is too severe. The data obtained with the measurement methods that are outlined in this part of ISO 18437 and further detailed in ISO 18437-3 are used for the des
23、ign of efficient vibration isolators, the selection of an optimum material for a given design, the theoretical computation of the transfer of vibrations through isolators, information during product development, product information provided by manufacturers and suppliers, and quality control. The co
24、ndition for the validity of the measurement method is linearity of the vibrational behaviour of the isolator. This includes elastic elements with nonlinear static load deflection characteristics, provided that the elements show approximate linearity in their vibrational behaviour for a given static
25、preload. Measurements using this method are made over one or two decades in frequency at a number of temperatures. By applying the time-temperature superposition principle, the measured data are shifted to generate dynamic mechanical properties over a much wider range of frequencies (typically to at
26、 a single reference temperature) than initially measured at a given temperature. NOTE For the purposes of this part of ISO 18437, the term “dynamic mechanical properties” refers to the determination of the fundamental elastic properties, e.g. the complex Youngs modulus as a function of temperature a
27、nd frequency and, if applicable, a static preload. 20 kHz 10 3 10 9 HzISO 18437-2:2005(E) 2 ISO 2005 All rights reserved 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated
28、 references, the latest edition of the referenced document (including any amendments) applies. ISO 472:1999, Plastics Vocabulary ISO 2041:1990, Vibration and shock Vocabulary ISO 4664-1:2005, Rubber, vulcanized or thermoplastic Determination of dynamic properties Part 1: General guidance ISO 6721-1:
29、2001, Plastics Determination of dynamic mechanical properties Part 1: General principles ISO 10112:1991, Damping materials Graphical presentation of the complex modulus ISO 10846-1:1997, Acoustics and vibration Laboratory measurement of vibro-acoustic transfer properties of resilient elements Part 1
30、: Principles and guidelines ISO 23529:2004, Rubber General procedures for preparing and conditioning test pieces for physical test methods 3 Terms and definitions For the purposes of this document, the following terms and definitions given in ISO 472, ISO 2041, ISO 4664-1, ISO 6721-1, ISO 10112, ISO
31、 10846-1, ISO 23259 and the following apply. 3.1 Youngs modulus quotient of normal stress (tensile or compressive) to resulting normal strain, or fractional change in length NOTE 1 Unit is the pascal (Pa). NOTE 2 Y oungs modulus for visco-elastic materials is a complex quantity, having a real part a
32、nd an imaginary part . NOTE 3 Physically, the real component of Youngs modulus represents elastic-stored mechanical energy. The imaginary component is a measure of mechanical energy loss. See 3.2. 3.2 loss factor ratio of the imaginary part of the Youngs modulus of a material to the real part of the
33、 Youngs modulus (the tangent of the argument of the complex Youngs modulus) NOTE When there is energy loss in a material, the strain lags the stress by a phase angle, . The loss factor is equal to tan . 3.3 time-temperature superposition principle by which, for visco-elastic materials, time and temp
34、erature are equivalent to the extent that data at one temperature are superposed upon data taken at a different temperature merely by shifting the data curves along the frequency axis 3.4 shift factor measure of the amount of shift along the logarithmic (base 10) axis of frequency for one set of con
35、stant- temperature data to superimpose upon another set of data E EE ISO 18437-2:2005(E) ISO 2005 All rights reserved 3 3.5 glass transition temperature temperature at which a visco-elastic material changes state from glassy to rubbery, and corresponds to a change in slope in a plot of specific volu
36、me against temperature NOTE 1 Unit is degrees Celsius (C). NOTE 2 The glass transition temperature is typically determined from the inflection point of a specific heat vs. temperature plot and represents an intrinsic material property. NOTE 3 is not the peak in the dynamic mechanical loss factor. Th
37、at peak occurs at a higher temperature than and varies with the measurement frequency; hence is not an intrinsic material property. 3.6 resilient material visco-elastic material intended to reduce the transmission of vibration, shock or noise NOTE 1 It is sometimes referred to as an elastic support,
38、 vibration isolator, shock mounting, absorber or decoupler. NOTE 2 The reduction may be accomplished by the material working in tension, compression, torsion, shear, or a combination of these. 3.7 linearity property of the dynamic behaviour of a resilient material if it satisfies the principle of su
39、perposition NOTE 1 The principle of superposition is stated as follows: if an input produces an output and in a separate test an input produces an output , superposition holds if the input produces the output . This holds for all values of , and , , where and are arbitrary constants. NOTE 2 In pract
40、ice, the above test for linearity is impractical. Measuring the dynamic modulus for a range of input levels can provide a limited check of linearity. For a specific preload, if the dynamic transfer modulus is nominally invariant, the system measurement is considered linear. In effect this procedure
41、checks for a proportional relationship between the response and the excitation. 4 Test equipment (see Figure 1) 4.1 Electro-dynamic vibration generator An electro-dynamic vibration generator is required to provide a driving force for the test specimen, producing an oscillating displacement in the ve
42、rtical direction. The dynamic strain level shall be adjusted to assure linear behaviour (see Annex A). The following specifications are typical: frequency range: to ; force rating: ; peak displacement: . 4.2 Accelerometers A matched pair of accelerometers is required, or a relative calibration corre
43、ction shall be applied. Piezoelectric accelerometers, with the following specifications, are typical of those required to measure the input and output acceleration of the test sample: frequency range: to ; charge sensitivity: . T g T g T g x 1 (t) y 1 (t) x 2 (t) y 2 (t) x 1 (t)+x 2 (t) y 1 (t)+y 2
44、(t) x 1 (t) x 2 (t) 25 Hz 10 kHz 5N1 pC/gISO 18437-2:2005(E) 4 ISO 2005 All rights reserved The mass of the accelerometer plus the lower mounting block should be as small as possible (see 5.1). NOTE It is possible to use other types of sensors, but they need to be functionally equivalent. 4.3 Charge
45、 amplifiers Charge amplifiers with a sensitivity of not less than are required to amplify the output signal from the accelerometers. Alternatively, piezoelectric accelerometers with built-in amplifiers may be used. 4.4 Test stand A test stand is needed to suspend the vibration generator and the test
46、 sample in a vertical position, as shown in Figure 1. The sample and vibration generator shall be positioned so as to eliminate or minimize any horizontal motion. NOTE The presence of horizontal motion will appear as spurious peaks in the spectra. Key 1 electro-dynamic vibration generator 2 mounting
47、 blocks 3 accelerometers 4 test specimen 5 test stand 6 environmental chamber 7 dual-spectrum analyser 8 computer 9 charge amplifiers 10 noise source Figure 1 Schematic diagram of the resonance apparatus 1 mV/pCISO 18437-2:2005(E) ISO 2005 All rights reserved 5 4.5 Environmental chamber An environme
48、ntal chamber is required to cool the test sample to a temperature below room temperature. This temperature shall be maintained until the sample has reached equilibrium, then the temperature of the sample shall be increased in increments of . The chamber should be capable of operating over the temper
49、ature range from to and should be controllable to within . The temperature sensor shall be appropriately calibrated. NOTE 1 The required temperature range is appropriate for a visco-elastic material having a glass transition temperature greater than . Materials with lower glass transition temperatures will require a lower starting temperature point. NOTE 2 Some materials are sensitive to humidity and it may be desirable to control or at least record the re
