ISO 18437-3-2005 Mechanical vibration and shock - Characterization of the dynamic mechanical properties of visco-elastic materials - Part 3 Cantilever shear bea.pdf

1、INTERNATIONAL STANDARD ISO 18437-3 First edition 2005-04-15 Reference number ISO 18437-3:2005(E) ISO 2005 Mechanical vibration and shock Characterization of the dynamic mechanical properties of visco-elastic materials Part 3: Cantilever shear beam method Vibrations et chocs mcaniques Caractrisation

2、des proprits mcaniques dynamiques des matriaux visco-lastiques Partie 3: Mthode du faisceau par cisaillement en encorbellementISO 18437-3:2005(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

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7、 E-mail copyrightiso.org Web www.iso.org Published in SwitzerlandISO 18437-3:2005(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 Force measurement 3 4.3 D

8、isplacement transducer . 4 4.4 Clamping system . 4 4.5 Environmental chamber 5 4.6 Computer . 5 5 Operating procedure . 5 5.1 Sample preparation and mounting 5 5.2 Conditioning 6 5.3 Cantilever shear beam analysis . 7 5.4 Calibration and measurement 8 5.5 Number of test pieces 8 5.6 Temperature cycl

9、e . 8 6 Analysis of results . 9 6.1 Time-temperature superposition . 9 6.2 Data presentation 9 6.3 Test report 10 Annex A (informative) Linearity of resilient materials . 11 Annex B (informative) Time-temperature superposition 12 Bibliography . 14ISO 18437-3:2005(E) iv ISO 2005 All rights reserved F

10、oreword ISO (the International 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 te

11、chnical committee has been 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

12、of electrotechnical standardization. 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

13、 to the member bodies for voting. 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 f

14、or identifying any or all such patent rights. ISO 18437-3 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-el

15、astic materials: Part 2: Resonance method Part 3: Cantilever shear beam method Part 4 (Impedance method) is under preparation.ISO 18437-3:2005(E) ISO 2005 All rights reserved v Introduction Visco-elastic materials are used extensively to reduce vibration magnitudes in structural systems through the

16、dissipation of energy (damping) 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 dissipa

17、tion is due to interactions 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 gi

18、ven application determines the system performance. The goal of this part of ISO 18437 is to provide details on the principle of operation of a cantilever shear beam method that avoids common clamping errors through the use of fixed ends, the measurement equipment, in performing the measurements, and

19、 analysing the resultant data. A further intent is to assist users of this method and to provide uniformity in the use of this method. This part of ISO 18437 applies to the linear behaviour observed at small strain magnitudes.INTERNATIONAL STANDARD ISO 18437-3:2005(E) ISO 2005 All rights reserved 1

20、Mechanical vibration and shock Characterization of the dynamic mechanical properties of visco-elastic materials Part 3: Cantilever shear beam method 1S c o p e This part of ISO 18437 defines a cantilever shear beam method for determining from laboratory measurements the dynamic mechanical properties

21、 of the resilient materials used in vibration isolators. Common errors due to clamping the specimen are avoided by using fixed ends so there is no rotational motion of the beam at its ends. This part of ISO 18437 is applicable to shock and vibration systems operating from a fraction of a hertz to ab

22、out . 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) the transmission of l

23、ow-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 18437-2 are used for the design of efficient vibr

24、ation 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 condition for the valid

25、ity 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 preload. Measurements

26、 using this method are made over two decades in frequency (typically to ) 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 a single re

27、ference temperature) than initially measured at a given temperature. NOTE For the purpose 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 and frequency

28、and, if applicable, a static preload. 20 kHz 0,3 Hz 30 Hz 10 3 Hz 10 9 HzISO 18437-3:2005(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 unda

29、ted 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

30、-1:2001, 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 Par

31、t 1: 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 terms and definitions given in ISO 472, ISO 2041, ISO 4664-1, ISO 6721-1, ISO 10112, ISO 10846-

32、1, ISO 23529 and following terms and definitions 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

33、real part and 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

34、part of the 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, ti

35、me and temperature are equivalent to the extent that data at one temperature are superimposed 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 o

36、ne set of constant- temperature data to superpose upon another set of data E EE ISO 18437-3:2005(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 sp

37、ecific volume 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

38、 factor. That 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 elast

39、ic support, 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 prin

40、ciple of superposition 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

41、 2 In practice, 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

42、 procedure checks for a proportional relationship between the response and the excitation. 4 Test equipment (see Figure 1) 4.1 Electro-dynamic vibration generator The vibration generator induces an oscillating sinusoidal cantilever shear strain into the sample beam at the selected frequency. An elec

43、tro-dynamic vibration generator, with the following specifications, is typical of that required to provide a driving force for the specimen in a typical test: frequency range: to ; force rating: ; amplitude: . 4.2 Force measurement Typically the force is inferred by measuring the magnitude and phase

44、 of the current driving the electro-dynamic vibration generator. The force shall be calibrated using a known mass. The following specifications apply: frequency range: to ; uncertainty: . 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 (t) x 1 (t) x 2 (t) 0,3 Hz 30 Hz 10 N 10

45、0 m 0,3 Hz 30 Hz 0,5 %ISO 18437-3:2005(E) 4 ISO 2005 All rights reserved 4.3 Displacement transducer To eliminate inertial effects, a non-contacting sensor (typically an eddy current type or an optical encoder that is appropriately calibrated) with the following specifications shall be used to measu

46、re the specimen complex displacement, magnitude and phase: frequency range: to ; uncertainty: . 4.4 Clamping system One end of the specimen is clamped rigidly to a frame using the attached end block. (See 5.1.) The driven end block is clamped into a fixture actuated by an electro-dynamic vibration g

47、enerator via a rigid drive shaft. The rigidity of the drive shaft and clamping fixture shall be tens to hundreds times larger that the bending stiffness of the specimen so that all of the measured displacement may be attributed to sample deformation. Key 1 beam specimen 2 specimen end blocks 3 speci

48、men clamps 4 temperature probe 5 environmental chamber 6d r i v e s h a f t 7 electro-dynamic vibration generator 8 force sensor 9 displacement sensor 10 driver input 11 instrument controls for force, displacement and driver units 12 computer 13 temperature probe NOTE The drive shaft is rigidly atta

49、ched to the sample clamp and vibration generator so motion is that of a shear beam. Figure 1 Schematic diagram of test apparatus 0,3 Hz 30 Hz 0,5 %ISO 18437-3:2005(E) ISO 2005 All rights reserved 5 This clamping system assures that the sample motion is confined to a cantilever shear beam mode with fixed- fixed ends. Figure 2 shows the required mode of deformation. While in the past it was common not to use end blocks, their use has been found necessary