BS ISO 18437-1-2012 Mechanical vibration and shock Characterization of the dynamic mechanical properties of visco-elastic materials Principles and guidelines《机械振动和冲击 粘弹性材料动态机械性能特征 .pdf

1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 18437-1:2012Mechanical vibration and shock Characterization of thedynamic mechanical propertiesof visco-elastic materialsPart 1: Principles and guidelinesBS ISO 18437-1:20

2、12 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 18437-1:2012.The UK participation in its preparation was entrusted to TechnicalCommittee GME/21, Mechanical vibration, shock and conditionmonitoring.A list of organizations represented on this committee can beo

3、btained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2012. Published by BSI StandardsLimited 2012ISBN 978 0 580 73613 1ICS 17.160Compliance with

4、a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 31 August 2012.Amendments issued since publicationDate Text affectedBS ISO 18437-1:2012 ISO 2012Mechanical vibration and shock Char

5、acterization of the dynamic mechanical properties of visco-elastic materials Part 1: Principles and guidelinesVibrations et chocs mcaniques Caractrisation des proprits mcaniques dynamiques des matriaux visco-lastiques Partie 1: Principes et lignes directricesINTERNATIONAL STANDARDISO18437-1First edi

6、tion2012-08-15Reference numberISO 18437-1:2012(E)BS ISO 18437-1:2012ISO 18437-1:2012(E)ii ISO 2012 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2012All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electroni

7、c or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www

8、.iso.orgPublished in SwitzerlandBS ISO 18437-1:2012ISO 18437-1:2012(E) ISO 2012 All rights reserved iiiContents PageForeword ivIntroduction v1 Scope 12 Normative references . 13 Terms and definitions . 24 Measurement principles 24.1 General . 24.2 Resonance method . 34.3 Cantilever shear beam method

9、 44.4 Dynamic stiffness method 54.5 Estimation of the Poisson ratio . 75 Time temperature superposition . 96 Specimen conditioning 97 Selection of appropriate method . 9Annex A (informative) Linearity of resilient materials 11Annex B (informative) Analysis of other ISO documents on dynamic testing .

10、12Bibliography .16BS ISO 18437-1:2012ISO 18437-1:2012(E)ForewordISO (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.

11、 Each member body interested in a subject for which a technical 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 Interna

12、tional Electrotechnical Commission (IEC) on all matters 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 Standa

13、rds adopted by the technical committees are circulated 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

14、of patent rights. ISO shall not be held responsible for identifying any or all such patent rights.ISO 18437-1 was prepared by Technical Committee ISO/TC 108, Mechanical vibration, shock and condition monitoring.ISO 18437 consists of the following parts, under the general title Mechanical vibration a

15、nd shock Characterization of the dynamic mechanical properties of visco-elastic materials: Part 1: Principles and guidelines Part 2: Resonance method Part 3: Cantilever shear beam method Part 4: Dynamic stiffness method Part 5: Poisson ratio based on comparison between measurements and finite elemen

16、t analysisiv ISO 2012 All rights reservedBS ISO 18437-1:2012ISO 18437-1:2012(E)IntroductionVisco-elastic materials are used extensively to reduce vibration amplitudes in structural systems through dissipation of energy (damping) or isolation of components, and in acoustical applications that require

17、 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 on the molecular scale and can be measured in terms of the lag between stres

18、s and strain in the material. The visco-elastic properties, modulus, and loss factor of most materials depend on frequency, temperature, strain amplitude, and pre-strain. In addition to modulus and loss factor, sometimes Poisson ratio is an important property required for predictions. The choice of

19、a specific material for a given application determines the system performance. The goal of this International Standard is to provide brief descriptions of the three methods for elastic modulus and loss factor and two methods for Poisson ratio, the details of construction of each apparatus, measureme

20、nt range, and the limitations of each apparatus. This International Standard applies to the linear behaviour observed at small strain amplitudes. ISO 2012 All rights reserved vBS ISO 18437-1:2012BS ISO 18437-1:2012Mechanical vibration and shock Characterization of the dynamic mechanical properties o

21、f visco-elastic materials Part 1: Principles and guidelines1 ScopeThis part of ISO 18437 establishes the principles underlying ISO 18437-2 to ISO 18437-5 for the determination of the dynamic mechanical properties (i.e. elastic modulus, shear modulus, bulk modulus, loss factor, and Poisson ratio) of

22、isotropic visco-elastic resilient materials used in vibration isolators from laboratory measurements. It also provides assistance in the selection of the appropriate part of this International Standard.This part of ISO 18437 is applicable to isotropic resilient materials that are used in vibration i

23、solators in order to reduce:a) the transmissions of audio frequency vibrations to a structure that can, for example, radiate fluid-borne sound (airborne, structure-borne or other);b) the transmission of low frequency vibrations which can, for example, act upon humans or cause damage to structures or

24、 sensitive equipment when the vibration is too severe;c) the transmission of shock and noise.The data obtained with the measurement methods that are outlined in this part of ISO 18437 and further specified in ISO 18437-2 to ISO 18437-5 can be used for:1) the design of efficient vibration isolators;2

25、) the selection of an optimum resilient material for a given design;3) the theoretical computation of the transfer of vibrations through vibration isolators;4) information during product development;5) product information provided by manufacturers and suppliers;6) quality control.2 Normative referen

26、cesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 4

27、72, Plastics VocabularyISO 2041, Mechanical vibration, shock and condition monitoring VocabularyISO 4664-1, Rubber, vulcanized or thermoplastic Determination of dynamic properties Part 1: General guidanceISO 6721-1, Plastics Determination of dynamic mechanical properties Part 1: General principlesIS

28、O 10846-2, Acoustics and vibration Laboratory measurement of vibro-acoustic transfer properties of resilient elements Part 2: Direct method for determination of the dynamic stiffness of resilient supports for translatory motionINTERNATIONAL STANDARD ISO 18437-1:2012(E) ISO 2012 All rights reserved 1

29、BS ISO 18437-1:2012ISO 18437-1:2012(E)ISO 23529, Rubber General procedures for preparing and conditioning test pieces for physical test methods3 Terms and definitionsFor the purposes of this part of ISO 18437, the terms and definitions given in ISO 472, ISO 2041, ISO 4664-1, ISO 6721-1, ISO 10846-2,

30、 ISO 23529 and the following apply.3.1Young modulusmodulus of elasticityEratio of the normal stress to linear strainSOURCE: ISO 80000-4:2006,24.1, modified.Note 1 to entry: The Young modulus is expressed in pascals.Note 2 to entry: The complex Young modulus, E*, for a visco-elastic material is repre

31、sented by E* = E + iE, where E is the real (elastic) component of the Young modulus and E is the imaginary (loss modulus) component of the Young modulus. The real component represents elastically stored mechanical energy, while the imaginary component is a measure of mechanical energy loss.3.2loss f

32、actorratio of the imaginary component to the real component of a complex modulusNote 1 to entry: When a material shows a phase difference or loss angle, , between dynamic stress and strain in harmonic deformations, the loss factor is equal to tan .3.3linearityproperty of the dynamic behaviour of a r

33、esilient material if it satisfies the principle of superpositionNote 1 to entry: The principle of superposition is stated as follows: if an input x1(t) produces an output y1(t) and in a separate test an input x2(t) produces an output y2(t), superposition holds if the input x1(t) + x2(t) produces the

34、 output y1(t) + y2(t). This holds for all values of , and x1(t), x2(t); and are arbitrary constants.Note 2 to entry: 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

35、 the dynamic transfer modulus is nominally invariant, the system measurement is considered linear. In effect this procedure checks for a proportional relationship between the response and the excitation.4 Measurement principles4.1 GeneralThe Young modulus of a visco-elastic material is dependent on

36、frequency and temperature. Theoretical details of the various modes of vibration, types of moduli and commonly used test arrangements are well known, are adequately covered in ISO 6721-1 and ISO 4664-1, and are not repeated here. ISO 18437-2 to ISO 18437-4 specify three additional methods that are i

37、n use to obtain the appropriate test data. Because they are complementary with respect to their strong and weak points, they are all described in this part of ISO 18437. In addition, ISO 18437-4 can include the application of static preload. Finally, ISO 18437-5 specifies a method for determining th

38、e Poisson ratio of a material by comparing measurements with finite element calculations. The four methods described here are limited to the measurement of the linear behaviour of materials observed at small strain amplitudes.The conditions for the validity of the measurement methods are:a) linearit

39、y of the vibrational behaviour of the isolator;2 ISO 2012 All rights reservedBS ISO 18437-1:2012ISO 18437-1:2012(E)NOTE The term isolator includes elastic elements with non-linear static load deflection characteristics as long as the elements show approximate linearity for vibration behaviour for a

40、given static preload.b) equal distribution of the interfaces of the vibration isolator with the adjacent source and receiver structures;c) no interaction between the vibration isolator and the surrounding fluid (usually air) medium.It is possible that condition c) is not fulfilled for vibration isol

41、ators made up from an open-cell poro-elastic material, e.g. foam. For frequencies typically greater than 100 Hz, the interaction of the fluid and solid phases of the material can be great enough to modify its rigidity and loss.4.2 Resonance method4.2.1 IntroductionIn the resonance method, the transm

42、issibility (of displacement, velocity or acceleration) of a specimen is measured with the input side driven by a vibration source and the output loaded by a mass. The magnitude and phase information, mass specimen density and length provide the data required to determine the complex Young modulus. F

43、igure 1 shows the principle of the method.4.2.2 Test equipmentThe following test equipment is required:a) electro-dynamic driver;b) accelerometers;c) amplifiers;d) test stand;e) environmental chamber;f) dual-channel spectrum analyser;g) computer.4.2.3 Test specimen preparation and mountingTest speci

44、mens are moulded into the shape of a bar that is typically 100 mm long with cross-sectional dimensions of 6 mm to 7 mm. The specimen cross-section may be square or circular. The length, density and mass of the specimen shall be determined before the specimen is mounted. The specimen is bonded betwee

45、n the mounting blocks, and accelerometers are also bonded as shown in Figure 1. A rigid adhesive such as epoxy or cyanoacrylate is acceptable. The finished assembly is rigidly mounted to the driver so as to produce pure extensional waves in the specimen.4.2.4 Data acquisitionTypically the driver is

46、excited with a random signal; the two-channel spectrum analyser acquires the data and performs a fast Fourier transform (FFT) analysis and averaging. This contains information concerning the mass spring response of the assembly and wave effects in the test specimen. The mass of the mounting block an

47、d specimen length shall be chosen so that the lowest frequency resonance is that of the mass spring system. The lowest frequency resonance shall be clearly separated from the higher frequency wave effects. A typical frequency range is 100 Hz to 5 000 Hz.4.2.5 Analysis of resultsThe real and imaginar

48、y parts of the complex Young modulus are determined from the length, mass, and density of the specimen and from parameters obtained from solutions to the wave equation consisting of two ISO 2012 All rights reserved 3BS ISO 18437-1:2012ISO 18437-1:2012(E)coupled transcendental equations. The solution

49、 is obtained by numerical computation using the NewtonRaphson method at the experimentally determined resonant parameters (i.e. amplitude of the transfer function, frequency and mode number). Details are given in ISO 18437-2.Key1 mounting blocks2 accelerometers3 accelerometer outputs4 test specimen5 direction of vibrationFigure 1 Principle of the resonance method4.3 Cantilever shear beam method4.3.1 IntroductionIn the cantilever shear beam method, a specimen is rigidly mounted at one end and the