1、BRITISH STANDARD BS EN ISO 6721-3:1996 BS2782-3: Method338A: 1996 Plastics Determination of dynamic mechanical properties Part3: Flexural vibration Resonance-curve method The European Standard EN ISO6721-3:1996 has the status of a British Standard ICS 83.080BSENISO6721-3:1996 This British Standard,
2、having been prepared under the directionof the Chemicals and Materials Sector Board, was published under the authority ofthe Standards Board and comesinto effect on 15June1996 BSI 03-2000 The following BSI references relate to the work on this standard: Committee reference PRI/21 Draft for comment 9
3、1/37846 DC ISBN 0 580 25694 4 Committees responsible for this BritishStandard The preparation of this British Standard was entrusted to Technical Committee PRI/21, Testing of plastics, upon which the following bodies were represented: The British Apparel and Textile Confederation British Plastics Fe
4、deration Department of the Environment(Building Research Establishment) Department of Trade and Industry(National Physical Laboratory) Electrical and Electronic Insulation Association(BEAMA Ltd.) GAMBICA(BEAMA Ltd.) Institute of Materials Ministry of Defence Packaging and Industrial Films Associatio
5、n PIRA International RAPRA Technology Ltd. Royal Society of Chemistry Amendments issued since publication Amd. No. Date CommentsBSENISO6721-3:1996 BSI 03-2000 i Contents Page Committees responsible Inside front cover National foreword ii Foreword 2 1 Scope 3 2 Normative reference 3 3 Definitions 3 4
6、 Principle 3 5 Test apparatus 3 6 Test specimens 4 7 Number 4 8 Conditioning 4 9 Procedure 4 10 Expression of results 6 11 Precision 7 12 Test report 7 Annex A (informative) Round-robin testing 8 Annex B (informative) Bibliography 10 Figure 1 Schematic diagrams of test apparatus for methods A and B
7、5 Figure A.1 Real part E 1 fof the flexural complex modulus versus temperature for poly(methyl methacrylate)(PMMA), poly(vinylchloride)(PVC) and polyethylene (PE), measured at300Hz 8 Figure A.2 Real part E 1 fof the flexural complex modulus versus the temperature for poly(methyl methacrylate)(PMMA),
8、 poly(vinylchloride)(PVC) and polyethylene (PE), measured at1000Hz 9 Figure A.3 Flexural loss factor(tan$ f ) versus temperature for poly(methyl methacrylate)(PMMA), poly(vinyl chloride)(PVC) andpolyethylene(PE), measured at300Hz 10 List of references Inside back coverBSENISO6721-3:1996 ii BSI 03-20
9、00 National foreword This British Standard has been prepared by Technical Committee PRI/21 and is the English language version of EN ISO6721-3:1996 Plastics Determination of dynamic mechanical properties Part3: Flexural vibration Resonance curve method. It is identical with ISO6721-3:1994, including
10、 its Technical Corrigendum1: March1995, published by the International Organization for Standardization(ISO). This three part series of standards has been dual-numbered with BS2782 Methods of testing plastics Part 3 Mechanical properties as follows: BS EN ISO6721-1 is designated Method342A. BS EN IS
11、O6721-2 is designated Method342B. BS EN ISO6721-3 is designated Method338A. NOTEInternational and European Standards as well as overseas standards, are available from Customer Services, BSI,389 Chiswick High Road, London, W44AL. A British Standard does not purport to include all the necessary provis
12、ions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-references Publication referred to Corresponding BritishStandard ISO6721-1:1994 BS EN ISO6721 Plastics Det
13、ermination of dynamic mechanical properties BS EN ISO6721-1:1996 General principles Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, theEN title page, pages2 to10, an inside back cover and a back cover. This standard has been updated (see copyright date)
14、 and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO6721-3 February1996 ICS 83.080 Descriptors: Plastics, rigid plastics, tests, vibration tests, determination, mechanical propertie
15、s, dynamic properties, modulus of elasticity, test equipment English version Plastics Determination of dynamic mechanical properties Part3: Flexural vibration Resonance-curve method (ISO6721-3:1994, including Technical Corrigendum1:1995) Plastiques Dtermination des proprits mcaniques dynamiques Part
16、ie3: Vibration en flexion Mthode en rsonance (ISO6721-3:1994, Rectificatif Technique1:1995 inclus) Kunststoffe Bestimmung dynamisch-mechanischer Eigenschaften Teil3: Biegeschwingung Resonanzkurven-verfahren (ISO6721-3:1994, einschlielich Technische Korrektur1:1995) This European Standard was approve
17、d by CEN on1996-01-15. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standar
18、ds may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions(English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the
19、 Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN Euro
20、pean Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1996 Copyright reserved to CEN members Ref. No. EN ISO6721-3:1996 EENISO6721-3:1996 BSI 03-2000 2 Foreword The text of the International Standard
21、from Technical Committee ISO/TC61, Plastics, of the International Organization for Standardization (ISO) has been taken over as a European Standard by Technical Committee CEN/TC249, Plastics, the secretariat of which is held by IBN. This European Standard shall be given the status of a national stan
22、dard, either by publication of an identical text or by endorsement, at the latest by August1996, and conflicting national standards shall be withdrawn at the latest by August1996. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are b
23、ound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom.ENISO6721-3:1996 BSI 03-2000 3 1 Scope This part of ISO6721 specifies a bending
24、-vibration method based upon resonance curves for determining the flexural complex modulus E * fof homogeneous plastics and the damping properties of laminated plastics intended for acoustic insulation, for example systems consisting of a metal sheet coated with a damping plastic layer, or sandwich
25、systems consisting of two sheet-metal layers with an intermediate plastic layer. For many purposes, it is useful to determine these properties as a function of temperature and frequency. 2 Normative reference The following standard contains provisions which, through reference in this text, constitut
26、e provisions of this part of ISO6721. At the time of publication, the edition indicated was valid. All standards are subject to revision, and parties to agreements based on this part of ISO6721 are encouraged to investigate the possibility of applying the most recent edition of the standard indicate
27、d below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO6721-1:1994, Plastics Determination of dynamic mechanical properties Part1: General principles. 3 Definitions SeeISO6721-1:1994, clause 3. NOTE 1As stated in ISO6721-1, frequencies derived from resonanc
28、e curves based on deformation-rate amplitude measurements can be exactly related to dynamic properties. Forthe recommended range of the loss factor of this part of the International Standard, i.e.tan 0,1, resonance curves based upon deformation amplitudes can also be used. For highly damping materia
29、ls, seeISO6721-1:1994, Annex A. 4 Principle A specimen is submitted to forced bending vibrations in the frequency range between about10Hz and1000Hz. The resonance curve(seeISO6721-1:1994, subclause 3.11) is determined and, from the curve obtained, the flexural storage modulus E f (seeISO6721-1:1994,
30、 subclause 3.2) is calculated in the range above0,5MPa and the loss factor given by tan = E f /E f(seeISO6721-1:1994, subclause 3.6) is calculated in the range between about10 2and10 1(seenote1). The test frequency can be varied by making measurements at more than one vibrational order. The measurem
31、ent range for the flexural loss modulus E f (seeISO6721-1:1994, subclause 3.3) is determined by that of the loss factor and by the value of the storage modulus. The mode of oscillation used is designated oscillation mode III (seeISO6721-1:1994, Table2) and the type of modulus measured is designated
32、E f (seeISO6721-1:1994, Table3). The test is performed on rectangular bars, either mounted vertically with the upper end clamped and the other end free(method A) or suspended horizontally by fine fibres at vibrational nodes(method B) (seeFigure 1). Method A is suitable for testing specimens of most
33、types of plastic, including relatively soft materials, whereas method B is particularly suitable for testing rigid(i.e.dimensionally stable) specimens, forexample sheet metal covered by a plastic layer for damping purposes. 5 Test apparatus 5.1 General The apparatus consists of devices for clamping
34、(method A) or suspending(method B) the specimen, electronic devices(frequency generator and recording device) for exciting the specimen to forced bending vibration and for measuring the frequency as well as the velocity amplitude of the specimen(seenote1). For excitation and detection of the vibrati
35、ons two electromagnetic transducers are situated near the ends of the specimen. The specimen, the clamping or supporting device and the electromagnetic transducers are enclosed in a temperature-controlled chamber(seeFigure 1). 5.2 Clamps or suspension fibres If the specimen is clamped at one end, th
36、e clamp shall be designed to hold the upper end of the specimen securely and tightlyseeFigure 1 a). Itshall be constructed so that no additional damping of the system occurs. There are two causes of additional damping: Friction between the test specimen and the clamp: This can be detected by stimula
37、ting freely decaying oscillations of the relevant vibrational order. As explained in ISO6721-1:1994, Annex B, the type of decay is indicative of different types of deviation from linear viscoelastic behaviour. Vibration of the clamp: The clamp shall be rigidly mounted on a heavy mass, which acts as
38、a counterweight to the oscillating test specimen. This requires a heavy rigid stand within the temperature-controlled chamber(seeFigure 1). If the specimen is tested in the horizontal position, it shall be supported by two fine fibres at vibrational nodes(see9.3.2).ENISO6721-3:1996 4 BSI 03-2000 5.3
39、 Exciter and detector The frequency generator shall be capable of exciting the specimen with the aid of the electromagnetic transducer to oscillations within the frequency range of10Hz to1000Hz with a constant force amplitude. The detector shall be capable of measuring the deformation or deformation
40、-rate amplitude(seenote1) of the specimen and the frequency of the oscillation, thereby permitting the recording of the resonance curve (seeISO6721-1:1994, subclause 3.11 and AnnexA). The amplitude of the exciter and the sensitivity of the detector shall not vary with frequency by more than0,5% with
41、in the range of a single-resonance peak, i.e.for any10% variation of the frequency. A tracking filter shall be used to minimize noise at the detector. Frequencies shall be measured with a resolution of at least0,1%(see11.2). Two small, thin steel plates shall be adhesively bonded at the ends of the
42、specimen to permit the excitation and detection of the vibrations by means of suitable electromagnetic transducers(see6.2). 5.4 Temperature-controlled enclosure SeeISO6721-1:1994, subclause 5.3. 5.5 Gas supply Supply of air or other suitable inert gas for purging purposes. 5.6 Temperature-measuremen
43、t device SeeISO6721-1:1994, subclause 5.5. 5.7 Devices for measuring test specimen dimensions and density SeeISO6721-1:1994, subclause 5.6. The balance used for measuring the mass of the specimen shall be capable of weighing to1mg. 6 Test specimens SeeISO6721-1:1994, clause 6. 6.1 Shape and dimensio
44、ns Specimens shall be rectangular bars or strips thick enough to give sufficient bending stiffness, which is critical for the resonance frequency. On the other hand, the thickness shall be sufficiently small when compared to the wavelength of the bending vibration. The specimen thickness shall also
45、be limited to avoid effects due to shear deformation and rotatory inertia if accurate values of E are required. Length-to-thickness ratios of less than50 shall be avoided if values of E are required to be accurate to within 5%, from measurements up to the sixth order of homogeneous, isotropic specim
46、ens. The thickness of the layers of a multilayer system will depend on the purpose for which the system was designed. When comparing various systems by the bending-vibration test, the preferred ratio of the mass of the plastic layer to the mass of the basic sheet material is1:5. The width of the spe
47、cimens shall be less than one-half of the wavelength used in order to avoid lateral resonance vibrations. A width of10mm should be suitable in most cases. The length of the specimens depends on the desired frequency. For specimens clamped at one end, the length shall be sufficiently large to avoid t
48、he clamp influencing the vibration significantly. Usually a free length of180mm will be suitable. If the specimen is not clamped, its length shall be150min. 6.2 Preparation SeeISO6721-1:1994, subclause6.2. Small, thin, light steel plates shall be adhesively bonded to the specimens near their ends to
49、 allow excitation and detection of the vibrations by means of electromagnetic transducers. To avoid errors in E greater than4%, the ratio of the added mass to the specimen mass shall not exceed1%. To avoid the steel plates causing additional stiffness, they shall not extend along more than2% of the length of the specimen. The distance between the steel plates shall be large enough to avoid cross-talk between exciter and detector. Multilayer specimens shall be fabricated with the thickness and by the production techniques
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