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1、IS0 b721-5 96 4851903 Obb2004 777 m INTERNATIONAL STANDARD IS0 6721-5 First edition 1996-05-1 5 Plastics - Determination of dynamic mechanical properties - Part 5: Flexural vibration - Non-resonance method Plastiques - Dtermination des proprits mcaniques dynamiques - Partie 5: Vibration en flexion -
2、 Mthode hors rsonance This material is reproduced from IS0 documents under International Organization for Standardization (ISO) Copyright License number IHSllCC11996. Not for resale. No part of these IS0 documents may be reproduced in any form, electronic retrieval system or otherwise, except as all
3、owed in the copyright law of the country of use, or with the prior written consent of IS0 (Case postale 56,1211 Geneva 20, Switzerland, Fax +4122 734 10 79), IHS or the IS0 Licensors members. Reference number IS0 6721-5:1996(E) COPYRIGHT International Organization for Standardization Licensed by Inf
4、ormation Handling Services COPYRIGHT International Organization for Standardization Licensed by Information Handling Services IS0 6721-5 7b = 4853703 0662005 bo3 W IS0 6721 -5:1996( E) Foreword IS0 (the International Organization for Standardization) is a worldwide fed- eration of national standards
5、 bodies (IS0 member bodies). The work of preparing International Standards is normally carried out through IS0 tech- nical committees. 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 organi
6、zations, governmental and non- governmental, in liaison with ISO, also take part in the work. IS0 collabor- ates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are
7、cir- culated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard IS0 6721-5 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 2, Mechanical properties. - Part 1
8、: General principles - Part 2: Torsion-pendulum method - Part 3: Flexural vibration - Resonance-curve method - Part 4: Tensile vibration - Non-resonance method - Part 5: Flexural vibration - Non-resonance method - Part 6: Shear vibration - Non-resonance method - Part 7: Torsional vibration - Non-res
9、onance method - Part 8: Longitudinal and shear vibration - Wave-propagation method - Part 9: Tensile vibration - Sonic-pulse propagation method - Part 10: Dynamic shear viscosity using a parallel-plate oscillatory rheometer O IS0 1996 All rights reserved. Unless otherwise specified, no part of this
10、publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher. International Organization for Standardization Case postale 56 CH-1 21 1 Genve 20 Switzerland . Printed in Switzerl
11、and II COPYRIGHT International Organization for Standardization Licensed by Information Handling Services COPYRIGHT International Organization for Standardization Licensed by Information Handling Services IS0 b72L-5 96 m 4853903 Ob62006 54T m INTERNATIONAL STANDARD Q IS0 IS0 6721 -5 1996() Plastics
12、- Determination of dynamic mechanical properties - Part 5: Flexural vibration - Non-resonance method 1 Scope This part of IS0 6721 describes a flexural, non- resonance method for determining the components of the Youngs complex modulus E* of polymers at fre- quencies typically in the range 0,Ol Hz t
13、o 100 Hz. The method is suitable for measuring dynamic storage moduli in the range 10 MPa to 200 GPa. Although materials with moduli less than 10 MPa may be studied, more accurate measurements of their dy- namic properties can be made using shear modes of deformation (see part 6 of IS0 6721 1. This
14、method is particularly suited to the measurement of loss factors greater than 0,l and may therefore be conveniently used to study the variation of dynamic properties with temperature and frequency through most of the glass-rubber relaxation region (see IS0 6721-1 :1994, subclause 9.4). The availabil
15、ity of data determined over wide ranges of both frequency and temperature enables master plots to be derived, using frequency/temperature shift procedures, which present dynamic properties over an extended fre- quency range at different temperatures. 2 Normative references The following standards co
16、ntain provisions which, through reference in this text, constitute provisions of this part of IS0 6721. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this part of IS06721 are encouraged to investigate the poss
17、ibility of applying the most recent editions of the standards indicated below. Members of IEC and IS0 maintain registers of currently valid International Standards. IS0 6721-1 :1994, Plastics - Determination of dy- namic mechanical properties - Part I: General prin- ciples. IS0 6721-6:1996, Plastics
18、 - Determination of dy- namic mechanical properties - Part 6: Shear vibration - Non-resonance method. 3 Definitions See IS0 6721-1 :1994, clause 3. 4 Principle A test specimen is subjected to a sinusoidal trans- verse force or displacement at a frequency signifi- cantly below the fundamental flexura
19、l resonance fre- quency (see 10.2.11. The amplitudes of the force and displacement cycles applied to the specimen and the phase angle between these cycles are measured. The storage and loss components of the Youngs complex modulus and the loss factor are calculated using equations given in clause 10
20、 of this part of IS0 6721. 5 Apparatus 5.1 Loading assembly The requirements for the loading assembly are that it shall permit measurements of the amplitudes of, and phase angle between, the force and displacement cycles for a specimen subjected to a transverse sinus- oidal force or displacement. Va
21、rious designs of appar- atus are possible, as illustrated schematically in figures 1 and 2. In figure la), a sinusoidal displace- ment is generated by the vibrator V and applied to the specimen S through moving clamps C1 located close to the opposite ends of the specimen. The amplitude and frequency
22、 of the vibrator table displacement are variable and monitored by the transducer D. The specimen is held at its centre by a fixed clamp C2 and thus undergoes sinusoidal flexural deformations. The sinusoidal force applied in deforming the specimen is 1 COPYRIGHT International Organization for Standar
23、dization Licensed by Information Handling Services COPYRIGHT International Organization for Standardization Licensed by Information Handling Services - IS0 6723-5 9b 4853903 Ob62007 486 - IS0 6721 -5:1996(E) monitored by a force transducer F connected to C2. The members between the clamps C l and V,
24、 and between C2 and F, shall be much stiffer than the specimen and shall have a low thermal conductance if the specimen is to be enclosed in a temperature- controlled cabinet. NOTE 1 Whilst each member of the loading assembly may have a much higher stiffness than the specimen, the presence of clampe
25、d or bolted connections can signifi- cantly increase the apparatus compliance. It may then be necessary to apply a compiiance correction as described in 10.2.3. Various other loading assemblies may be employed as alternatives to that detailed above. For example, the specimen may be simply supported
26、and deformed in three-point flexure, as illustrated in figure 1 b). Fur- thermore, the force on the specimen may be calcu- lated from the current supplied to the vibrator, thus eliminating the need for a separate force transducer. With this method (see figure 21, it should be recog- nized that part
27、of the force generated by the vibrator current is used to accelerate the drive shaft and to deform the drive-shaft suspension Su in parallel with the specimen. That part of the generated force used to deform the specimen must be determined with the Q IS0 5.1.2 Transducers The term transducer in this
28、 part of IS0 6721 refers to any device capable of measuring the applied force or displacement, or the ratio of these quantities, as a function of time. The calibration of the transducers shall be traceable to national standards for the measurement of force and length. The calibration shall be accura
29、te to I 2 YO of the minimum force and dis- placement cycle amplitudes applied to the specimen for the purpose of determining dynamic properties. 5.2 Electronic data-processing equipment Data-processing equipment shall be capable of record- ing the force and displacement cycle amplitudes to an accura
30、cy o f f 1 %, the phase angle between the force and displacement cycles to an accuracy of f0.1“ and the frequency to an accuracy o f f 10 YO. 5.3 Temperature measurement and control See IS0 6721-1:1994, subclauses 5.3 and 5.5. aid of a seprate calibration with the specimen absent. 5.4 Devices for me
31、asuring test specimen dimensions 5.1.1 Load stage See IS0 6721-1 :1994, subclause 5.6. The clamps shall be capable of gripping the test specimen with a force which is sufficient to prevent the specimen from slipping during the flexural defor- mation, and to maintain the force at low tempera- tures.
32、6 Test specimens See IS0 6721-1:1994, clause 6. With the simply supported specimen figure 1 bil, the supporting rollers shall contact the specimen along parallel lines and have radii sufficiently large to avoid significant indentation of the specimen and thereby minimize consequent errors in the mea
33、sured moduli and loss factors. The separation between the two outer clamps and between the outer supports shall be variable so that specimens of different length can be accommodated and length corrections may be determined for the clamped specimens (see 10.2.4). A facility to permit small variations
34、 in the clamp separation figure 1 a) would also allow for thermal expansion of the speci- mens and is necessary to avoid errors in the apparent moduli due to buckling of the specimens at high tem- peratures. Any misalignment of the load stage with respect to the force transducer will produce a later
35、al component of the force applied to the transducer during loading of the specimen. The alignment of the loading assembly and test specimen shall be such that any lateral com- ponent recorded by the transducer is less than 1 YO of the longitudinal force. 6.1 Shape and dimensions Test specimens of re
36、ctangular cross-section are rec- ommended to facilitate load introduction. The width and thickness shall not vary along the specimen length by more than 2 % of the mean value. The di- mensions of the specimens are not critical although, for isotropic materials, values of Laid 16 for clamped specimen
37、s and L,/d 8 for simply supported speci- mens would make corrections for shear deformation negligible (see 1 O. 1 and 10.2). Also values of La/b 6 for clamped specimens and L,/b 3 for simply sup- ported specimens are recommended to avoid signifi- cant errors associated with constraints to defor- mat
38、ions along the width direction (anticlastic curva- ture) near to the clamps or central support (see 10.1). For test conditions under which the storage moduli are high (a 50 GPa), sufficiently long, thin specimens shall be employed so that displacements are gener- ated that may be measured with high
39、accuracy. Alter- natively, when the storage moduli are low (c 100 MPa), relatively short, thick specimens may be required to achieve sufficient accuracy in the measurement of force. 2 COPYRIGHT International Organization for Standardization Licensed by Information Handling Services COPYRIGHT Interna
40、tional Organization for Standardization Licensed by Information Handling Services Q IS0 IS0 6723-5 96 m 4851903 Obb2008 312 m IS0 6721-5:1996(E) NOTE 2 A variation in dynamic properties may be ob- served between specimens of different thickness prepared by injection moulding owing to differences whi
41、ch may be present in the structure of the polymer in each specimen. 6.2 Preparation See IS0 6721-1:1994, subclause 6.2. maintain the load under the decreasing part of the superimposed dynamic load. NOTE 4 If the maximum tensile strain within the speci- men exceeds the limit for linear behaviour, the
42、n the derived dynamic properties will depend on the magnitude of the applied displacement. The limiting strain varies with the composition of the polymer and the temperature, and is typically in the region of 0,2 % for glassy plastics. 7 Number of specimens See IS0 6721-1:1994, clause 7. 8 Condition
43、ing See IS0 6721 -1 :1994, clause 8. 9 Procedure 9.1 Test atmosphere See IS0 6721-1:1994, subclause 9.1. 9.2 Measuring the cross-section of the specimen See IS0 6721-1:1994, subclause 9.2. 9.3 Clamping the specimen Record the amplitudes of, the phase difference be- tween and the frequency of the for
44、ce and displace- ment signals, as well as the temperature of the test. Where measurements are to be made over ranges of frequency and temperature, it is recommended that the lowest temperature be selected first and measurements made with increasing frequency, keeping the temperature constant. The fr
45、equency range is then repeated at the next higher temperature (see IS0 6721-1:1994, subclause 9.4). For those test conditions under which the polymer exhibits medium or high loss (for example in the glass-rubber transition region), the energy dissipated by the polymer may raise its temperature suffi
46、ciently to give a significant change in dynamic properties. Any temperature rise will increase rapidly with increasing strain amplitude and frequency. If the data-processing electronics is capable of analysing the transducer outputs within the first few cycles, then the influence of any temperature
47、rise will be minimized. Subse- quent measurements will then change with time as the specimen temperature continues to rise, and such observations will indicate the need to exercise some caution in the presentation and interpretation of results. Mount the specimen between the clamps, using a clamping
48、 force that is sufficient to prevent slip under all test conditions. If measurements are observed to i of results depend upon clamp pressure, then a constant press- ure shall be used for all measurements, especially when applying a length correction (see 10.2.4 and note 3). b specimen width, in metr
49、es 10.1 Symbols d NOTE3 If measurements are observed to depend upon specimen thickness, in metres E;, E E“ apparent and corrected Youngs storage modulus, in pascals Youngs loss modulus, in pascals 9.4 Varying the temperature f measurement frequency, in hertz clamp pressure, then the clamped area of the specimen is probably too small. A larger clamp face or a wider specimen should eliminate this problem. See IS0 6721-1 :1994, subclause 9.4. 9.5 Performing the test f F resonance frequency, in hertz, of the force transducer fs resonance frequency, in hertz, of the sp