1、 Reference number ISO 6721-7:1996/Amd.1:2007(E) ISO 2007INTERNATIONAL STANDARD ISO 6721-7 First edition 1996-06-01 AMENDMENT 1 2007-02-01 Plastics Determination of dynamic mechanical properties Part 7: Torsional vibration Non-resonance method AMENDMENT 1 Plastiques Dtermination des proprits mcanique
2、s dynamiques Partie 7: Vibration en torsion Mthode hors rsonance AMENDEMENT 1 ISO 6721-7:1996/Amd.1:2007(E) 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 unless the typefaces which a
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7、SO 2007 All rights reservedISO 6721-7:1996/Amd.1:2007(E) ISO 2007 All rights reserved iii Foreword 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 ou
8、t through ISO technical 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 organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO co
9、llaborates closely with the International 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
10、Standards. Draft International Standards 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 element
11、s of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Amendment 1 to ISO 6721-7:1996 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 2, Mechanical properties. ISO 6721-7:1996/Amd.1:2007(E) ISO
12、 2007 All rights reserved 1 Plastics Determination of dynamic mechanical properties Part 7: Torsional vibration Non-resonance method AMENDMENT 1 Page 1, Clause 1 Replace the first paragraph by the following (grey shading indicates new text): “This part of ISO 6721 describes a torsional, non-resonanc
13、e method for determining the components of the shear complex modulus G* of solid polymers in the form of bars or rods at frequencies typically in the range 0,001 Hz to 100 Hz. Higher-frequency measurements can be made, but significant errors may be obtained in the dynamic properties measured (see 10
14、.2.1 and 10.2.2). The method is suitable for measuring dynamic storage moduli ranging from about 10 MPa, which is typical of values obtained for stiff rubbers, to values of about 10 GPa which are representative of fibre-reinforced plastics. Although materials with moduli less than 10 MPa may be stud
15、ied, more accurate measurements of their dynamic properties can be made using simple shear (see ISO 6721-6) or torsional deformations of thin layers between parallel plates.” Page 3, Subclause 9.5 Replace Note 4 by the following paragraph (grey shading indicates new text): “If the maximum shear stra
16、in within the specimen exceeds the limit for linear behaviour, then 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
17、. The dynamic strain range for linear behaviour can be explored by varying the dynamic displacement amplitude at a constant frequency and recording any change in dynamic stiffness with strain amplitude. A low frequency should be used for this purpose to minimize any temperature increase caused by me
18、chanical loss. However, it should be noted that, because of the non-uniform strain in the specimen in this test, the onset of non-linear behaviour will be less apparent than in tests where the strain distribution is uniform. If non-linear behaviour is detected in the strain range of interest, the dynamic strain limit shall be recorded in the test report.” ISO 6721-7:1996/Amd.1:2007(E) ICS 83.080.01 Price based on 1 page ISO 2007 All rights reserved
