ISO 6721-9 AMD 1-2007 Plastics - Determination of dynamic mechanical properties - Part 9 Tensile vibration - Sonic-pulse propagation method Amendment 1 Precisio.pdf

1、 Reference number ISO 6721-9:1997/Amd.1:2007(E) ISO 2007INTERNATIONAL STANDARD ISO 6721-9 First edition 1997-06-01 AMENDMENT 1 2007-11-15 Plastics Determination of dynamic mechanical properties Part 9: Tensile vibration Sonic-pulse propagation method AMENDMENT 1: Precision Plastiques Dtermination de

2、s proprits mcaniques dynamiques Partie 9: Vibration en traction Mthode de propagation de signaux acoustiques AMENDEMENT 1: Fiabilit ISO 6721-9:1997/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 viewe

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7、 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2007 All rights reservedISO 6721-9:1997/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 m

8、ember 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 technical committee has been established has the right to be represented on that committee. International organizations, governm

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11、dies 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 for identifying any or all such patent rights. Amendment 1 to ISO 6721-9:1997 was prepared by Technical Committee ISO/TC 61, Pl

12、astics, Subcommittee SC 2, Mechanical properties. ISO 6721-9:1997/Amd.1:2007(E) ISO 2007 All rights reserved 1 Plastics Determination of dynamic mechanical properties Part 9: Tensile vibration Sonic-pulse propagation method AMENDMENT 1: Precision Page 5, Clause 11 Replace the text of this clause by

13、the following text: The precision of this test method is not known because interlaboratory data are not available due to the difficulty in finding laboratories with test equipment capable of operating at the same frequency. It should be recognized that the properties of thermoplastics are time-depen

14、dent, and the pulse propagation time and hence the dynamic modulus depend closely on the frequency of the sonic pulse used. For information purposes, however, the within-laboratory standard deviation has been determined using data from one laboratory which tested four different materials (see Annex

15、A). Page 8 Add the following annex: ISO 6721-9:1997/Amd.1:2007(E) 2 ISO 2007 All rights reservedAnnex A (informative) Precision A.1 For the reasons outlined in Clause 11, the precision of this method is not known. However, Table A.1 gives repeatability data based on testing performed on identical te

16、st pieces in the same laboratory under the same conditions by the same operator using the same equipment within short intervals of time. It can be seen that a coefficient of variation of up to about 3 % can be expected within a particular laboratory. Table A.1 Repeatability data for tensile storage

17、modulus E measured at 10 kHz Material Average value of E GPa Standard deviation Coefficient of variation % PE-UHMW 1,762 0,009 3 0,53 Polypropylene 2,811 0,054 2 1,93 Uniaxially stretched PP 11,10 0,28 2,5 PEEK 4,232 0,032 8 0,77 A.2 When this method is used with certain materials, consideration sho

18、uld be given to various factors that can lead to a decrease in the repeatability of the measured values. Such factors include the following: a) poor contact between the specimen and the transducers, which may give rise to a low amplitude of the sonic pulse and associated errors in determining the pu

19、lse propagation time; b) anisotropy in the properties of the material, caused by molecular orientation, which will give rise to a dependence of the pulse propagation time on direction in the specimen; c) the presence of filler or reinforcement in the material such that the distribution or orientatio

20、n of the filler or reinforcement affects the pulse propagation time. Note that, since the properties of thermoplastics are time-dependent, the pulse propagation time and hence the dynamic modulus depend closely on the frequency of the sonic pulse used. It is therefore not possible to make accurate comparisons of results obtained using different frequencies. ISO 6721-9:1997/Amd.1:2007(E) ICS 83.080.01 Price based on 2 pages ISO 2007 All rights reserved