ISO-7854-1995.pdf
《ISO-7854-1995.pdf》由会员分享,可在线阅读,更多相关《ISO-7854-1995.pdf(16页珍藏版)》请在三一文库上搜索。
1、INTERNATIONAL STANDARD ISO 7854 Second edition 1995-08-15 Rubber- or plastics-coated fabrics - Determination of resistance to darnage by flexing Supports textiles rev6tus de caoutchouc ou de plastique - Determination de Ia rdsistance 2 Ia flexion Reference number ISO 7854:1995(E) ISO 7854:1995(E) Fo
2、reword 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 out through ISO technical committees. Esch member body interested in a subject for which a tec
3、hnical 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 International Electrotechnical Commission (1 EC) on all matters
4、of electrotechnical standardization. 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. International Standard ISO 7854 was
5、prepared by Technical Committee ISOJTC 45, Rubber and rubber products. This second edition cancels and replaces the first edition (ISO 7854: 1984), which has been technically revised. Annex A of this International Standard is for information only. 0 ISO 1995 All rights reserved. Unless otherwise spe
6、cified, no part of this publication may be reproduced or utilized in any form or by any means, electronie or mechanical, including photocopying and mrcrofilm, without permission in writing from the publisher. International Organization for Standardization Case Postale 56 l CH-l 211 Geneve 20 l Swi t
7、zerlan d Printed in Switzerland 0 ISO ISO 7854: 1995(E) Introduction Investigation of dynamic-flex fatigue properties of coated fabrics has for a number of years suffered from poor repeatability (due in part to the un- known but inevitable variability of the material tested) and worse reproducibilit
8、y. Nevertheless, dynamic-flex performante of coated fabrics has been long and widely used as a measure of the product quality. The methods traditionally used suffered from the common deficiency of testing only a small test piece. The De Mattia test is unsuitable for ma- terials that exhibit “Set”, s
9、uch as thermoplastics, and the Schildknecht method has disadvantages when testing the heavier industrial fabrics and also tends to require very high geometric ratios and consequently time- consuming tests to verify results. In addition, the mounting of Schildknecht test pieces tan seriously affect t
10、est results and repeatability. Both the De Mattia and Schildknecht methods are also uni-directional, which in some cases is advantageous, but in many cases is not appropri- ate, e.g. where bi-directional Stresses are exerted during use. This revised edition of ISO 7854 attempts to standardize the mo
11、unting difficulties associated with the Schildknecht apparatus (method B) and in- troduces a bi-directional flex fatigue test that provides a large test piece, enabling post-flexing investigations, such as hydrostatic-head tests, to be conducted. The apparatus is described in ISO 8096-3:1988, Rubber
12、- or plas tics-cos ted fabrics for wa ter-resis tan t clo thing - Specifica tion - Part 3: Natura/ rubber- and synthetic rubber-coated fabrics. The apparatus outlined there in illustrative form (see the note to F.l in annex F of ISO 8096-3:1988) has been developed in more detail and is now widely av
13、ailable commercially from a number of sources. Flex testing tan provide a useful indication of the durability of coated fab- ries. However, for most applications, flexing conditions induced by these test methods are dissimilar to the conditions met in practice. In particular, the micro-climate induc
14、ed around the test piece and the thermal Stresses induced in the molecular structure of the coating during flexing are unlikely to be representative of practical situations. lt is important therefore that these effects be kept to a minimum and their effect be given due con- sideration when test resu
15、lts are being considered. Consequently, it is im- portant to ensure that the air temperature around the test pieces is kept constant during the test. This tan be achieved either by maintaining ade- quate non-forced, open Ventilation around the test pieces or by controlling the air temperature within
16、 any closed Container in which the test apparatus may be mounted. Three methods are described. Method A (De Mattia) may be found suit- able for flex testing coated fabrics which cannot be constrained into the configuration required by method B or where the amount of material available for testing is
17、 too small to permit the other methods to be em- ployed. Method B (Schildknecht) will be found useful for flex testing coated fabrics of relatively lightweight construction or whose practical ISO 7854: 1995(E) 0 ISO usage would be in the light to medium range in flexing. terms of severity of Method
18、C (crumple/flex test) has been found useful in testing coated fabrics which will be subject to severe usage in terms of their flexing ca- pability under arduous conditions. The method requires a large test piece but this provides certain advantages for selecting test pieces for related testing after
19、 flexing, e.g. hydrostatic-head testing. Some coated fabrics are the wet state and attent more on IS susceptible to delaminat ion when f lexed drawn to the information given in annex in A . Because of the differentes in the nature of the flexing in the three methods, no true correlation of results b
20、etween the different methods is possible. iv INTERNATIONAL STANDARD 0 ISO ISO 7854:1995(E) Rubber- or plastics-coated fabrics - Determination of resistance to darnage by flexing 1 Scope tween a pair of flat grips, one of which reciprocates, causing the folded test piece to be bent outwards five This
21、 International Standard describes three methods times per second. This high-speed folding of the test of assessing the resistance of coated fabrics to dam- piece is continued for either a pre-set number of cy- age by repeated flexing. cles or until darnage to the test piece is apparent. 2 Normative
22、references 3.2 Apparatus The following Standards contain provisions which, through reference in this text, constitute provisions of this lnternational Standard. At the time of publi- cation, the editions indicated were valid. All Standards are subject to revision, and Parties to agreements based on
23、this International Standard are encouraged to investigate the possibility of applying the most re- cent editions of the Standards indicated below. Members of IEC and ISO maintain registers of cur- rently valid International Standards. 3.21 Flex-testing machine, as specified in ISO 132, with pairs of
24、 flat grips. One of the grips of each pair is capable of a reciprocating motion in a vertical plane with a stroke length of (57 +it5) mm and a frequency of 5,0 Hz + 0,2 Hz. - Esch pair of grips is positioned so that they are 70 mm + 1 mm apart when in the open Position and - 13 mm + 0,5 mm apart whe
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- ISO 7854 1995
链接地址:https://www.31doc.com/p-3779442.html