1、 ISO 2016 Glass in building Determination of the bending strength of glass Part 1: Fundamentals of testing glass Verre dans la construction Dtermination de la rsistance du verre la flexion Partie 1: Principes fondamentaux des essais sur le verre INTERNATIONAL STANDARD ISO 1288-1 First edition 2016-0
2、2-15 Reference number ISO 1288-1:2016(E) ISO 1288-1:2016(E)ii ISO 2016 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2016, Published in Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means,
3、 electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Ch. de Blandonnet 8 CP 401 CH-121
4、4 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 copyrightiso.org www.iso.org ISO 1288-1:2016(E)Foreword iv 1 Scope . 1 2 Normative references 1 3 T erms and definitions . 1 4 Symbols 2 5 Factors to be taken into account when testing glass . 3 5.1 Glass as a material 3 5.1.1
5、 General 3 5.1.2 Effect of surface condition . 4 5.1.3 Effect of rate of loading 4 5.1.4 Effect of test surface area . 4 5.1.5 Effect of ambient medium 5 5.1.6 Effect of aging . 5 5.1.7 Effect of temperature . 5 5.2 Bending stress and bending strength 5 5.2.1 General 5 5.2.2 Effective stress . 5 5.2
6、.3 Equivalent bending strength . 6 5.2.4 Profile bending strength . 6 5.3 Types of glass . 6 5.3.1 General 6 5.3.2 Patterned glass 6 5.3.3 Laminated glass 6 5.4 Orientation of the specimens . 7 5.5 Number of specimens in a sample . 7 6 Explanations of the test methods 7 6.1 Coaxial double ring test
7、for large test surface areas. 7 6.1.1 Elimination of edge effects 7 6.1.2 Analysis of the stress development . 7 6.1.3 Testing of patterned glass .11 6.2 Test with specimen supported at two points (four point bending) .11 6.1.4 Limitations .11 6.1.5 Inclusion of edge effects .11 6.1.6 Analysis of th
8、e stress development 11 6.3 Coaxial double ring test for small test surface areas .13 6.1.7 Elimination of edge effects .13 6.1.8 Analysis of the stress development 13 7 Range of application of the test methods .14 7.1 General limitations .14 7.2 Limitations to ISO 1288-2 14 7.3 Limitations to ISO 1
9、288-3 14 7.4 Limitations to ISO 1288-4 15 7.5 Limitations to ISO 1288-5 15 8 Calibration of the testing machines .15 9 Recommendations for safe use of test equipment .15 Bibliography .17 ISO 2016 All rights reserved iii Contents Page ISO 1288-1:2016(E) Foreword ISO (the International Organization fo
10、r 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. Each member body interested in a subject for which a technical committee has been established has the
11、 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 (IEC) on all matters of electrotechnical standardization. The proce
12、dures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editoria
13、l rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives). 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. Details of any patent rights
14、identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents). Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement. For an explan
15、ation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information The committee responsible for this docum
16、ent is ISO/TC 160, Glass in building, Subcommittee SC 2, Use considerations. ISO 1288 consists of the following parts, under the general title Glass in building Determination of the bending strength of glass: Part 1: Fundamentals of testing glass Part 2: Coaxial double ring test on flat specimens wi
17、th large test surface areas Part 3: Test with specimen supported at two points (four point bending) Part 4: Testing of channel shaped glass Part 5: Coaxial double ring test on flat specimens with small test surface areasiv ISO 2016 All rights reserved INTERNATIONAL ST ANDARD ISO 1288-1:2016(E) Glass
18、 in building Determination of the bending strength of glass Part 1: Fundamentals of testing glass 1 Scope This part of ISO 1288 specifies the determination of the bending strength of monolithic glass for use in buildings. The testing of insulating units or laminated glass is excluded from this part
19、of ISO 1288. This part of ISO 1288 describes considerations to be taken into account when testing glass, explanations of the reasons for designing different test methods, limitations of the test methods, and gives pointers to safety requirements for the personnel operating the test equipment. ISO 12
20、88-2, ISO 1288-3, ISO 1288-4 and ISO 1288-5 specify test methods in detail. The test methods specified in this part of ISO 1288 are intended to provide large numbers of bending strength values that can be used as the basis for statistical evaluation of glass strength. 2 Normative references The foll
21、owing documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 1288-2, Gla
22、ss in building Determination of the bending strength of glass Part 2: Coaxial double ring test on flat specimens with large test surface areas ISO 1288-3, Glass in building Determination of the bending strength of glass Part 3: Test with specimen supported at two points (four point bending) ISO 1288
23、-4, Glass in building Determination of the bending strength of glass Part 4: Testing of channel shaped glass ISO 1288-5, Glass in building Determination of the bending strength of glass Part 5: Coaxial double ring test on flat specimens with small test surface areas ISO 16293-1, Glass in building Ba
24、sic soda lime silicate glass products Part 1: Definitions and general physical and mechanical properties NOTE ISO TC 160/SC 1 is commencing work on standards for “thermally tempered soda lime silicate safety glass”, “heat strengthened soda lime silicate glass” and “chemically strengthened glass.” 3
25、T erms a nd definiti ons For the purposes of this document, the following terms and definitions apply. ISO 2016 All rights reserved 1 ISO 1288-1:2016(E) 3.1 f la t g la ss any glass product conforming to ISO 16293-2, ISO 16293-3, ISO 16293-4 and ISO 16293-5, or any transformed glass made from these
26、products without deliberately inducing profile or curvature 3.2 bending stress tensile bending stress induced in the surface of a specimen Note 1 to entry: For testing purposes, the bending stress should be uniform over a specified part of the surface. 3.3 effective bending stress weighted average o
27、f the tensile bending stresses, calculated by applying a factor to take into account non-uniformity of the stress field 3.4 bending strength bending stress (3.2) or effective bending stress (3.3) which leads to breakage of the specimen 3.5 equivalent bending strength apparent bending strength (3.4)
28、of patterned glass, for which the irregularities in the thickness do not allow precise calculation of the bending stress (3.2) 3.6 p r o f i l e b e n d i n g s t r e n g t h quotient of the maximum bending moment and the section modulus of a channel shaped glass 3.7 stress intensity factor measure
29、of the stress at a crack tip 3.8 prestressed glass any glass product that has a surface prestress, i.e. thermally tempered soda lime silicate safety glass, heat strengthened soda lime silicate glass and chemically strengthened glass 4 Symbols F applied load N h specimen thickness M L length of side
30、of square test sample M k constant for calculation of bending stress in ISO 1288-3 M K 1 , K 2 constants for calculation of bending stress in ISO 1288-5 M bB maximum bending moment Nm p gas pressure applied within loading ring in ISO 1288-2 Pa P bB profile bending strength (of channel shaped glass)
31、= M bB /Z Pa r 1 radius of loading ring M r 2 radius of supporting ring M2 ISO 2016 All rights reserved ISO 1288-1:2016(E) r 3 radius of circular specimen M r 3m average specimen radius (for evaluation) M y 0 central deflection of specimen M Z section modulus (of channel shaped glass) m 3 poisson nu
32、mber of specimen NOTE For soda lime silicate glass (see ISO 16293-1), a value of 0,23 is used. b bending stress Pa beff effective bending stress Pa bB bending strength Pa beqB equivalent bending strength Pa rad radial stress Pa T tangential stress Pa L stress in a direction along the length of the s
33、pecimen Pa 5 Factors to be taken into account when testing glass 5.1 Glass as a material 5.1.1 General Glass is a homogeneous isotropic material having almost perfect linear-elastic behaviour over its tensile strength range. Glass has a very high compressive strength and theoretically, a very high t
34、ensile strength, but the surface of the glass has many irregularities which act as weaknesses when glass is subjected to tensile stress. These irregularities are caused by attack from moisture and by contact with hard materials (e.g. grit) and are continually modified by moisture which is always pre
35、sent in the air. Tensile strengths of around 10 000 MPa can be predicted from the molecular structure, but bulk glass normally fails at stresses considerably below 100 MPa. The presence of the irregularities and their modification by moisture contributes to the properties of glass which need conside
36、ration when performing tests of strength. Because of the very high compressive strength, glass always fails under tensile stress. Since glass in buildings is very rarely used in direct tension, the most important property for load resistance is the tensile bending strength. All the tests described i
37、n this part of ISO 1288 are intended to evaluate the tensile bending strength of glass. The bending strength is influenced by the following factors: a) surface condition (see 5.1.2); b) rate and duration of loading (see 5.1.3); c) area of surface stressed in tension (see 5.1.4); d) ambient medium, t
38、hrough stress corrosion cracking, as well as healing of surface damage in the glass (see 5.1.5 and Reference 1); ISO 2016 All rights reserved 3 ISO 1288-1:2016(E) e) age, i.e. time elapsing since the last mechanical surface treatment or modification to simulate damage (see 5.1.6); f) temperature (se
39、e 5.1.7). The influence exerted by factors b) to f) on bending strength has been taken into account in this part of ISO 1288. 5.1.2 Effect of surface condition For the purpose of bending strength tests according to this part of ISO 1288, glass behaves as an almost ideally linear-elastic material tha
40、t fails in a brittle manner. This brittleness means that contact with any hard object can lead to surface damage in the form of ultra-fine, partly submicroscopic cracks and chips. Surface damage of this kind, which is practically unavoidable during normal handling of glass, exerts a notch action whi
41、ch is a major factor in reducing mechanical strength, whereas the chemical composition of the glass has only a minor, and in some cases, entirely negligible, significance. Hence, it follows that the bending strength determined by the methods referred to in this part of ISO 1288 is related largely to
42、 the surface condition of the specimen to be tested. This surface condition is characterized by the following main features: a) the surface condition imparted by a particular method of treatment, which produces a specific damage spectrum and thus, results in a strength which is specific to the finis
43、hed surface condition; b) residual stress, e.g. in the form of thermal or chemical prestress intentionally imparted, as well as unintended residual stresses. 5.1.3 Effect of rate of loading For the interpretation of the bending strength values determined as described in this part of ISO 1288, the ra
44、te of loading is of special importance. Cracks propagate in glass over a wide range of values of tensile stress (see Reference 2). There is a lower limit to the stress intensity factor below which cracks do not propagate (see Reference 1). There is then some subcritical crack propagation at higher l
45、evels of stress intensity factor, which is influenced by humidity, temperature and chemical agents. Above a critical stress intensity factor, crack propagation is very rapid and leads to (almost) instantaneous failure. The consequence of the subcritical crack propagation is, for example, that the ra
46、te of load increase and/or the duration of static loading influences the bending strength. For prestressed glass, this time dependence does not manifest itself until the tensile stress induced in the surface exceeds the compressive stress permanently present there (see Reference 3). 5.1.4 Effect of
47、test surface area The decrease in bending strength of glass with increasing size of the test area exposed to high stress is also of importance (see Reference 4). This area effect is accounted for by the statistical distribution of surface defects varying in effectiveness; the larger the test area, t
48、he greater is the probability of its containing a large surface defect. Consequently, the influence of the area effect increases with decreasing incidence of defects in the surface, so that this influence is more pronounced in the case of undamaged, e.g. fire-finished glass surfaces (see Reference 5
49、). Differences are likely between the mean values of the bending strength as measured in accordance with ISO 1288-2 (maximally stressed area: 240 000 mm 2 ), or by using devices R105, R60, R45 and R30 in accordance with ISO 1288-5 (maximally stressed areas: 3 850 mm 2 , 1 260 mm 2 , 254 mm 2and 113 mm 2 ), due to the size of the stressed area. Depending on surface damage, the results obtained from testing smaller surface areas may be significantly higher than those obtained from t
