1、BRITISH STANDARD BS 7604-1: 1992 ISO 10345-1: 1992 Method for Determination of stress-optical coefficient of glass Part 1: Tensile testBS7604-1:1992 This British Standard, having been prepared under the directionof the Laboratory Apparatus Standards Policy Committee, was published underthe authority
2、 of the Standards Boardand comes into effect on 15 September 1992 BSI 09-1999 The following BSI references relate to the work on this standard: Committee reference LBC/8 Draft for comment 90/53965 DC ISBN 0 580 21159 2 Committees responsible for this British Standard The preparation of this British
3、Standard was entrusted by the Laboratory Apparatus Standards Policy Committee (LBC/-) to Technical Committee LBC/8, upon which the following bodies were represented: British Glass Manufacturers Confederation Society of Glass Technology Amendments issued since publication Amd. No. Date CommentsBS7604
4、-1:1992 BSI 09-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope 1 2 Definition 1 3 Principle 1 4 Apparatus 1 5 Test specimens 1 6 Procedure 2 7 Expression of results 3 8 Test report 3 Annex A (informative) Bibliography 4 Figure 1 Test specimen with holes 2
5、List of references Inside back coverBS7604-1:1992 ii BSI 09-1999 National foreword This British Standard has been prepared under the direction of the Laboratory Apparatus Standards Policy Committee. It is identical with ISO 10345-1:1992 Glass Determination of stress-optical coefficient Part 1: Tensi
6、le test, published by the International Organization for Standardization (ISO). It has been prepared by Subcommittee 5, Quality of glassware, of Technical Committee48, Laboratory glassware and related apparatus, with the active participation and approval of the United Kingdom. This British Standard
7、describes a method of test only and should not be used or quoted as a specification defining limits of performance. Reference to this British Standard should indicate that the method of test used is in accordance with BS7604-1:1992. A British Standard does not purport to include all the necessary pr
8、ovisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1 to 4,
9、an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS7604-1:1992 BSI 09-1999 1 1 Scope This part of ISO 10345 describes the tensile test for deter
10、mining the stress-optical coefficient of isotropic glass. The stress-optical coefficient is a characteristic value of materials and it is necessary for determining the stress from the results of measurement of stress birefringence. 2 Definition For the purposes of this part of ISO 10345, the followi
11、ng definition applies. 2.1 stress-optical coefficient ratio of birefringence effect to applied uniaxial stress on an optical material. ISO 98021 where NOTE 1The stress-optical coefficient is a function of the wavelength. It can be either positive or negative. 3 Principle Uniaxial loading of the test
12、 specimen in the tensile test and stress-optical measurement of the optical path difference at the centre of the test specimen. NOTE 2The stress-optical coefficient can also be determined by a compressive test if bend stress and shear stress are sufficiently insignificant (see 4.2 and 6.3). The dire
13、ction of the testing force is then opposite to that of the tensile test and the compensator shall be applied after being turned through 90 . 4 Apparatus 4.1 Device for measuring the height of the test specimen, to the nearest 0,01 mm. 4.2 Apparatus, consisting of stressing equipment including force
14、measuring device and polarization measuring equipment with compensator The stressing equipment shall allow the application of an uniaxial tensile load to the vertically arranged test specimen across the measuring area (see Figure 1). The test specimen shall not be loaded simultaneously by shearing a
15、nd bending. The force measuring device shall be capable of determining the testing forces to an accuracy of 1 %. The design of the stressing equipment and test specimen holding device shall allow the tensile axis to be aligned with the axis of the test specimen during the test. The polarization meas
16、uring equipment shall allow the measurement of the optical path difference with the compensator to 5 nm. The light source shall be white light with a corresponding interference filter for the wavelength of 589,3 nm. The stressing equipment and the polarization measuring equipment shall be reciprocal
17、ly adjustable in both the horizontal and vertical directions, so that the centre of the test specimen is located in the viewing axis of the polarization measuring equipment. The subtraction position of the compensator of the polarization measuring equipment shall be determined using a glass for whic
18、h the sign of the stress-optical coefficient is known. 5 Test specimens 5.1 Dimensions of the test specimens Over the total length of the test specimen (seeFigure 1), the rectangular cross-section (b h) shall be at least 25 mm 2and the length l, atleast50mm. The breadth b and the height h shall be n
19、ot less than 4 mm. In addition, the test specimen shall be straight. If the test specimen is to be held by steel pivots set in holes, the height h and the breadth b of the test specimen shall be not less than 6 mm. The distances between the holes and the upper and lower surfaces of the test specimen
20、 shall be at least 6 mm. . . . (1) K is the stress-optical coefficient; %s is the optical path difference; a is the light path in the test specimen (which is identical with the breadth b of the test specimen); is the tensile or compressive stress.BS7604-1:1992 2 BSI 09-1999 If the test specimen is h
21、eld in the stressing equipment by bonding its upper and lower surfaces, these surfaces shall be normal to the axis of the test specimen and nearly plane-parallel. Small deviations from plane-parallelism are compensated by hardened adhesive remaining between the test specimen holding device and the u
22、pper and lower surfaces of the test specimen. For good bonding, the upper and lower surfaces of the test specimen should be rough-ground. 5.2 Condition of the test specimens The test specimen shall not have inhomogeneously distributed residual stresses. Homogeneously distributed residual stresses sh
23、ould be lower than1% of the measuring value. The surfaces of the test specimen for light transmission, with areas of (l h), shall be ground and polished in such a way that the measurement of the optical path difference is not interfered with by surface roughness. The surfaces of the test specimen, w
24、ith areas of(l b), shall be at least fine-ground. 6 Procedure 6.1 Take all measurements at room temperature between 15 C and 35 C. Any temperatures differing from this value shall be stated in the test report. 6.2 Measure the height h of the test specimen at the measuring surface, to the nearest 0,0
25、1 mm. NOTE 3It is not also necessary to measure the breadth b of the test specimen, because it is not needed for the calculation of the stress-optical coefficient according to equation (2). Figure 1 Test specimen with holesBS7604-1:1992 BSI 09-1999 3 6.3 Mount the test specimen in the stressing equi
26、pment in such a way that the axis of the test specimen is in line with the tensile axis and that any bending and shearing load is excluded at the measuring surface (see 6.4 and Figure 1). This requirement is considered to be fulfilled when a gradient of birefringence does not exist in this region in
27、 the horizontal direction. 6.4 In the vertical direction, the distance between the point of polarizing optical measurement and the centre of the test specimen shall be not more than10mm. In the horizontal direction, this distance shall be not more than a quarter of the height of the test specimen (a
28、lso see the measuring surface in Figure 1). 6.5 When the light passes through the test specimen in a perpendicular direction, measure the optical path difference of the birefringence at the measuring surface (see Figure 1), twice for each of at least two testing forces to be applied. Use testing for
29、ces of more than 100 N which shall differ by more than 200 N. The direction of light transmission shall be perpendicular to the stressing direction of the testing force and parallel to the end faces of the test specimen. For test specimens with striae or other inhomogeneities, three different testin
30、g forces should be applied for the determination of the optical path difference. 7 Expression of results Calculate the stress optical coefficient K according to the numerical equation (2): where When the optical path differences have been measured with more than two testing forces, the stress-optica
31、l coefficient should be determined from the measuring values using a graph or by calculation. 8 Test report The test report shall include the following information: a) reference to this part of ISO 10345; b) type and designation of the glass tested; c) wavelength of the light source, if 589,3 nm was
32、 not used; d) testing temperature, if outside the range 15 C to 35 C; e) stress-optical coefficient, expressed in 10 6mm 2 /N to the nearest 0,05.10 6mm 2 /N. . . . (2) K is the stress-optical coefficient, expressed in 10 6mm 2 /N; h is the height of the test specimen, in millimetres; F 1and F 2are
33、the testing forces, in newtons; %s 1 is the optical path difference with testing force F 1in nanometres; %s 2 is the optical path difference with testing force F 2in nanometres.BS7604-1:1992 4 BSI 09-1999 Annex A (informative) Bibliography 1 ISO 9802:, Raw optical glass Vocabulary 1) . 1) To be publ
34、ished.BS7604-1:1992 BSI 09-1999 List of references See national foreword.BS 7604-1: 1992 ISO 10345-1: 1992 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the UK view on standards in
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