ISO 16572-2008 Timber structures - Wood-based panels - Test methods for structural properties《木结构 木基板材 结构性能的试验方法》.pdf

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1、 Reference number ISO 16572:2008(E) ISO 2008INTERNATIONAL STANDARD ISO 16572 First edition 2008-06-01 Timber structures Wood-based panels Test methods for structural properties Structures en bois Panneaux base de bois Mthodes dessai pour la dtermination des proprits structurelles ISO 16572:2008(E) P

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5、HT PROTECTED DOCUMENT ISO 2008 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or

6、 ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2008 All rights reservedISO 16572:2008(E) ISO 2008 All rights reserved iii Co

7、ntents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references . 1 3 Terms and definitions. 1 4 Symbols and abbreviated terms . 2 5 Sampling 3 5.1 Sampling of panels. 3 5.2 Sampling of specimens 3 6 Preparation of test pieces 4 6.1 Conditioning 4 6.2 Dimensions of test pieces . 4 6.3 Mois

8、ture content. 4 6.4 Density . 4 7 Bending properties. 5 7.1 True bending properties flatwise 5 7.2 Apparent bending properties flatwise 7 7.3 Bending properties edgewise 8 8 Compression properties 10 8.1 General. 10 8.2 Compression test for small test pieces 10 8.3 Compression test for large-size te

9、st pieces 12 8.4 Expression of results . 14 9 Tension properties 14 9.1 Test piece 14 9.2 Loading equipment. 14 9.3 Loading method 15 9.4 Test procedure 15 9.5 Expression of results . 15 10 Panel shear 16 10.1 Panel shear Method A 16 10.2 Panel shear Method B 17 10.3 Expression of results . 20 11 Pl

10、anar shear 20 11.1 Method A Loaded by plates 20 11.2 Method B Five-point bending 23 12 Test report . 24 12.1 General. 24 12.2 General data 24 12.3 Data on the material 24 12.4 Data on individual test pieces . 25 12.5 Data on physical properties. 25 12.6 Additional information 25 12.7 Sampling data .

11、 25 Annex A (informative) Small-size compression test pieces 26 Annex B (informative) Example of cutting schedule 27 Annex C (informative) Panel shear Method B. 28 ISO 16572:2008(E) iv ISO 2008 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwide federa

12、tion 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 right to be represented on that committ

13、ee. 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. International Standards are drafted in accordance

14、 with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires ap

15、proval by at least 75 % of the member bodies 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. ISO 16572 was prepared by Technical Comm

16、ittee ISO/TC 165, Timber structures. ISO 16572:2008(E) ISO 2008 All rights reserved v Introduction For each type and grade of panel product, as defined (for example in a wood-based panel standard), it is necessary to determine characteristic values of structural properties to enable it to be used fo

17、r structural purposes. This International Standard details the necessary testing, which may only need to be carried out once for each type and grade of product unless there is a reason to suspect a significant change has occurred in its properties. This International Standard is not intended for qua

18、lity control testing. INTERNATIONAL STANDARD ISO 16572:2008(E) ISO 2008 All rights reserved 1 Timber structures Wood-based panels Test methods for structural properties 1 Scope This International Standard specifies test methods for determining the structural properties of commercial wood-based and l

19、ignocellulosic fibrous panel products for use in load-bearing timber structures. These properties are intended for the calculation of characteristic values. NOTE Bamboo is an example of a lignocellulosic fibrous material. 2 Normative references The following referenced documents are indispensable fo

20、r the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 9424, Wood-based panels Determination of dimensions of test pieces ISO 9427, Wood-based panels Deter

21、mination of density ISO 16979, Wood-based panels Determination of moisture content 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 knife check separation of the fibres which does not extend through the thickness of the veneer 3.2 length wood-

22、based panels long dimension of the test piece in the plane of the panel 3.3 specimen wood-based panels piece of the panel from which a test piece will be fabricated 3.4 test area wood-based panels that portion of the test piece from which the structural property is being evaluated 3.5 test piece woo

23、d-based panels specimen or aggregate of parts from a sample fabricated to the size and shape required for testing ISO 16572:2008(E) 2 ISO 2008 All rights reserved3.6 width wood-based panels short dimension of the test piece in the plane of the panel 4 Symbols and abbreviated terms A cross-sectional

24、area of the test piece within the gauge length, equal to bt, in square millimetres b measured width of test piece, in millimetres E modulus of elasticity, in megapascals F load, in newtons F maxmaximum load applied to the test piece, in newtons F increment of load on the linear portion of the load-d

25、eflection curve, in newtons (see Figure 1) f strength, in megapascals G modulus of rigidity, in megapascals I asecond moment of area, in millimetres to the fourth power k slope of the linear portion of the load versus deformation or deflection curve, in newtons per millimetre (see Figure 1) l length

26、 of test piece, in millimetres l 1gauge length, in millimetres l 2distance between an inner load point or line and the nearest support, in millimetres M moment, in newton millimetres t measured thickness of test piece, in millimetres t 1nominal thickness of the panel being tested, in millimetres u d

27、eflection or deformation, in millimetres u increment of deflection corresponding to F , in millimetres (see Figure 1) W section modulus, in millimetres to the third power Subscripts applied to loads, capacities, strengths, stiffnesses, and moduli of elasticity: app apparent c compression edge edgewi

28、se m bending s planar shear t tension true true bending v panel shear ISO 16572:2008(E) ISO 2008 All rights reserved 3Key X deflection or deformation Y load 1 slope = k NOTE Experience has demonstrated that suitable values of F 1and F 2are approximately 10 % and 40 % of F max , respectively. Figure

29、1 Load-deflection or deformation graph within the linear range 5 Sampling 5.1 Sampling of panels All panels in a sample shall be of the same type, grade, thickness range and composition and/or lay-up as defined in a standard or product specification. The sample shall be representative of the product

30、 as defined. 5.2 Sampling of specimens The position of the specimens within the panels shall be selected to ensure the sampling of specimens is unbiased. The specimens for each type of test in each direction shall be from a different position in different panels of the same sample. NOTE An example o

31、f a cutting schedule based on a sample of four panels, each with a minimum area of 1 200 mm 2 400 mm, is given in Annex B. ISO 16572:2008(E) 4 ISO 2008 All rights reserved6 Preparation of test pieces 6.1 Conditioning 6.1.1 Standard conditioning With the exception of 6.1.2, all test pieces shall be c

32、onditioned to constant mass in an atmosphere of relative humidity (65 5) % and temperature (20 2) C. Constant mass is deemed to be attained when the results of at least three successive weighings indicate the moisture content has stabilized to within 0,5 % for at least a 48 h period. If the conditio

33、ns of the testing room are not the same as those in the conditioning chamber, test pieces shall remain in the conditioning chamber until testing. 6.1.2 Alternative conditionings Test pieces may be differently conditioned and/or unconditioned. Unless otherwise noted in the test report, results from C

34、lauses 7 to 11 shall be corrected to reflect conditioning as specified in 6.1.1. The procedure for correcting structural properties shall be technically sound, using moisture content results from 6.3, and shall be recorded in the test report. 6.2 Dimensions of test pieces 6.2.1 Method of measurement

35、 The dimensions shall be determined in accordance with ISO 9424. 6.2.2 Measurements to be taken The thickness of the test pieces shall be measured at the four corners of the test area and averaged. With the exception of panel shear, methods A and B, the width of the test pieces shall be measured at

36、two points along each edge of the test area and averaged. The length of the test pieces for panel shear, method A, and planar shear, method A, tests shall be measured at two points along each edge of the test area and averaged. The length of the test pieces for panel shear, method B, shall be measur

37、ed along the centreline of the test area (including the radius section), as shown in Figure 9. If the thicknesses of individual plies or layers in plywood or composite panels are required, then each shall be measured to the nearest 0,1 mm at the four edges of the test piece and averaged. 6.3 Moistur

38、e content 6.3.1 Method of measurement The moisture content shall be determined in accordance with the procedures of ISO 16979. 6.3.2 Measurements to be taken The moisture content shall be determined from at least one test piece per panel and measured at the time of testing. 6.4 Density 6.4.1 Method

39、of measurement The density shall be determined in accordance with the procedures of ISO 9427. ISO 16572:2008(E) ISO 2008 All rights reserved 5 6.4.2 Measurements to be taken The density shall be determined from at least one test piece per panel and measured at the time of testing. 7 Bending properti

40、es 7.1 True bending properties flatwise 7.1.1 Test piece The test piece shall be rectangular in cross-section. The depth of the test piece shall be equal to the thickness of the panel, and the width shall be not less than 300 mm. The total length of the test piece shall be the span between the suppo

41、rts plus an overhang sufficiently long to prevent the test piece from slipping off the supports during testing. 7.1.2 Loading equipment The loading equipment shall be capable of measuring the load to an accuracy of 1 % of the maximum load. 7.1.3 Loading method The application of the load shall be as

42、 shown in Figure 2, with minimum dimensions as noted. Contact points for loads and reaction forces shall be continuous across the width of the test piece and (30 1) mm in diameter. The test hardware shall include appropriate mechanisms, such as rollers or pivots, to minimize the development of axial

43、 forces in the test piece and to allow the test piece to deflect freely under load. The application of the load shall create a zone of uniform bending moment between the load points, free of shear stresses. The recommended distance for l 2is 16t 1to preclude shear failures outside the zone of unifor

44、m bending moment. NOTE 1 Large deflections may occur when test pieces with small bending stiffness are tested to failure, thus alternative test arrangements may be required. In general, the test configuration described in this subclause is suitable for a test piece with a thickness greater than 9 mm

45、 (corresponding to a bending stiffness per unit width of about 300 kN mm 2 /mm). Smaller thicknesses may be tested by using smaller-diameter supports and proportionally reducing the distances between them. NOTE 2 Thick and/or wide test pieces may require larger-diameter supports. Dimensions in milli

46、metres Key 1 test piece Figure 2 True bending modulus of elasticity and stiffness test configuration ISO 16572:2008(E) 6 ISO 2008 All rights reserved7.1.4 Test procedure 7.1.4.1 Rate of application of load The load, F, shall be applied at a constant rate so that the maximum load is reached within (3

47、00 120) s. 7.1.4.2 Measurement of length and deformation The lengths l 1and l 2shall be measured to the nearest 1 mm. The deflection of the test piece shall be measured between two parallel lines, perpendicular to the span, located in the zone of uniform moment, as shown in Figure 2. This distance (

48、the gauge length) shall be not less than 250 mm. Deflection measurements may be referenced relative to the top or bottom of the test piece. Test pieces exhibiting excessive twist/warp may require two points of deflection measurement, in which case the average of the two readings shall be used in the

49、 calculations. The deflection over the gauge length shall be measured to the nearest 0,01 mm. For t 1less than 9 mm thick, the minimum 250 mm gauge length may be proportionally reduced, but should be as large as possible while maintaining adequate clearance between the gauges and the loading equipment. 7.1.5 Expression of results 7.1.5.1 True modulus of elasticity and bending stiffness The true bending modulus of elasticity of the test piece shall be calculated from the line