DIN EN 14272-2012 Plywood - Calculation method for some mechanical properties German version EN 14272 2011《胶合板 某些机械性能的计算方法》.pdf

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1、Translation by DIN-Sprachendienst.English price group 18No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 79.060.10!$

2、z*“1870758www.din.deDDIN EN 14272Plywood Calculation method for some mechanical propertiesEnglish translation of DIN EN 14272:2012-03Sperrholz Rechenverfahren fr einige mechanische EigenschaftenEnglische bersetzung von DIN EN 14272:2012-03Contreplaqu Mthode de calcul pour certaines caractristiques m

3、caniquesTraduction anglaise de DIN EN 14272:2012-03SupersedesDIN V ENV 14272:2002-12www.beuth.deIn case of doubt, the German-language original shall be considered authoritative.Document comprises 49 pages02.12March 2012DIN EN 14272:2012-03 2 A comma is used as the decimal marker. National foreword T

4、his standard has been prepared by Technical Committee CEN/TC 112 “Wood-based panels” (Secretariat: DIN, Germany). The responsible German body involved in its preparation was the Normenausschuss Holzwirtschaft und Mbel (Timber and Furniture Standards Committee), Working Committee NA 042-02-15 AA Holz

5、werkstoffe Spiegelausschuss zu CEN/TC 112 und ISO/TC 89. Amendments This standard differs from DIN V ENV 14272:2002-12 as follows: a) calculation applies to panels of any composition, symmetrical or not; b) values resulting for the panels can be used for calculation as characteristic values as requi

6、red by EN 1995-1-1; c) a new Annex A (normative) provides the derivation for the veneer values (basic values); d) a new Annex B (normative) provides practical spreadsheets to derive the properties; e) a new Annex C gives an example of bending strength. Previous editions DIN V ENV 14272: 2002-12 EURO

7、PEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 14272 December 2011 ICS 79.060.10 Supersedes ENV 14272:2002English Version Plywood - Calculation method for some mechanical properties Contreplaqu - Mthode de calcul pour certaines caractristiques mcaniques Sperrholz - Rechenverfahren fr einige mechan

8、ische Eigenschaften This European Standard was approved by CEN on 1 October 2011. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and

9、bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the re

10、sponsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany,

11、 Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. Management Centre: Avenue Marnix 17, B-1000 Brussels 2011 CEN All rights of exploitation in any form and

12、 by any means reserved worldwide for CEN national Members. Ref. No. EN 14272:2011: EEUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG EN 14272:2011 (E) 2 Contents Page Foreword 41 Scope 52 Normative references 53 Principle 54 Terms and definitions .

13、65 Symbols 65.1 Main symbols .65.2 Subscripts 76 Calculation method86.1 General 86.2 Properties relevant to the calculation methods .86.3 Wood species .86.4 Factors for plywood composition 87 Characteristic values for strength and stiffness in bending, tension and compression 117.1 General . 117.2 B

14、ending 117.2.1 General . 117.2.2 Modulus of elasticity 117.2.3 Strength . 117.3 Tension and compression . 127.3.1 Stiffness and capacity of the layers in the cross section 127.3.2 Stiffness and capacity of the panel. 137.3.3 Property of the panel (as if homogenized) . 137.4 Property values for layer

15、s 137.4.1 General . 137.4.2 Modulus of elasticity (, ; . 147.4.3 Resistance . 148 Shear properties . 158.1 Panel shear 158.1.1 Panel shear rigidity (Gv) . 158.1.2 Panel shear strength (fv) 168.2 Planar shear 168.2.1 General . 168.2.2 Planar shear rigidity (Gr) 168.2.3 Planar shear strength (fr) . 17

16、9 Ratio of strength upon modulus . 1710 Density . 1711 Conversion from strength and modulus of elasticity to capacity and stiffness 18Annex A (normative) Derivation for the veneer values (or basic values) . 19A.1 Scope . 19A.2 Principle . 19A.2.1 Option 1: Using plywood test results . 19A.2.2 Option

17、 2: Using solid timber properties . 19A.3 Procedure for derivation of properties from testing plywood . 19A.3.1 General . 19A.3.2 Sampling 20DIN EN 14272:2012-03EN 14272:2011 (E) 3 A.3.3 Test pieces . 20A.3.4 Testing 20A.3.5 Exploitation of the results 21A.4 Derivation of estimated values for veneer

18、s 25A.4.1 General . 25A.4.2 Values obtained by testing . 25A.4.3 Imposed values 25A.5 Report . 25Annex B (normative) Practical spreadsheets to derive the properties 27B.1 General . 27B.2 Bending 28B.2.1 General . 28B.2.2 Main tables . 28B.2.3 Tables for strength values 31B.3 Tension and compression

19、33B.4 Panel shear 39B.5 Planar shear . 40B.5.1 General . 40B.5.2 Available veneer values 40B.5.3 Veneer values not available . 42Annex C (informative) Example of bending strength 43C.1 Determination of the stress in the layers 43C.2 Determination of the panel strength 45Bibliography 47DIN EN 14272:2

20、012-03EN 14272:2011 (E) 4 Foreword This document (EN 14272:2011) has been prepared by Technical Committee CEN/TC 112 “Wood-based panels”, the secretariat of which is held by DIN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by

21、 endorsement, at the latest by June 2012, and conflicting national standards shall be withdrawn at the latest by June 2012. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for ident

22、ifying any or all such patent rights. This document supersedes ENV 14272:2002. Annex A and Annex B are normative. Compared to ENV 14272:2002, the following modifications have been made: a) calculation applies to panels of any composition, symmetrical or not; b) values resulting for the panels can be

23、 used for calculation as characteristics values as required by EN 1995-1-1; c) new Annex A (normative) provides the derivation for the veneer values (basic values); d) new Annex B (normative) provides practical spreadsheets to derive the properties; e) new Annex C (informative) gives an example of b

24、ending strength. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary,

25、 Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. DIN EN 14272:2012-03EN 14272:2011 (E) 5 1 Scope This European Standard specifies, for plywood panels of any compositi

26、on, symmetrical or not, a calculation method to derive some mechanical properties (strength and stiffness in bending, tension, compression, panel and planar shear) as well as density from the wood compounding the layers. NOTE Usually, the lay-up of the panels is symmetrical but, very often, the surf

27、ace appearance of the face and the surface appearance of the back face differ, hence a difference between the mechanical properties of the respective veneers. Therefore, in this case, the composition is not mechanically symmetrical and a symmetry independent calculation method is needed. Provided th

28、at structural characteristic values are taken for the layers, the resulting values for the panels can be used as characteristic values as required by EN 1995-1-1. Conversely, Annex A defines the procedures to derive the veneer properties, in bending, tension and compression, either from testing pane

29、ls according to EN 789 and EN 1058 or from timber testing according to EN 408 or from imposed values defined in EN 338. Annex B provides practical spreadsheets, which are applications of the equations in the main part of this standard. Annex C provide an example for the calculation of bending streng

30、th, in accordance with Annex B. 2 Normative references The following referenced documents are indispensable for 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) app

31、lies. EN 325, Wood-based panels Determination of dimensions of test pieces EN 338:2009, Structural timber Strength classes EN 384, Structural timber Determination of characteristic values of mechanical properties and density EN 408, Timber structures Structural timber and glued laminated timber Dete

32、rmination of some physical and mechanical properties EN 789, Timber structures Test methods Determination of mechanical properties of wood based panels EN 1058, Wood-based panels Determination of characteristic 5-percentile values and characteristic mean values EN 12369-2, Wood-based panels Characte

33、ristic values for structural design Part 2 Plywood EN 14358, Timber structures Calculation of characteristic 5-percentile values and acceptance criteria for a sample 3 Principle Using the mechanical properties of the wood species, which compound the layers (in this standard referred to as veneer or

34、basic values), it consists in deriving, by calculation, the mechanical properties of a panel. For bending, tension and compression, each layer property value, along and across the length of the panel, is weighted by a geometrical factor related to its weight in the panel cross section. DIN EN 14272:

35、2012-03EN 14272:2011 (E) 6 In this standard, where a value for a given property of the veneers is derived with a specified test method (including exploitation of the results), the models in this standard will provide a panel value for that property as if derived with the specified test method. EXAMP

36、LE For instance, if, in a panel composition, a specified percentile of a bending property of veneers is determined with EN 789 and EN 1058, the calculated value of the bending property of the panel will be its specified percentile as if determined by using EN 789 and EN 1058. 4 Terms and definitions

37、 For the purposes of this document, the following terms and definitions apply. 4.1 characteristic strength population fifth percentile value relating to a temperature of 20 C and a relative humidity of 65 % 4.2 characteristic stiffness either the population fifth percentile or the mean value relatin

38、g to a temperature of 20 C and a relative humidity of 65 % 4.3 characteristic density population fifth percentile value with mass and volume corresponding to equilibrium at a temperature of 20 C and a relative humidity of 65 % either of the wood species or of the panels, single species or mixed spec

39、ies NOTE The density values found from calculation refer to the minimum acceptable density of veneers used in the lay-up of plywood. In the case of single species plywood these values are taken as the characteristic values for the plywood. In the case of mixed species plywood the characteristic valu

40、e of density of the panel is calculated from the characteristic densities of the individual veneers according to the proportion of each species 4.4 veneer value or basic value characteristic value of a property to be used for each layer in the equations of the calculation method NOTE Characteristic

41、values of the wood species, along and across the grain, are fifth percentile values for strength but either mean values or fifth percentile values for stiffness (modulus of elasticity). 4.5 reference panel value value of a given mechanical property of a panel composition NOTE It is to be used to der

42、ive the veneer value (or basic value) of the property. 5 Symbols 5.1 Main symbols A area (b tnom), in square millimetres f strength, in Newtons per square millimetre E modulus of elasticity, in Newton per square millimetre Fs shear forces in a bending panel, in Newtons DIN EN 14272:2012-03EN 14272:2

43、011 (E) 7 G modulus of rigidity, in Newtons per square millimetre b width of panel (equal to 1 in the equations), in millimetres t, thickness of layers, in millimetres T thickness of panels, in millimetres W section modulus, equal to ( )6/.2nomtb , in cubic millimetres I second moment of area, equal

44、 to ()12/.3nomtb , in millimetres to the fourth power density, in kilograms per cubic metre kamodification factor, appearance class grade z distance of the axis of a layer to the neutral axis of the panel, in millimetres distance of the neutral axis from either face of the panel, in millimetres Ecc

45、eccentricity factor, no dimension L/L relative elongation of the layers (bending, tension and compression) P property V strength or modulus, in Newton per square millimetre Rw in the set of layers, the weaker ratio of strength upon modulus for the properties of the wood species involved in the compo

46、sition of a panel Up stiffness of the panel s standard deviation 5.2 Subscripts m bending t tension c compression v panel shear r planar shear w applies to the lower ratio strength/modulus (f/E) of a property of a layer in a multi-species panel nom, mean nominal value and mean value respectively n n

47、umber of layers of the panel (from top face to bottom face) i rank of layers from top face ax stands for neutral axis in bending density 0 parallel to length of the plywood (direction of the grain of the face layers) 90 perpendicular to the length DIN EN 14272:2012-03EN 14272:2011 (E) 8 05 5 percent

48、ile characteristic value 6 Calculation method 6.1 General The mechanical properties of plywood, in bending, tension, compression panel shear and planar shear can be derived by calculation. The calculation method described in this standard can be applied to plywood panels of any composition, symmetri

49、cal or not. For the classification according to appearance classes of plywood, see EN 635-2 and EN 635-3. 6.2 Properties relevant to the calculation methods For calculation of characteristic values of mechanical properties for different plywood compositions, the values of the properties of the veneers compounding the layers shall be derived in accordance with Annex A. Th