1、Designation: D 5266 99 (Reapproved 2005)Standard Practice forEstimating the Percentage of Wood Failure in AdhesiveBonded Joints1This standard is issued under the fixed designation D 5266; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revis
2、ion, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice provides procedures for estimating thepercentage of wood failure that occurs in plywoo
3、d-shear,block-shear, finger joint test specimens, or any other bondlineinvolving wood.1.2 The values stated in SI units are to be regarded as thestandard. The values in parentheses are provided for informa-tion only.1.3 This standard does not purport to address all of thesafety concerns, if any, ass
4、ociated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 905 Test Method for Strength Properties of AdhesiveBon
5、ds in Shear by Compression LoadingD 906 Test Method for Strength Properties of Adhesives inPlywood Type Construction in Shear by Tension LoadingD 2559 Specification for Adhesives for Structural Lami-nated Wood Products for Use Under Exterior (Wet Use)Exposure ConditionsD 4688 Test Method for Evaluat
6、ing Structural Adhesivesfor Finger Jointing LumberD 5572 Specification for Adhesives Used for Finger Jointsin Nonstructural Lumber ProductsD 5751 Specification for Adhesives Used for LaminateJoints in Nonstructural Lumber Products2.2 American National Standards:ANSI/HPMA HP American National Standar
7、d for Hard-wood and Decorative Plywood3ANSI/AITC A190.1 American National Standard for WoodProductsStructural Glued, Laminated Timber42.3 Other Standards:American Plywood Association Proposed Standard Methodfor Estimating Percentage Wood Failure on PlywoodShear Specimens5PS 1 U.S. Product Standard f
8、or Construction and IndustrialPlywood5Wood Handbook: Wood as an Engineering Material, Agri-cultural Handbook No. 72, Forest Service, Forest Prod-ucts Laboratory (1987)6Inspection Bureau Memorandum No. 1 Interpretation ofWood Failure42.4 ASTM Adjunct:Photographs for Visually Estimating the Percentage
9、 of WoodFailure in Standard Adhesively Bonded Specimens73. Terminology3.1 Definitions:3.1.1 deep wood failure, nfailure that is invariably severalto many cells away from the adhesive layer, in which thefracture path is strongly influenced by the grain angle andgrowthring structure.3.1.2 shallow wood
10、 failure, nfailure that is invariablywithin the first one or two layers of cells beyond the adhesivelayer in which the fracture path is not influenced by thewoodgrain angle or growth-ring structure (see 7.7 and 8.1).3.1.3 wood failure, nthe rupturing of wood fibers instrength tests on bonded specime
11、ns, usually expressed as thepercentage of the total area involved which shows such failure.4. Significance and Use4.1 Wood failure is one of the principal means for deter-mining the quality of an adhesively bonded wood joint.4.2 When evaluated after a water soaking, water soakingand drying, or boili
12、ng and drying, the percentage of wood1This practice is under the jurisdiction of ASTM Committee D14 on Adhesives,and is the direct responsibility of Subcommittee D14.30 on Wood Adhesives.Current edition approved April 1, 2005. Published May 2005. Originallyapproved in 1992. Last previous edition app
13、roved in 1999 as D 5266 99.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Hardwood Plywood M
14、anufacturers Association, 1825 MichaelFaraday Drive, P.O. Box 2789, Reston, VA 22090-2789.4Available from American Institute for Timber Construction, 11818 S. E. MillPlain Blvd., Suite 415, Vancouver, WA 98684-5092.5Available from American Plywood Association, P.O. Box 11700, Tacoma, WA98411-0700.6A
15、vailable from U.S. Government Printing Office Superintendent of Documents,732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401.7Available from ASTM International Headquarters. Request Adjunct No.ADJD5266.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA
16、 19428-2959, United States.failure is an important criterion for qualifying adhesives for usein plywood and glued laminated structural timber for exterioruse, and for daily quality control of the processes for manu-facturing plywood and glued, laminated timbers. Standards thatuse the percentage of w
17、ood failure are included in Section 2.4.3 In plywood manufactured from North American soft-wood species, the percentage of wood failure of Test MethodD 906 specimens, tested wet after either a vacuum-pressuresoak-dry or boil-dry treatment, correlates with the percentageof panels that delaminate in o
18、utdoor exposure without protec-tion.84.4 Similar correlations for other products have not beenpublished.5. Apparatus5.1 Various light sources have been found useful in estimat-ing wood failure. In determining compliance to standardspecifications, the source must be agreed upon by the user ofthis pra
19、ctice and the individual or agency requiring these tests.5.1.1 Dual-Element Fluorescent Desk Lamp equipped withone 15 W daylight and one 15 W cool white tube.NOTE 1This source is used by the American Plywood Association forcompliance to the commercial standard PS 1.5.1.2 Circular Fluorescent Desk La
20、mp with 53 viewingmagnifier in the center of the lamp.5.1.3 Diffuse Natural Light from a window facing awayfrom the sun.5.2 Ruler, with 2.54 mm (0.1-in.) divisions is recommendedas an aid to estimating the area of torn wood fibers. Atransparent template, the size of the specimen bond area andscribed
21、 with various shapes and areas with known percentagesof the total area, is also useful for subdividing the area. Anexample of such a template is shown in Fig. 1.5.3 Low-Power Magnifying Glass,of3to53, with a fieldof view able to encompass most of the failed surface, may beuseful for inspecting areas
22、 where shallow wood failure issuspected.6. Preparation of Test Specimens6.1 Prepare and test the specimens as outlined in theappropriate test method.6.2 Do not estimate wood failure percentage of specimenswith localized defects such as knots, knotholes, burl, and voidsin the bond area, even if they
23、are permitted within the grade oflumber or veneer being tested. Specimens with defects in thegrip area may or may not be tested at the discretion of the useror in accordance with the policy of the testing organization.6.3 Specimens with manufacturing defects, such as wipedbondline, chips, core gaps,
24、 and laps, may also be discarded byagreement between the interested parties.6.4 If the specimens were tested wet, dry the failed surfacesin an air-circulating oven at 71C (160F), or under equivalentconditions, before estimating the percentage of wood failure.7. Procedure7.1 Work in a location where
25、direct outside light does notfall on the specimen.7.2 Select a light source described in 5.1, and use itconsistently.7.3 Open specimen halves as you would open a book.7.4 Position the specimen below the light source as follows:7.4.1 PlywoodHold plywood specimens with the longdimension perpendicular
26、to the line between the light sourceand the eye.7.4.2 Parallel LaminatesHold specimens with the graindirection perpendicular to the line between the light source andthe eye. Tilt the specimen to reflect light from the light sourceto the eye.7.4.3 Finger jointsHold the specimen with the length ofthe
27、fingers perpendicular to the line between the light sourceand the eye.7.4.4 Refer to Fig. 2 for general positioning of the lightsource and the specimen grain direction in relation to the eye.In general, with the exception of plywood specimens, the graindirection is perpendicular to the line of sight
28、 between the lightsource and the eye.7.5 Vary the tilt of the specimen, as shown in the side viewin Fig. 2, so that areas of wood and adhesive failure can be8Perkins, N. S., Predicting Exterior Plywood Performance, Proceedings ForestProducts Research Society, 1950, pp. 112.NOTE 1In this case, a stan
29、dard D 905 shear block is shown.FIG. 1 Example of Plastic Template Scribed with Lines andShapes Representing Known Percentages of Given AreaD 5266 99 (2005)2distinguished. Exercise care not to create shadows, especiallyin the case of deep wood failure.7.6 When there is little color contrast between
30、the wood andthe adhesive, and the wood failure is shallow, special measuresmay be required.7.6.1 Dyes are sometimes helpful in distinguishing woodfailure from light-colored adhesive. For example, aqueousiodine solution turns polyvinyl acetate adhesive black. Anaqueous solution of fast green stain co
31、lors unpenetrated woodfibers green, but does not color urea-formaldehyde adhesive oradhesive-penetrated wood.7.6.2 Magnification, rotation of the specimen, and variationof the incident angle of the light on the surface are oftennecessary to distinguish shallow wood failure from adhesivefailure, espe
32、cially when the adhesive is light colored ortransparent. Magnification may or may not be used to make theactual estimate of wood failure; however, the practice shouldbe consistent. If the specimen is rotated to detect shallow woodfailure, always reposition the specimen in the standard positionwhen m
33、aking the estimate of wood failure.7.7 If there are scattered areas of shallow wood failure, blowor brush loose fibers from the surface. Count as wood failureonly areas with wood cells that actually adhere to the adhesive.Mentally group those areas into an area that can be estimated.7.8 Do not count
34、 as wood failure isolated wood particlessuch as sawdust and slivers that were on the surface during thebonding process, unless these particles were actually torn apartduring testing.7.9 It is often helpful to use a ruler or a scribed transparenttemplate as described in 5.2 as an aid to estimate the
35、totalpercentage of wood failure, or the percentages of shallow anddeep wood failure.7.10 Mentally divide the surface into quadrants for estimat-ing the areas of various forms of failure. Estimate the woodfailure on both halves of the specimen, but do not count thewood failure from matching areas mor
36、e than once. Alterna-tively, read the wood failure percentage on both halves of thespecimen and divide the sum by 2.7.11 Estimate shallow and deep or total wood fiber failure ofeach specimen to the nearest 5 %, with a maximum of 100 %of the total bonded test area.NOTE 2The North American plywood ind
37、ustry recognizes shallowwood failure, but does not give it any less or any more significance thandeep wood failure. Therefore in the case of conformance to PS 1, shallowand deep wood failure are not distinguished and should be estimatedtogether.8. Evaluation of Wood Failure8.1 Accurate and consisten
38、t estimates are important. Gen-erally, wood failure estimators do not have difficulty with veryhigh or low percentages of wood failure. Difficulty occurs inthe middle pass-fail range (30 to 85 %, depending on thestandard) where accuracy is most important. Special care mustbe taken in this range.8.2
39、The color of the adhesive and recognition of shallowwood failure, if present, affect the estimate. Shallow woodfailure is more easily recognized and distinguished with a darkadhesive as a background. When the adhesive is light colored,shallow wood failure can be easily mistaken for adhesive oradhesi
40、on failure.8.3 If the percentage of wood failure is high and the failureis mostly on one side of the adhesive layer, the grain orienta-tion may be a factor. In this case, the grain orientation shouldbe determined and recorded.8.4 Record any indications of poor spread, lack of adhesivetransfer, or ot
41、her bonding problems.9. Report9.1 Report for each specimen as follows:9.1.1 The exposure or treatment of the specimen beforetesting.9.1.2 The percentage of total wood failure.9.1.3 If there is shallow wood failure, report separatepercentages for shallow and deep wood failure.NOTE 3See Note 2 regardi
42、ng practice in the plywood industry.9.1.4 Grain deviations, if affecting the percentage of woodfailure.9.1.5 Indications of improper bonding conditions affectingthe percentage of wood failure.9.2 For all specimens, report the following:9.2.1 The average of each wood failure category; total,shallow,
43、deep.9.2.2 The standard deviation of each category of woodfailure percentage.10. Keywords10.1 adhesive; finger joints; parallel laminates; plywood;wood failureFIG. 2 Positioning of Test Specimen in Relation to Light Sourceand EyeD 5266 99 (2005)3ASTM International takes no position respecting the va
44、lidity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is su
45、bject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headqu
46、arters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This stand
47、ard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D 5266 99 (2005)4
