1、Designation: D 905 081Standard Test Method forStrength Properties of Adhesive Bonds in Shear byCompression Loading1This standard is issued under the fixed designation D 905; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1NOTEAdded research report footnote to Section
3、 13 editorially in May 2009.INTRODUCTIONThe accuracy of the results of strength tests of adhesive bonds will depend on the conditions underwhich the bonding process is carried out. Unless otherwise agreed upon by the manufacturer and thepurchaser, the bonding conditions shall be prescribed by the ma
4、nufacturer of the adhesive. In order toensure that complete information is available to the individual conducting the tests, the manufacturerof the adhesive shall furnish numerical values and other specific information for each of the followingvariables:(1) The moisture content of the wood at the ti
5、me of bonding.(2) Complete mixing directions for the adhesive.(3) Conditions for applications of the adhesive including the rate of spread or thickness of film,number of coats to be applied, whether to be applied to one or both surfaces, and the conditions ofdrying where more than one coat is requir
6、ed.(4) Assembly conditions before application of pressure, including the room temperature, length oftime, and whether open or closed assembly is to be used.(5) Curing conditions, including the amount of pressure to be applied, the length of time underpressure and the temperature of assembly when und
7、er pressure. It should be stated whether thistemperature is that of the bond line, or of the atmosphere at which the assembly is to be maintained.(6) Conditioning procedure before testing, unless a standard procedure is specified, including thelength of time, temperature, and relative humidity.Arang
8、e may be prescribed for any variable by the manufacturer of the adhesive if it can be assumedby the test operator that any arbitrarily chosen value within such a range or any combination of suchvalues for several variables will be acceptable to both the manufacturer and the purchaser of theadhesive.
9、1. Scope1.1 This test method covers the determination of the com-parative shear strengths of adhesive bonds used for bondingwood and other similar materials, when tested on a standardspecimen under specified conditions of preparation, condition-ing, and loading in compression. This test method is in
10、tendedprimarily as an evaluation of adhesives for wood.1.2 The values stated in SI units are to be regarded as thestandard. The values given in brackets are provided forinformation purposes only.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use.
11、 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 143 Test Methods for Small Clear Specimens of TimberD 907 Terminology of Ad
12、hesives1This test method is under the jurisdiction of ASTM Committee D14 onAdhesives and is the direct responsibility of Subcommittee D14.30 on WoodAdhesives.Current edition approved Oct. 1, 2008. Published October 2008. Originallyapproved in 1947. Last previous edition approved in 2003 as D 905 03.
13、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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box
14、C700, West Conshohocken, PA 19428-2959, United States.D 5266 Practice for Estimating the Percentage of WoodFailure in Adhesive Bonded Joints3. Terminology3.1 DefinitionsMany terms in this test method are definedin Terminology D 907.4. Significance and Use4.1 It cannot be assumed that this test metho
15、d measures thetrue shear strength of the adhesive bond. Many factors interfereor bias the measurement including the strength of the wood, thespecimen, the shear tool designs themselves, and the rate ofloading.4.1.1 Wood failure is very common in joints made withstrong adhesives. Although high wood f
16、ailure is normallydesired, when it occurs the measured strength is lower than thetrue adhesive bond strength.4.1.2 Stress concentrations at the notches of the specimentend to lower the measured strength. In a similar test for theshear strength of solid wood, Test Methods D 143, these effectsare self
17、 correcting so that the measured strength is close to thetrue shear strength of the wood. By analogy the same may betrue in this test method, however, other factors are alsoinvolved and may alter the relationship.4.1.3 The rate of loading affects the strength of an adhesivebond according to the adhe
18、sives rheological properties. Themore viscoelastic or plastic the adhesive, the greater effect.Thermosetting adhesives like urea- and phenol-formaldehydeare elastic. Their bond strengths can be measured over a rangeof loading rate from 0.038 to 1.27 cm/min 0.015 to 0.5in./min with no apparent affect
19、. Thermoplastic adhesives likepolyvinyl acetate, hot melts, and elastomer-based adhesivesexhibit a broad range of elastic, viscoelastic, and plasticbehaviors. Their bond strengths will be affected to varyingdegrees by changing the loading rate. Generally, increasing therate, increases the measured s
20、trength.4.2 This test method is suitable for product research anddevelopment, qualifying adhesives in accordance with certainproduct or performance specifications, and monitoring bondingprocess control. This test method may be suitable for compar-ing and selecting adhesives, however, such comparison
21、s mustbe made with caution since the measured strength of someadhesives may be different in different types of joints. Strengthvalues obtained by this test method are not suitable as designshear strengths values without adjustment by certain engineer-ing design factors.5. Apparatus5.1 The testing ma
22、chine shall have a capacity of not lessthan 6810 kg 15 000 lb in compression and shall be fittedwith a shearing tool containing a self-aligning seat to ensureuniform lateral distribution of the load. The machine shall becapable of maintaining a uniform rate of loading such that theload may be applie
23、d with a continuous motion of the movablehead to maximum load at a rate of 5 mm 0.20 in./min with apermissible variation of 625 %. The shearing tool shown inFig. 1 has been found satisfactory. The testing machine shall belocated in an atmosphere such that the moisture content of thespecimens develop
24、ed under the conditions prescribed in Sec-tion 8 is not noticeably altered during testing.6. Test Specimens6.1 Test specimens shall conform to the form and dimen-sions shown in Fig. 2. The specimens shall be cut from testjoints prepared as described in Sections 7 and 8.6.2 At least 20 specimens shal
25、l be tested, representing atleast four different joints.7. Preparation of Test Joints7.1 Hard maple blocks (Acer saccharum or Acer nigrum),having a minimum specific gravity of 0.65 based on oven-dryweight and volume shall be selected (see Note 1). These blocksshall be of straight grain and free from
26、 defects including knots,birdseye, short grain, decay, and any unusual discolorationswithin the shearing area. The blocks shall be of suitable sizepreferably so that five test specimens may be cut from one testjoint as shown in Fig. 3. Blocks approximately 19 by 63.5 by304 mm 34 by 212 by 12 in. hav
27、e been found to beFIG. 1 Shearing ToolD9050812satisfactory for this purpose. The grain direction shall beparallel to the longest dimension of the block. The blocks shallbe at the equilibrium moisture content recommended by themanufacturer of the adhesive. In the absence of such recom-mendation, the
28、moisture content shall be from 10 to 12 %based on oven-dry weight as determined on representativesamples in accordance with the “Moisture Determination”section of Test Methods D 143. The blocks shall be surfaced,just prior to bonding, preferably with a hand-feed jointer, andthe blocks weighed and as
29、sembled in pairs so that blocks ofapproximately the same specific gravity are bonded together.The surfaces shall remain unsanded and shall be free from dirt.NOTE 1A method for selecting maple blocks of satisfactory specificgravity is described in the Appendix to this method. For referee tests, thesp
30、ecific gravity of blocks may be determined in accordance with theprocedure described in the “Specific Gravity and Shrinkage in Volume”section of Test Methods D 143.7.2 The adhesive shall be prepared and applied to the blocksin accordance with the procedure recommended by the manu-facturer of the adh
31、esive. The adhesive-coated blocks shall thenbe assembled and pressed, likewise in accordance with therecommendations of the manufacturer of the adhesive.8. Conditioning of Test Joints8.1 The joints, upon removal from pressure shall be condi-tioned at a relative humidity of 50 6 2 % and at a temperat
32、ureof 23 6 1C 73.4 6 2F either for a period of 7 days or untilspecimens reach equilibrium as indicated by no progressivechanges in weight, whichever is the shorter period. The lengthof this period of conditioning may be extended beyond thislimit by written agreement between the purchaser and themanu
33、facturer of the adhesive.9. Preparation of Specimens9.1 Cut the specimens as shown in Fig. 3 so that the graindirection is parallel to the direction of loading during test. Takecare in preparing the test specimens to make the loadedsurfaces smooth and parallel to each other and perpendicular tothe h
34、eight. Take care also in reducing the lengths of thelaminations to 44.4 mm 134 in. to ensure that the saw cutsextend to, but not beyond, the bond line. Measure the widthand length of the specimen at the bond line to the nearest 0.25mm 0.010 in. to determine the shear area.9.2 Retain specimens in the
35、 conditioning atmosphere de-scribed in Section 8 until tested, except during the cuttingoperations.10. Procedure10.1 Place the test specimen in the shearing tool so that theload may be applied as described in Section 5. The position ofthe specimen in one type of shearing tool is shown in Fig. 1.Appl
36、y the loading with a continuous motion of the movablehead at a rate of 5 mm 0.20 in./min to failure as prescribed inSection 5.11. Calculation11.1 Calculate the shear stress at failure in kilopascals(pounds-force per square inch) based on the bond line areabetween the two laminations measured to the
37、nearest 0.06cm20.01 in.2, and report for each specimen together with theestimated percentage of wood failure. Practice D 5266 hasbeen found useful in estimating the percentage of wood failurein adhesive bonded joints.12. Report12.1 The report shall include the following:12.1.1 Complete identificatio
38、n of the adhesive tested, in-cluding type, source, manufacturers code numbers, form, etc.12.1.2 Application and bonding conditions used in prepar-ing the specimens.12.1.3 Conditioning procedure used for the specimens.12.1.4 Temperature and relative humidity in the test room.12.1.5 Number of specimen
39、s tested.12.1.6 Number of joints represented.12.1.7 Maximum and minimum shear stresses at failure andpercentages of wood failure. The standard deviation or allindividual test values, or both, for the failing load values andwood failure values may be included in the report at the optionof either the
40、purchaser or the manufacturer of the adhesive.12.1.8 The average shear stress at failure and the averagepercentage of wood failure.13. Precision and Bias313.1 Precision:3Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: D141015.Me
41、tric Equivalentsin.mm146.3341913444.4250.8FIG. 2 Form and Dimensions of Test SpecimenMetric Equivalentsin.mm146.3341913444.4250.8FIG. 3 Test Joint Showing Method of Cutting Five TestSpecimensD905081313.1.1 Precision has two components: repeatability at agiven test site and reproducibility between te
42、st sites. Theprecision of this test method is affected by many factorsincluding, but not limited to: (11) the wood species, (2) theboards selected, (3) grain direction, (4) growth ring orientation,(5) the quality of the bonded joint, (6) the condition of theshear tool, (7) the precision on the testi
43、ng machine, and (8) theoperator. When the specimen fails primarily in the wood, thenormally variability of the wood strength affects the precision.The coefficient of variation of shear strength parallel to thegrain is 14 % for a given species of wood.13.1.2 Repeatability at a Given Site:13.1.2.1 In
44、a study in which all the above factors wereclosely controlled and the specimens were bonded with phenol-resorcinol formaldehyde adhesive, the coefficient of variationranged from 2.4 up to 13.0 %, with most values in the range of3to6%.13.1.2.2 In a study in which all the above factors, exceptboard an
45、d growth ring orientation, were controlled, the coef-ficients of variation ranged from 8 to 11 % for casein bondedspecimens, 4 to 12 % for two polyvinyl acetates, 22 to 27 % foran elastomer-based, and 14 to 21 % for phenol-resorcinolformaldehyde adhesive bonded specimens.13.1.3 Reproducibility from
46、site to site:13.1.3.1 The reproducibility of this test method has not beenestablished.13.2 BiasBias is the difference between the true shearstrength of the adhesive bond and the strength measured by amethod that is repeatable. Bias arises from the design, method,rate of loading the specimen, and fro
47、m the strength of thewood.14. Keywords14.1 adhesive; bond; compression; compression loading;shear; strength propertiesAPPENDIX(Nonmandatory Information)X1. METHOD FOR SELECTING MAPLE BLOCKS OF SATISFACTORY SPECIFIC GRAVITYX1.1 Cut the hard maple blocks into some standard sizesuch as 19 by 63.5 by 30
48、4 mm 34 by 212 by 12 in. afterconditioning. Measure the linear dimensions of the blocks ininches, using a suitable caliper or other measuring device.Determine the percentage moisture content of the blocks inaccordance with the “Moisture Determination” section of TestMethods D 143. Do not use these s
49、amples in further tests.X1.2 Calculate the volume of the blocks to the nearest 1cm30.1 in.3 and express the average percentage moisturecontent to the nearest whole number. Determine the numericalvalue of the factor for this moisture content by reference toTable X1.1, which is based on hard maple blocks that have aspecific gravity of 0.65 on the oven-dry weight and volumebasis and which were conditioned to various moisture contentvalues.X1.3 Multiply the factor in Table X1.1 by the volume of theblock in cubic inches to obtain the weight o
