1、Designation:D468098(Reapproved 2011)Standard Test Method forCreep and Time to Failure of Adhesives in Static Shear byCompression Loading(Wood-to-Wood)1This standard is issued under the fixed designation D4680;the number immediately following the designation indicates the year oforiginal adoption or,
2、in the case of revision,the year 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.1.Scope1.1 This test method covers the determination of time-dependent properties of structural ad
3、hesives in wood-to-woodbonds when specimens are subjected to shearing stresses atvarious levels of static load,constant temperature,and relativehumidity.Apparatus and procedures are provided for directmeasurement of time-dependent shear deformation(creep)andtime to failure of adhesive bonds under st
4、atic load.Guidelinesfor selecting test conditions,methods for calculating creep rate,creep strain,creep modulus,and extrapolation of time tofailure,are given along with methods of presenting these data.1.2 The values stated in inch-pound units are to be regardedas standard.The values given in parent
5、heses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate sa
6、fety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D143 Test Methods for Small Clear Specimens of TimberD905 Test Method for Strength Properties of AdhesiveBonds in Shear by Compression LoadingD907 Terminology o
7、f AdhesivesD2016 Methods of Test for Moisture Content of Wood(Withdrawn 1987)32.2 ASTM Adjuncts:Compression-Shear Creep Test Apparatus43.Terminology3.1 Definitions:3.1.1 Many terms in these test methods are defined inTerminology D907.3.1.2 creep,nthe dimensional change with time of amaterial under l
8、oad,following the initial instantaneous elasticor rapid deformation.Creep at room temperature is sometimescalled cold flow.3.1.3 creep modulus,nthe ratio of initial applied stress tocreep strain.3.1.4 creep strain,nthe total strain,at any given time,produced by the applied stress during a creep test
9、.3.1.4.1 DiscussionIn this test method,creep strain iscalculated by dividing displacement at any given time by theestimated apparent thickness of the adhesive bondline.3.1.5 rate of creep,nthe slope of the creep-time curve ata given time.3.1.6 shear stress,nthe stress component tangential to theplan
10、e on which the forces act,that is,in the plane of the bondline.3.1.7 strain,nthe unit change,due to stress,in the size orshape of a body referred to its original size or shape.3.1.8 stress,nthe force exerted per unit area at a pointwithin the plane.4.Significance and Use4.1 Creep data that are obtai
11、ned over a relatively shortperiod of time in this test method can provide a measure of anadhesive bonds ability to withstand static loading in shear overa relatively long period of time.Creep measurements are madeover a range of expected service conditions,including level ofstress,temperature,relati
12、ve humidity,and duration of load.Creep rate,creep strain,and creep modulus are calculated atthe various service conditions.1This 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 A
13、pril 1,2011.Published April 2011.Originallyapproved in 1987.Last previous edition approved in 2004 as D4680 98(2004).DOI:10.1520/D4680-98R11.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume i
14、nformation,refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from ASTM International Headquarters.Order Adjunct No.ADJD4680.Original adjunct produced in 1987.Copyright ASTM International,100
15、Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.2 Creep data can be used to(1)predict performance of anadhesive under long-term loading,(2)characterize an adhesive,(3)compareadhesiveswitheachotherandagainstspecifications,and(4)design structural members fabricatedwith a
16、n adhesive.4.3 Time-to-failure data provide a measure of the ultimateload-carrying ability of an adhesive bond as a function of timeat various levels of stress,temperature,and relative humidity.4.4 With proper caution,time-to-failure data derived fromrelatively short loading periods can be extrapolated to estimatethe useful service life of an adhesive at working levels of staticstress.This property may also be used with creep data toaccomplish purposes listed in 4.2.4.5 This test method is a res
