杨木横纹压缩本构关系与时-温等效性分析-(5924)

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1、Lrelationshipofitspost-yielddeformationismoreconvenient．2．Strain￡=3．2％istheendpointofelasticstageinthestress-straincurve．Strain(￡=16％)isthepointofwoodraysstartingbuckling．Strain(￡=22％)isthepointof，vesselmolecularcellsbeginningtocrush．Strain(￡=40％)ist

2、hepointofthespecimenbeginningtocompaction．Strain(￡=65％)iscanberegardedasthecompactionpointthatcelllumenhavebeencompletelyfilled．Alongthecurveafterthecompactionpointisthecompactionstage，thestress-strainrelationsreflecttherelationshipofamaterialchangei

3、nphysicaldistancewithinthemoleculelinearly、析tlltheappliedstress．3．111eTime-TemperatureSuperpositionPrincipleissuccessfullyappliedtothepolarandtherelaxationpropertyispredicted．Forexample，themastercurveforpolartestedextrapolatedtoapproximately9．5yearsm

4、echanicalpropertiesfromlhoftestingunder10℃，30℃，50℃，70℃，90℃andRH=60％．4．nletesthadalinearhorizontal-shift—factortemperaturerelationshipandsatisfiedtheArrheniusformulation,therelationWasY=4723．7x-17．976fR=O．9848)．nle—apparentactivationenergyAEis21．6kcal

5、／mole．5．111everticalshiftfactorbrhadalinearrelationshipwithtemperature．therelationis—y2O．0045x-0．368(R2=0．9435)．ItisShowthattheexpressionofwood-temperaturesuperpositionprincipleconsideringtheverticalshiftfactorbasisthisstudyisreasonable．6．Itisagoodre

6、sultoffittingmastercurvewithlongtestmoduluscurvefor138hunderthetemperatureof10℃andtherelativehumidityof60％．Keywords：poplar,transversecompression，constitutiverelation，Time—TemperatureSuperpositionPrinciple，shiftfactorIV目录中文摘要英文摘要文献综述⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯

7、⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯．．11引言⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯．161．1杨木在压缩大变形下的力学行为⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯．161．2时一温叠加原理在木材方面的应用⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯162材料与方法⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯192．1试验设备⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯．192．2试材⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯～202

8、．3试验方法⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯．202．3．1静压试验⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯202．3．2微观构造变化观察试验⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯202．3．3时．温等效性试验⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯．．203杨木在横纹压缩下的力学行为⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯．．213．1试材与试样⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯．213．1．1静压试验试样⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯21