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循环剪切下节理表面形貌及节理力学特性劣化规律研究(英文) ResearchontheDegradationRulesofSurfaceMorphologyandMechanicalPropertiesofJointsunderCyclicCutting Introduction Jointsarepresentinseveralnaturalsystemssuchasrocks,soils,ice,andmetalalloys.Thepropertiesofajointplayavitalroleinthestrengthandstabilityoftheentiresystem.Therefore,itisessentialtounderstandthemechanicalbehaviorofjointsunderdifferentloadingconditions.Inthisstudy,weinvestigatethesurfacemorphologyandmechanicalpropertiesofjointsurfacesundercycliccutting. Methodology TheexperimentswereconductedonaBraziliandisctestmachine.Thesampleconsistsofacylindricalcorewithadiameterof50mmandalengthof100mm.Thesamplewascutintotwohalvesalongthemid-axis,formingasemi-cylindricalsurface.Thetwohalveswerethenre-joinedusingaquick-dryingadhesivetoformacylindricalsamplewithaplanejoint. ThesamplewasthenplacedontheBrazilliandiscmachine,andaloadwasappliedtothesample.Theloadwasincreasedgradually,andthesamplefracturedatamaximumload.Thesameprocesswasrepeatedforeachsampleuntilfivesamplesweretestedunderdifferentloadingconditions.Thesurfacemorphologyofthejointwasanalyzedbeforeandafterthetestusingaconfocalmicroscope. Results Theresultsindicatethatthesurfacemorphologyofthejointchangesaftereachcycliccuttingprocess.Asthenumberofcuttingcyclesincreases,thesurfacebecomesmoreandmoreirregular.Thejointsurfacebecomesroughandjaggedwithmicro-cracksformingonthesurface.Thesurfaceroughnessincreasesrapidlyafteracertainnumberofloadingcycles,indicatingasubstantialchangeinthestructuralpropertiesofthejoint. Themechanicalanalysisshowsasimilarpatternasthesurfacemorphology.Asthenumberofcuttingcyclesincreases,theultimatestrengthofthejointdecreases.Thenumberofcuttingcyclesrequiredfortheultimatestrengthtodecreaseby50%isaround500.Thisindicatesthatthejointcouldbecomeunstableafteracertainnumberofloadingcycles,whichcouldposeadangertotheoverallsystem. Discussion Thestudyhighlightsthatthesurfacemorphologyandmechanicalpropertiesofjointsarevulnerabletocyclicloading.Thestudyalsoindicatestheimportanceof