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简介：Carbon-manganesesteelisoftenappliedincomponentsofpipesinnuclearplant.Ultrasonicfatiguetestsfollowinglowcyclefatigue(LCF)cyclesdamagedareusedtostudythestrengthofveryhighcyclefatigure(VHCF).ThecomparisonoftestresultsofsimpleVHCFandcumulativefatigue(LCFplusVHCF)showsthatLCFloadinfluencesthefollowingVHCFstrength.ContinuumdamagemechanicsmodelisextendedtoVHCFregion.TheeffectofLCFloadonVHCFisstudiedbyanimprovedcumulativedamagemodel.

简介：疲劳失败长是为轮船的一个重要问题并且近海结构。在为预言疲劳生命的众多的方法之中，光谱方法作为最可靠被接受。尽管在光谱分析后面的理论是直接的，因为它仔细与象疲劳的申请那样的批评技术细节有关正在装载，分析本身复杂、费时间(由于货物挥动压力和惯性的力量)，压力的抽取，并且压力RAO的计算。这里，四关键装载technicaldetails应用，排水量边界条件，压力RAO的计算，和疲劳压力的抽取彻底地讨论了。为每个方面，分辨率基于有限元素pre被介绍--并且processing以后软件MSC/PATRAN或FEsolverMSC/NASTRAN。决定有效、有效，它能帮助工程师表现光谱精确地并且更快使分析疲劳。

简介：Amodelisproposedtocorrelatethecrackgrowthrateandstressratiocontainingveryhighcyclefatigueregime.Themodelisverifiedbytheexperimentaldatainliterature.Thenaformulaisderivedfortheeffectofmeanstressonfatiguestrength,anditisusedtoestimatethefatiguestrengthofabearingsteelinveryhighcyclefatigueregimeatdifferentstressratios.TheestimatedresultsarealsocomparedwiththosebyGoodmanformula.

简介：AbstractBackground:Many Parkinson disease (PD) patients complain about chronic fatigue and sleep disturbances during the night. The objective of this study is to determine the relationship between fatigue and sleep disturbances by using polysomnography (PSG) in PD patients.Methods:Two hundred and thirty-two PD patients (152 with mild fatigue and 80 with severe fatigue) were recruited in this study. Demographic information and clinical symptoms were collected. Fatigue severity scale (FSS) was applied to evaluate the severity of fatigue, and PSG was conducted in all PD patients. FSS ≥4 was defined as severe fatigue, and FSS <4 was defined as mild fatigue. Multivariate logistic regression and linear regression models were used to investigate the associations between fatigue and sleep disturbances.Results:Patients with severe fatigue tended to have a longer duration of disease, higher Unified Parkinson Disease Rating Scale score, more advanced Hoehn and Yahr stage, higher daily levodopa equivalent dose, worse depression, anxiety, and higher daytime sleepiness score. In addition, they had lower percentage of rapid eye movement (REM) sleep (P = 0.009) and were more likely to have REM sleep behavior disorder (RBD) (P = 0.018). Multivariate logistic regression analyses found that the presence of RBD and proportion of REM sleep were the independent predictors for fatigue. After the adjustment of age, sex, duration, body mass index, severity of disease, scores of Hamilton Rating Scale for Depression, Hamilton Anxiety Rating Scale, and other sleep disorders, proportion of REM sleep and degree of REM sleep without atonia in patients with PD were still associated with FSS score.Conclusion:Considering the association between fatigue, RBD, and the altered sleep architecture, fatigue is a special subtype in PD and more studies should be focused on this debilitating symptom.

简介：Intheapplicationsofaircrafts,automobiles,railways,biomedicineandoff-shorestructures,manycomponentsmayexperiencecyclicloadingconditionsoveralongperiodoftime,runninguptoseveralhundredmillioncycles.1Determinationoflonglifefatiguebehaviorbecomesextremelyimportantforbetterunderstandinganddesignofcomponentsandstructures.

简介：Withtheloadingtestequipmentofcorrosionfatiguespeciallydesigned,thecorrosionfatiguecharacteristicsofhighperformanceconcrete(HPC)withstandingtheinteractionofthirdpointfatigueloadingandNa2SO4solutionwereinvestigatedandanalyzed.Theexperimentalresultsindicatethatwater-binderratioevidentlyinfluencesthecorrosionfatiguecharacteristicsofHPC,andamoderatequantitativefinemineraladmixtureenhancesthecorrosionfatigueresistanceofHPC.Theeffectismoresignificantwhenflyashandsilicafumeareadded.

简介：Fatiguecuttingisanewapproachforseparatingmaterial.Man-madefatiguecanberealizedbyapplyingarotatingbendingloadtoanotchedbar.Tobetterutilizethenewmethod,lasertreatmentisadoptedinthisstudy.Afterlaserradiationatthenotchroot,thefatiguecycleofthebardropsdramatically.Basedontheexperimentalresult,wedrawtheconclusionthatthefatigueofthebarisinfluencedbytheshapeofthehardenedarea.Ahardenedareathathasasmallaxialdimensionandarelativelylargeradialdimensionfacilitatesthefatigue.Thedesirablehardenedareacanbeobtainedbycontrollingthelasertreatmentparameters.

简介：Veryhighcyclefatiguebehaviorsoftwobainite/martensitedual-phasesteelswereinvestigated.Oneofthesteelswascyclicrapidheattreatedanditsmicrostructureswererefined.Fatiguestrengthofthesteelis225MPahigherthanthatwithoutrefining.Observationoffracturesurfacesshowthatthefatiguecracksinitiateatbainitesfornon-refinedsteelandatnon-metallicinclusionsfortherefinedsteel.Thesizeofinclusionsismuchsmallerthanthatofbainiteswhichresultsintheimprovementoffatiguestrength.

简介：ThefatiguebehaviorofweldedstructuresiscurrentlydeterminedbymeansofrecommendationsdefinedintermsofS-Ncurvecorrespondingtothedetailclassesofweldedjointswithouttakingaccountoftheactualgeometryoftheweld.AnewfatiguestrengthassessmentmethodbasedonDangVanmultiaxialfatiguelimitcriterionwasintroduced,whichisnamedthelocalapproachandpresentedbyInstitutdeSoudurerecently.Thelocalapproachhasadvantagesintakingweldingresidualstressesandthegeometryoftheweldtoeandweldrootintoconsideration.TheapplicationofthelocalapproachtothefatiguestrengthassessmentoflowcarbonsteelQ235Bweldedjointswasstudied.ThefatiguetestsandfiniteelementanalysisresultsshowthatthelocalapproachparametersrecommendedbyInstitutdeSoudurewereincorrectlyforlowcarbonsteelQ235Bweldedjoints.Withaluminumalloyweldedjointsbeingusedwidely,theparametersofthelocalapproachusedforaluminumalloyweldedjointswereobtainedandverifiedonbasesofthefatiguetestsandfiniteelementanalysis.

简介：目的：分析针灸防治运动性疲劳的临床和实验研究文献，了解针灸消除运动性疲劳的研究现状。方法：利用文献分析法，整理了的20年来治疗为主治疗运动性疲劳的文献，进行了归纳分析。结果与结论：针灸可能通过清除自由基、抗脂质过氧化，防止运动性下丘脑-垂体-幽泉轴功能紊乱，降低肌酸激酶（CK）含量，降低乳酸浓度等作用，对消除运动性疲劳、改善机体运动能力有重要作用。但因传统的针灸疗法会对机体产生微小损伤，故今后应注重推广无创痛穴位疗法，并从多途径多环节探索针灸防治运动性疲劳的作用机制。

简介：Learningiswidelyusedinintelligentplanningtoshortentheplanningprocessorimprovetheplanquality.Thispaperaimsatintroducinglearningandfatigueintotheclassicalhierarchicaltasknetwork(HTN)planningprocesssoastocreatebetterhighqualityplansquickly.TheprocessofHTNplanningismappedduringadepth-firstsearchprocessinaproblem-solvingagent,andthemodelsoflearninginHTNplanningisconductedsimilartothelearningdepth-firstsearch(LDFS).Basedonthemodels,alearningmethodintegratingHTNplanningandLDFSispresented,andafatiguemechanismisintroducedtobalanceexplorationandexploitationinlearning.Finally,experimentsintwoclassicaldomainsarecarriedoutinordertovalidatetheeffectivenessoftheproposedlearningandfatigueinspiredmethod.

简介：NickeliscommonlycoatedontheouterleadsforT8metalpackage.Theleadselectrodepositedbyconventionaldullorbrightnickelover5μmatdirectcurrentfromWattbatharehardtopassthebendfatiguetestforthreetimes.Nickelelectrodepositedatmultiwaveformcurrentincludingdirectcurrent,singleanddoublepulsefromsulfamatebathcanimprovethebendfatiguestrengthofleads.Suchnickelplatinghasamultilayerstructure,itsmorphologyofsublayerscanbeclearlyseeninitscrosssectionwithSEM.Theelectrochemicalstudyshowsthatthesesublayershavedifferentcorrosionpotentials.ThebendfatiguetestofleadswithsuchplatingforT8metalpackageshowsthatthenumberofbendincreaseswiththedecreaseofaveragecurrentdensityofmultiwaveform,whichcanbeattributedtothereductionofeverysublayerthicknessandtheincreaseoflayernumbersunderthesameconditionoftotalthickness.

简介：First,Wirsching＇smodel,whichiswidelyemployedinfatiguereliabilityanlysisofmarineandoffshorestructures,isanalysedsystematically.Itisfoundthattheveryimportantrandomvariable△inWirsching＇smodelcannotbedirectlydeterminedfromfatigueexperimentbecauseoftheirreversibilityoffatiguetest,andinfact,whatWirschingstudiedfromtestingresultsisnot△butαofthestatisticalMiner＇srule.Second,byuseofthestatisticalMiner＇srule,amodifiedWirsching＇smodelisproposed.Thirdlyandmoreimportantly,basedonthetwo-dimensionalprobabilisticMiner＇srule,anewmodelisestablishedforfatiguereliabilityanalysisofstructuralcomponentssubjectedtospecifiedcyclicloadingofvariableamplitudeorstochastictimehistory.Intheend,anexampleispresented,fromwhichitwillbeseenthatthisnewmodelisveryconvenienttouseandfeasibletoengineeringpractice.

简介：Theergonomicdigitaldesignandevaluationofman-machinesystemisthemainapplicationfieldsofvirtualhumantechnology.Becauseofthecomplexityofphysicalpersonanduncertaintyoffatiguegenerationmechanism,itisdifficulttoexpressandevaluatetheVirtualHuman'sfatiguestate.Thispapersummarizesthecharacteristicsofvirtualhuman'sfatigueevaluation,suchasundeterminable,invisible,theconstraintconditionscanbeenused.Viewedfromthestrengthsandweaknessesofpreexistingmodels,metabolicenergyexpendituremodel,dynamicmusclefatiguemodelandamodeltoassessfatigueatjoint-levelusingthehalf-jointconcept,thispaperputsforwardthefuturedevelopmenttrendthatthecombinationofsubjectiveandobjective,diversificationoftheanalyzablemotion,real-timeandvisualexpression.

简介：Thefatiguelifeofnumerousaerospace,locomotive,automotiveandbiomedicalstructuresmaygobeyond10~8cycles.Determinationoflonglifefatiguebehaviorbecomesextremelyimportantforbetterunderstandinganddesignofthecomponentsandstructures.Initially,beforetheinventionofultrasonicfatiguetesting,mostoftheengineeringmaterialsweresupposedtoexhibitfatiguelifeupto10~7cyclesorless.Thispaperreviewscurrentunderstandingofsomefundamentalaspectsonthedevelopmentofacceleratedfatiguetestingmethodanditsapplicationinultra-highcyclefatigue,crackinitiationandgrowthmechanismsofinternalfracture,S-Ndiagram,fatiguelimitandlifeprediction,etc.

简介：Asimplifiedfatigue-lifemodelisproposedforassessingtheseismicinelasticrotationalcapacityofsteelconnections.Firstrelationsaredevelopedforrigidsteelconnectionsunderlateralloading.Nextthisisextendedtoaccountfortheeffectsoftheweldedsteelmomentframe(WSMF)connectionsoftheso-calledpre-Northridgetype.Theseismicfatiguetheoryisvalidatedagainstexperimentalresults.Theexperimentswereconductedunderincreasingductilityamplitudcsuntiltheonsetoffracture.Miner'rulewasusedtoconvertthetestresultstogivenanequivalentconstantamplitudecyclicfatiguelife.Satisfactoryagreementisobtainedwhencomparingtheexperimentalobservationswiththetheoreticalpredictions.

简介：Thedeterminationofstructuraldynamicstressspectrumdistributionisofgreatsignificanceinthestructuralfatiguestrengthevaluationaswellasreliabilitydesign.Inpreviousempiricaldataprocessingmethods,thedatagroupinganddistributionfittingwereexcessivelycoarseandcontaineddistinctivedefects.Thispaperproposedaneffectiveapproachtostatisticallygroupactualmeasureddynamicstressdataandvalidlyextrapolatethecombineddistributiontofitthedynamicstressspectrumdistribution.Thisapproachhasbeenverifieditseffectivenessthroughchi-squaretest,stressspectrumextrapolationanddamagecalculationindynamicstressstudy.

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简介：Structuralintegrityisstatedasthescienceandtechnologyofmarginbetweensafetyanddisaster.Systematicpredictionofstructuralintegrityofcriticalstructuressuchascombustionchambers,pressurevessels,nuclearreactorcomponents,boilersetc.,ensuresthehumansafety,environmentalprotection,andtheeconomicalconsiderations.Thepresentworkaimsatpredictionoffatiguebehaviourofsymmetricstructureslikepressurevesselsinthepresenceofcommonweldingdefectssuchaslackoffusion(LOF),lackofpenetration(LOP)andporosity.Aringtypespecimenwhichreplicatesthestresspatterninthepressurevesselisconsideredforthestudyofseverityofweldimperfections.InitialdimensionsofwelddefectsarearrivedbyperformingNDTinspection.Crackgrowthanalysisiscarriedouttodeterminetheremaininglifeoftheweldedjointwithdefects.