弯矩作用下钢轨疲劳试验研究

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1、西南交通大学硕士学位论文弯矩作用下钢轨疲劳试验研究姓名：胡家杰申请学位级别：硕士专业：机械设计及理论指导教师：刘启跃20081201AbstractWiththedevelopingofnationaleconomyandthebeginningoftheEleVenthFive．vearPIan，railwaytransportation，especiallyhighspeedrailwayconstnlctlon’lsmOreandmoreimportant．Comparedwithdevelopedcountries，ourcountry。stechnoI

2、ogyofhigh．speedrailwayisnotperfect．SomeunknownprobIemshaVebeendiscoveredinthequasihighspeedrailway，especiallyrollingcontactfatigue·Forexample，ObliqueCrackofPD3andU71Mnrailhavebeendiscovered1nGuangzhou．Shenzhenrailway．SoitisveryimportantforthedeVelopmentofourcountry，shigh．speedrailway

3、toanalysisandresearchthecrack’sinitiationandgrowth．Thenewtestrighasbeensuccessfullydevelopedbymodifyingtheclampsandthecontr01programsfromthefrettingapparatuswithhighprecision·Throughchangingofexperimentalparameters，suchasloadamplitude，loadingrate．whicheffect0nfatigueproperties，thispa

4、perresearchedfatiguepropertiesofsteeIrall．Experimentalresultshavebeenanalyzedindetailbymeansofopt童caImlcroscopyfoM)，hardnesstester，andscanningelectronmicroscopy(SEM)·MainconcIuslonsaredrawnasfollows：1、Anewexperimentalapparatushasbeendevelopedto。eallysimulateinstaUationf0哪ofrailway．Th

5、eexperimentalrealizedthenormalload，layinganexperimentaIfoundationtoresearchinginfluenceofmomentofflexure·Testscanbedone0nmodeofimposedload．TheloadingrateandloadingamplitudecanbecontrolledbVthesystemcomputer．Resultsshowedabettercompa。ablecharacteristicsandrepeatability．2、Morph0109yOfc

6、rackunderstaticloadwasgreatdifferentthanwhichunderdynamicload．Crackpropagationpathunderstaticloadappearedsuddenchange·Atthesametjme，thegrowthofcrackunderdynamicloadwasmorestablethanthatunderstaticload．西南交通大学硕士研究生学位论文第‘IIl页3、Loadingratehasdifferentinfluenceonthedifferentmaterials．PD3r

7、ailismoresensitivetoloadingratethanU71Mnrail．Undersameloadingamplitudeanddifferentloadingrate，growthofcrackofPD3railwasdifferentformU71Mnrail．4、PD3rail’SfatiguepropertieswasdifferentfromU71Mnrail’S．Underlowcycle，crackhasbeendiscoveredinPD3rail，buttherewasnocrackdiscoveredinU71Mnrail．

8、Theresultssh