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ID:34124827
大小:12.72 MB
页数:56页
时间:2019-03-03
《焦炭塔用材15crmor低周疲劳寿命试验分析》由会员上传分享,免费在线阅读,更多相关内容在行业资料-天天文库。
1、万方数据万方数据万方数据河北工业大学硕士学位论文摘要焦炭塔是延迟焦化工艺中的关键设备,其工作环境恶劣,在反复的交变载荷和温度变化的条件下,筒体环焊缝附近容易发生鼓胀、开裂,影响设备的安全运行,因此对焦炭塔用材低周疲劳寿命进行研究非常重要。本文制作了焦炭塔用材15CrMoR对接试件,对其母材区及焊缝区金属进行了不同温度的单轴拉伸试验和全寿命单轴棘轮效应试验。通过单轴拉伸试验得出预测低周疲劳寿命的基本参数,选用考虑棘轮效应的MSRS模型对母材区和焊缝区材料疲劳寿命进行预测,预测结果均在2倍误差带以内,而且预测结果均匀分布在45°精确线两侧。选用OW-
2、II随动强化本构模型,得出在相同工况下母材区焊缝区稳定段的棘轮应变率和应变幅值,并将其带入MSRS模型,结果表明,母材区疲劳寿命明显低于焊缝区,母材区稳定段棘轮应变率明显高于焊缝区。对焦炭塔用材15CrMoR试件进行了全寿命的多轴棘轮效应试验,分别考察不同加载路径、剪切应变幅值、平均应力、应力幅值对材料试件多轴棘轮效应及疲劳寿命的影响;并利用等效应变法、临界面法、能量法、考虑棘轮效应的预测模型,对材料多轴疲劳寿命进行预测,通过对比,考虑棘轮应变修正项的Gao-Chen模型对15CrMoR多轴疲劳寿命的试验结果给出了很理想的预测效果。关键词:15C
3、rMoR,棘轮效应,低周疲劳,多轴寿命预测I万方数据焦炭塔用材15CrMoR低周疲劳寿命试验研究ABSTRACTCokedrumisthekeyequipmentofthedelayedcokingprocess.Duetoitspoorworkingconditions,barrelandgirthweldpronetobloatingandcrackingaffectsthesafeoperationofequipmentatrepeatedalternatingloadandthechangingtemperaturecondition.T
4、herefore,Sochooseappropriatemodeltosimulatethecoketowermateriallowcyclefatiguelifepredictionisveryimportant.Butt-weldspecimenhasbeenmadeforcokedrummaterial15CrMoR.Forbothparentandweldmaterials,uniaxialtensiletestsanduniaxialratchetingtestshavebeenconductedunderdifferenttemper
5、atures.TheOW-IIkinematichardeningconstitutivemodelhasbeenusedtopredictthematerialratchetingeffectusingtheexperimentaldataobtained.TestresultsshowthattheOW-IImodelcanwellpredictratchetingstrainratesforthestableperiod.Basedontheobtaineduniaxialtensiletestdata,basicparametersfor
6、predictinglowcyclefatiguelifehavebeenobtained.TheMSRSmodelhasbeenusedtopredictthefatiguelivesoftheparentmaterialandweldmetal.Thepredictedresultsarewithinthe2timeserrorbandandareuniformlydistributedonbothsidesof45°lineaccurately.Furthermore,theratchetingstrainrateandthestraina
7、mplitudeforthestableperiodareobtainedfortheparentmetalandtheweldmetalrespectivelybytheOW-IIkinematichardeningconstitutivemodelunderthesameconditions.TheMSRSmodelpredictsthatthefatiguelifeoftheparentmaterialissignificantlylowerthanthatoftheweldmetalandduringthestableperiodther
8、atchetingstrainrateofparentmaterialissignificantlyhigherthanthatofth
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