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1、華中科技大學(xué)碩士學(xué)位論文摘要
2、簿鰲金震管激光彎蠡
3、殘形楚一種毳瘸激光鴦囂熱來(lái)實(shí)璦梅件柔往藏形盼技術(shù),其基本癟淫是稠愛(ài)巍能激斃漿據(jù)攢金耩管表瑟,趣熬囂蠛搴
4、瓣翡熱黲聯(lián)葶
5、起孝芎料產(chǎn)生壤積,冷齠爝,該區(qū)壤耪攢滏軸淘上豹縮短,導(dǎo)致?金羼管霸肉激必素的彎黥鼓囂最終實(shí)現(xiàn)憑模成形?!瘮?shù)值模擬怒使材料科學(xué)研究由“經(jīng)驗(yàn)”迮底“科學(xué)”,凼“定性”走向“崽量”的橋梁,試驗(yàn)分析可以準(zhǔn)確的揭示新材料研究及熱加工過(guò)程中材料組織及餓能勘變化規(guī)律;數(shù)值模擬可以描述與設(shè)計(jì)許多無(wú)法用試驗(yàn)方法去展示的科學(xué)問(wèn)題。y本文以薄登金屬管激光多次掃描成形的過(guò)程為研究對(duì)象,威用有限元分析軟件ANsYS對(duì)鐓粗機(jī)理下彎曲成形過(guò)程進(jìn)行了
6、三緞數(shù)值研究。(1)建立了溫度場(chǎng)和應(yīng)力應(yīng)交場(chǎng)的有限元分析模型。該模型中考慮了材料熱物性參數(shù)的溢庹相關(guān)往,并爝小莎耀閼敞豌動(dòng)式移動(dòng)熱源模擬激光柬的連續(xù)掃描,采用變步長(zhǎng)辯闋多選取策略來(lái)縮短詩(shī)算時(shí)闊;(2)剝羯鯔S¥S中懿二次開(kāi)發(fā)潺言APDL,編寫(xiě)7建模、瓣格劃分、定爻奉孝料瓣性、灄皮場(chǎng)_穆疲力癍交場(chǎng)詩(shī)冀戇程序,實(shí)現(xiàn)了求髂過(guò)程豹鑫動(dòng)他;(3)磷究了繪定技術(shù)參數(shù)下激光彎曲湛度場(chǎng)的動(dòng)態(tài)變化過(guò)程。在光斑尺寸與衾鼴管壁厚之比比較大的情況下,上下溫差較小,滿足在鐓粗帆理下彎曲變形的前提。而激光功率,摑描速度,掃描角度和掃描次數(shù)的變化對(duì)上下溫差的影響比較小;(4)研究了給定技術(shù)參數(shù)下激光彎曲動(dòng)態(tài)應(yīng)力應(yīng)
7、變的變化過(guò)程及殘余應(yīng)力的分布,在多次掃描下,金屬管的彎曲成形過(guò)程、壁厚鐓粗以及橢圓形化的現(xiàn)象;(5)研究激光功率、掃描速度、掃描角度、掃描次數(shù)等技術(shù)參數(shù)對(duì)彎曲角的影響糯律.模叛結(jié)果表明:提高激光功率,降低掃描速度,增犬掃描角度,增加掃描次數(shù)均使彎馥角增大。(6)奩掃接速度大予一定德豹禱況下,金屬管不髓產(chǎn)生贛匈激光糶豹彎益。華中科技大學(xué)磺士學(xué)位論文ABSTRACTLasertubebendingisaflexibleformingprocessbywhichmetaltubecallbebentwithoutexternalforces.Itisgenerallyknownthatla
8、serbendingoftubesisachievedthoughtupsettingmechamsm.Thescannedregionofthetubeisheatedalmosthomogeneouslyinthethicknessdirection,andundergoescompressiveplasticdeformationandwallthickeningduetorestrictiononthermalexpansionbythesurroundingmaterial.Themajorprobleminthestudyoflaserbendingistounderst
9、andthetemperatureandstress-straindistributionatdifferentprocessparametersandscanningpaths.Numericalsimulationisthewayformexperiencetotheoryandqualitativeanalysistoquantitativeanalysisinthematerialfield,ThevariationrulesofmicrostructureandperformanceCallbeaccuratelyshowedthroughtheexpedment.Nume
10、ricalsimulationcandescribeanddesignmanyscientificproblemswhichcannotbesolvedbyexperiments.FEMishi#yrecognizedforitsabilitytoinvestigatethetemperaturefieldandstress—strainfield.Inthisdissertation,three-dimensionalnumericalresearchesontubelaserbendingundertheupsettingmechanismalecarriedoutwithANS
11、YSsoRware一一(1)Afiniteelementmodeloftemperaturefieldandstress-strainfieldisbuilt.Inthismodel,thetemperaturedependencyofthethermalandmechanicalpropertiesofthemateriala托considered。asmall-paceintermittentheatsourceisadoptedtosimulatet