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1、汽車右托架熱拉深數(shù)值模擬及工藝參數(shù)優(yōu)化摘要高強(qiáng)度鋼以其本身固有的高強(qiáng)度、低回彈量和良好的碰撞特性被國內(nèi)外廣泛應(yīng)用于汽車制造領(lǐng)域,成為實(shí)現(xiàn)汽車輕量化,提高汽車被動安全性的重要途徑之一。但在國內(nèi)對在溫?zé)釥顟B(tài)下成形工藝的研究較少,主要因?yàn)樵谑覝叵缕涑尚涡阅茌^差。本文采用數(shù)值模擬和灰色理論相結(jié)合的方法對汽車右托架熱拉深成形進(jìn)行了研究。運(yùn)用彈粘塑性有限元法有效分析了壓邊力加載方式、拉延筋、模具和板料初始溫度、沖壓速度等工藝參數(shù)對成形質(zhì)量的影響。研究表明隨著模具和坯料初始溫度的升高,成形時的變形抗力明顯下降,流動應(yīng)力
2、降低,成形質(zhì)量顯著提高;V型壓邊力曲線最有利于成形;拉延筋的凸筋、凹筋圓角半徑越小、筋高越大,則板料在成形時出現(xiàn)破裂的趨勢增大;隨著沖壓速度的增大,板料的冷卻時間縮短,成形過程中產(chǎn)生的內(nèi)應(yīng)力減小。在500℃時,通過正交試驗(yàn)設(shè)計,運(yùn)用灰色系統(tǒng)理論對壓邊力和拉延筋幾何參數(shù)進(jìn)行優(yōu)化,得出最優(yōu)的工藝參數(shù)組合為:壓邊力為82KN,拉深筋高度為2mm,凸筋圓角半徑為4mm,凹筋圓角半徑為6mm。將最優(yōu)工藝參數(shù)下的成形模擬結(jié)果與正交試驗(yàn)中最優(yōu)的一組模擬結(jié)果進(jìn)行了對比,表明板厚變薄率更加均勻,起皺趨勢有所減小,破裂趨勢明
3、顯降低,成形質(zhì)量顯著提高。最終達(dá)到了預(yù)期設(shè)計目標(biāo),表明將模擬成形和灰色系統(tǒng)理論相結(jié)合的方法研究復(fù)雜覆蓋件成形,具有一定的理論和實(shí)際工程意義。關(guān)鍵詞:高強(qiáng)度鋼板;熱拉深;數(shù)值模擬;灰色系統(tǒng)理論;覆蓋件TheHotStampingFormingSimulationofVehicle’SRightBracketandOptimizationDesignofProcessParametersABSTRACTCharacterizedbyitsinherenthighstrength,lowspringbackan
4、dgoodbump,thehighstrengthsteelwaswidelyemployedforauto—manufacturingsectorinforeigncountries.Theuseofhighstrengthsteelalsobecameamajorchannelofrealizingtheautomotivelightweightingandimprovingthepassivesecurity.However,therewasrelativelylittleresearchonitm
5、ainlybecauseofitspoorformingcapabilityinroomtemperature.Basedonthenumericalsimulationandgraysymtemtheory,thepaperconductsaresearchonthehotformingprocessofvehice’Srightbracket.Theauthoranalysestheinfluenceoftheprocessparametersontheresultofforming,whichinc
6、ludeloadmodeoftheblankholdingforce,drawbead,initialtemperaturesoftheblankandmould,thestampingvelocityetcbytheelastic—viscoplasticFEMsimulation.Thefindingsthestudycansuggestasfollows:Theresistanceofdeformationandtheflowstresswillreducewhiletheformingqualit
7、yobviouslywasimprovedwithanincreaseofinitialtemperatureofmouldandblank;Vshapecurveofblankholdingforceisthebestchoicetoforming;Thepossibilitytoappearcrackwillincreasewithdecreasingoftheroundradiusofthedieandpunch;Theinnerstresswillreducewhilethestampingvel
8、ocityincreasing.Whenthetemperatureis500℃,theauthoroptimizethegeometryparametersofdrawbeadandtheholdbinderforcebasingontheorthogonalexperimentsdesign.Thebestoptimzationparametersareasfollws:theholdbinderforceis82KN,t