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《鍛件內部空洞缺陷閉合的研究》由會員上傳分享，免費在線閱讀，更多相關內容在學術論文-天天文庫。
1、沈陽理工大學碩士學位論文摘要本文采用數(shù)值模擬和物理模擬相結合的方法對鍛件內部空洞的閉合過程進行了研究。研究結果深化了對這一問題的認識，對于采用合理的工藝方法消除鍛件內部空洞缺陷具有一定的參考價值。數(shù)值模擬采用MSC．SuperForm有限元模擬軟件，對45號鋼圓柱體鍛件的鐓粗過程進行了模擬研究。通過模擬平砧鐓粗無空洞圓柱體，給出了鍛件內部應力、應變分布情況，以及高徑比、摩擦系數(shù)對鍛件內部應力的影響規(guī)律；通過模擬平砧鐓粗帶空洞的圓柱體，模擬結果表明：空洞形狀的變化過程為球形一橢球形一裂縫，最終空洞閉合
2、，高徑比、摩擦系數(shù)是影響空洞閉合的主要因素；根據(jù)數(shù)值模擬結果，得出了空洞閉合臨界壓下率的計算公式，該公式反映了各主要因素對空洞閉合的影響規(guī)律。對于球形砧鐓粗新工藝，通過模擬球形砧鐓粗無空洞圓柱體，得到了圓柱體內應力、應變的分布情況，表明球形砧鐓粗新工藝能克服變形體內部變形不均勻和應力狀態(tài)不佳等缺陷；通過模擬球形砧鐓粗帶空洞圓柱體，得出了高徑比、凸面度對空洞閉合的影響規(guī)律；位于端面附近的空洞，球形砧鐓粗的閉合效果比平砧鐓粗的效果好。物理模擬以聚碳酸酯為原料，通過人工的方法在圓柱體心部生成空洞，對試件進
3、行了鐓粗實驗，直接觀察了空洞的閉合過程；與相同尺寸的有限元模型的數(shù)值模擬結果進行了對比分析，驗證了數(shù)值模擬的合理性。關鍵詞：空洞閉合；數(shù)值模擬；鐓租；物理模擬沈陽理工大學碩士學位論文AbstractInthispaper,numericalsimulationandphysicalsimulationwereusedtostudytheprocessofvoidclosureinforgingsduringupsetting．Theresultsofstudydeepenedtheunderstan
4、dingofthecomplicatedproblem．Thereiscertainreferencevaluetoeliminatevoiddefectsinforgingsbymakinguseofreasonableprocesses．TheMSC．SuperFormsoftwarewasusedinnumericalsimulationtoinvestigatetheupsettingprocessof45撐steelcylinderforgings．Bysimulatingtheupset
5、tingprocessofcylinderforgings晰thflatanvils，theinternaldistributionsofstressandstrain,andtheeffectsoftheratioofheighttodiameterforforgingsandfrictionconditionswereobtained．Thesimulationresultsoftheupsettingprocessofcylinderforgingswithasinglevoidwithfla
6、tanvilindicatedtheshapevariationofthevoidwassphere-'ellipse—apertureinturnandatlasttheclosureofvoid．Themaininfluencingfactorsincludedtheratioofheighttodiameterforforgingsandfrictioncondition．AcriticalreductioninheightformulaforclosureofvoidsWasobtained
7、byregressiononthenumericalresulLreflectingtheeffectsofmainfactorsonthevoidclosure．TheprocessofupsettingofcylinderforgingswithsphericalanvilWasnumericallysimulatedusingMSC．SuperFormsoftware．Accordingtothenumericalresults，thedistributionsofinternalstress
8、andstrainwerepresented．Theanalysisresultsindicatedthatthisnewtechniqueisimportantforamelioratingtheinhomogeneousdeformationanddistributionsofinternalstressandstrain．Bysimulatingtheprocessofupsettingofcylinderforgingswithasinglevoidwiths
