4385

4133

كارشناسي ارشد

طراحي كاربردي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مكانيك

1387

ده ،122،[II]ص :مصور ،جدول ،نمودار

ص.ع .به: فارسي وانگليسي

مهندسي مكانيك

ID4133

به فارسي وانگليسي: قابل رويت درنسخه ديجيتال

AbstractMistuning imperfections in cyclical symmetry of bladed disks is an inevitable andperilous occurrence due to many factors including manufacturing tolerances and inservice wear and tear It can cause some unpredictable phenomena such as modesplitting mode localization and dramatic difference in forced vibration response Thissurvey explains the fundamental techniques of mistuning in some details For thisobject a comprehensive concept of the worst specification is evaluated andformulated as an optimization problem Then the worst case optimization problem isutilized for different models like lumped models and large finite element models Intentional mistuning as well as rearranging method as an optimization problem isused to reduce the bad effects of mistuning on the forced vibration response of bladeddisk system Then the genetic algorithm is used for solving all optimizationproblems Next the efficiency of methods is demonstrated for two different lumpedparameter models Afterward the formulation of 3D finite element bladed disk modelis explained Then the free and forced vibration response of a 3D sample BD model isevaluated Next component mode synthesis CMS as a reduce order method ROM is used to for finding the forced vibration response of both tuned and mistuned BDsystems For this object a novel method is presented that can be used for both smalland large mistuned systems An approximation is utilized to evaluate the harmonicresponse of small mistuned system The results of novel method are compared to theresults evaluated by previous complicated methods like Craig Bampton CB method Subsequently the effects of mistuning on nonlinear mistuned cyclical symmetricsystems like BD are shown The method of multiple scales is used for finding theforced and steady state vibration response of a nonlinear mistuned lumped model Finally the aeroelastic behavior of mistuned bladed disk is evaluated by use of panelmethod as an aerodynamic model and consequently the bad effect of mistuning onflutter speed is shown

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حسن نحوي ،مصطفي غيور