پديد آورنده :
آقابابائي، اميد
عنوان :
بررسي تقابل مودها در ارتعاشات غير خطي - غير صفحه اي تيرهاي داراي نقص هندسي و بدون كشيدگي صفحه وسط
محل تحصيل :
اصفهان: دانشگاه صنعتي اصفهان، دانشكده مكانيك
صفحه شمار :
ده، 106ص: مصور، جدول، نمودار
يادداشت :
ص.ع.به: فارسي و انگليسي
استاد مشاور :
سعيد ضيائي راد
توصيفگر ها :
رزونانس داخلي , دو شاخه اي شدن , سيكل حد , آشوب
تاريخ نمايه سازي :
2/12/88
استاد داور :
محمد تقي احمديان، مصطفي غيور، مهدي كشميري
كد ايرانداك :
ID278 دكتري
چكيده فارسي :
به فارسي و انگليسي: قابل رويت در نسخه ديجيتال
چكيده انگليسي :
Investigation of Modal Interactions in Non Linear Non Planar Vibrations of Geometrically Imperfect Inextensional Beams Omid Aghababaei o aghababai@hotmail com Date of Submission Oct 21 2009 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran H Nahvai1 Supervisor hnahvi@cc iut ac ir S Ziaei Rad2 Advisor szrad@cc iut ac ir M Keshmiri Department Graduate Program CoordinatorAbstract The equations and boundary conditions governing the non linear non planar flexural flexural torsional vibrations of isotropic inextensional beams with small geometricimperfections have been derived using Hamilton s principle The results of an experiment areincorporated to investigate the validity of the proposed model In this thesis the baseflexibility has been accounted for by modifying the proposed imperfect beam model Then by adjusting the base flexibility and geometric imperfection parameters simultaneously abetter agreement between the experimental results and theoretical predictions of the proposedmodel has been achieved The effect of small geometric imperfection on dynamic response ofresonantly base excited cantilevered beams with a one to one internal resonance has beenalso investigated by conducting a sensitivity analysis of perfect beam limit cycles to smallgeometric imperfections and dynamic bifurcation analysis of the branches of dynamicsolutions pertaining to the perfect and imperfect beams The sensitivity analysis reveals thatdepending on the frequency detuning parameter associated with each limit cycle thesensitivity to small geometric imperfections may be to a great extent Comparison ofbranches of dynamic solutions and chaotic bands associated with the perfect and imperfectbeams in a specific range of excitation frequency detuning indicates that similar dynamicbranches of perfect and imperfect beams have a frequency shift with respect to each other furthermore dynamic bifurcation points of the similar branches do not coincide completely Key Words Geometric imperfection Bifurcation Limit cycle Chaos1 Introduction The non linear dynamic response of a long slender beam has been the subject of manytheoretical and experimental efforts due to the fact that engineering structures like helicopterrotor blades spacecraft antennae flexible satellites airplane wings gun barrels robot arms high rise buildings long span bridges and subsystems of more complex structures can bemodeled as a beam like slender member In the following survey a brief summary of themost relevant works is presented Crespo da Silva and Glynn 1 investigated the flexural flexural torsional dynamics of beamsto primary resonances accounting for both geometric and inertia non linearities They foundthat the first and the second mode response curves are different and response curves for1 Associate professor2 Professor
استاد مشاور :
سعيد ضيائي راد
استاد داور :
محمد تقي احمديان، مصطفي غيور، مهدي كشميري
