پديد آورنده :
افتخاري، مجتبي
عنوان :
طراحي جاذب ارتعاشي جهت كاهش ارتعاشات غير خطي تير كامپوزيت تحت تحريك نوساني پايه
گرايش تحصيلي :
مهندسي مكانيك
محل تحصيل :
اصفهان: دانشگاه صنعتي اصفهان، دانشكده مكانيك
صفحه شمار :
چهارده،147ص.: نمودار
يادداشت :
ص.ع.به فارسي و انگليسي
استاد راهنما :
مجتبي محزون، سعيد ضيائي راد
توصيفگر ها :
اتوپارامتريك , تشديد داخلي , دوشاخه اي شدن , اشباع
تاريخ نمايه سازي :
26/1/91
استاد داور :
محمدتقي احمديان، رسول عاشقي، محمدجعفر صديق، حسن نحوي
كد ايرانداك :
ID413 دكتري
چكيده فارسي :
به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي
چكيده انگليسي :
Design of Vibration Absorber for Reducing Nonlinear Vibrations of Composite Beam Under Harmonic Base Excitation Mojtaba Eftekhari m eftekhari@me iut ac ir Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 IranDr Mojtaba Mahzoon supervisor 1 Mahzoon@shirazu ac irDr Saeed Ziaie Rad supervisor 2 szrad@cc iut ac irDr Mostafa Ghayour advisor 3 ghayour@cc iut ac irDr Mohammad Reza Salimpour Department Graduate program Coordinator Abstract Large flexible structures and aerospace structures can be modeled as flexible beams with anappendage In these structures a passive semi active or an active vibration absorber can be usedas an appendage In this work the performance of an oscillator consisting of mass and spring atthe tip of a symmetrically cantilever composite beam is investigated considering its ability toabsorb undesirable vibrations in the presence of primary resonance under chordwise baseexcitation and steady state regime The oscillator is designed at the tip of the beam in order torelate first order uncoupled modes of the composite beam through internal resonance Naturalfrequencies depend on the oscillator parameters which are selected such that two to one and one to one internal resonance be produced The motion of the combined system is described by a setof four nonlinear coupled partial differential equations corresponding to the four describingvariables of motion The equations of motion are solved using the method of multiple scales inthe occurrence of two to one and one to one internal resonances Saturation phenomenon isdetected in the force modulation response at the one to one internal resonance Reduction ofamplitudes is shown in both frequency and force response curves under primary resonance Keywords Internal resonance Composite beam Saturation phenomenon Chordwise excitation1 Introduction In structural systems nonlinearities produce interesting physical phenomena which cannotoccur in linear models One of the phenomena which can affect the response and stability ofsystems is modal interactions In the presence of modal interactions the steady state response ofa damped structure consists of the directly excited mode and large amplitude of other modes Conversely in its absence the steady state response consists of only amplitude amplification ofthe directly excited mode Therefore modal interactions cause energy transfer between modes ofa system Three energy transfer mechanisms between modes identified by Nayfeh 1 are internalresonances combination resonances or energy exchange among widely spaced modes i e nonresonant interactions Internal resonances may occur in systems where the linear natural frequencies arecommensurate or near commensurate 1 Mathematically this means that there exists integer1 Department of Mechanical Engineering Shiraz University Shiraz No 4 Molasadra Avenue Iran2 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran3 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran
استاد راهنما :
مجتبي محزون، سعيد ضيائي راد
استاد داور :
محمدتقي احمديان، رسول عاشقي، محمدجعفر صديق، حسن نحوي
