پديد آورنده :
محمدي، حميد
عنوان :
بررسي ارتعاشي پانل هاي موج دار به كمك حل اجزاي محدود
مقطع تحصيلي :
كارشناسي ارشد
محل تحصيل :
اصفهان: دانشگاه صنعتي اصفهان، دانشكده مكانيك
صفحه شمار :
[هشت]،78ص.: مصور،جدول،نمودار
يادداشت :
ص.ع.به فارسي و انگليسي
استاد راهنما :
سعيد ضيايي راد
استاد مشاور :
محمود كدخدايي
توصيفگر ها :
هسته هاي موج دار , فلاتر , آلياژهاي يادآورنده ي پيكره ي نخستين
تاريخ نمايه سازي :
1/9/93
استاد داور :
حميدرضا ميردامادي، عليرضا شهيدي
چكيده فارسي :
چكيده بررسي رفتار مكانيكي و رتعاشاتي پانلهاي موجد ر در صنعت هو فضا د ر ي هميت بسيار ست ين پانلها در ساختارهايي كه نياز به تحمل بار و تغيير شكلهاي بزرگ و وزن سبك د رند بهصورت گسترده ستفاده ميشوند چنين پانلهايي معمولا د ر ي هستهي موج د ر كامپوزيتي هستند هدف ز ين پروژه بررسي و مطالعهي رفتار رتعاشي هستههاي موجد ر تحت نيروي آيروديناميك به كمك حل تحليلي و لمان محدود ست ز ين رو بتد به منظور رزيابي ويژگيهاي رفتار رتعاشي ين پانلها مدل لمان محدود آن در نرم فز ر آباكوس تهيه گرديد و تحت بارگذ ري آيروديناميك قر ر گرفت در بررسي پاسخ پانل به ين نيرو پديده فلاتر در آن مشاهده شد سپس بر ي بررسي بيشتر مدل سادهتري ز ين پانلهاي موجد ر به شكل يك ورق عمودسانگرد پيشنهاد شد بر ي ين منظور نرژي تغيير شكل يك پانل موجد ر با يك ورق عمودسانگرد با طول و عرض يكسان بر بر قر ر د ده شد و ضر يب مورد نياز بر ي زمينه سختي ورق بهگونه بهدستآمد كه هر دو تحت بارگذ ر يكسان جابهجايي يكسان دهند پس ز آن با قر ر د دن ورق معادل تحت بارگذ ري يكسان با مدل لمان محدود پانل و بررسي پاسخ ورق پديدهي فلاتر در ين ورق مشاهده شد بررسي خصوصيات فلاتر هر دو مدل مانند د منه نشان د د كه نزديكي خوبي بين پاسخهاي ين دو مدل وجود د رد در نتها با ضافه كردن سيمهايي ز جنس آلياژهاي يادآورنده پيكره نخستين به مدل پانل نشان د ده شد كه ميتو ن به كمك ين آلياژ د منه رتعاشات ر كاهش د د ين پديده نشان ميدهد كه ين آلياژها گزينه مناسبي بر كنترل رتعاش هستند كلمات كليدي هستههاي موجد ر فلاتر آلياژهاي يادآورنده پيكره نخستين 1 Flutter 2 Orthotropic
چكيده انگليسي :
Vibration Analysis of Corrugated Panels by Finite Element Method Hamid Mohammadi E mail hamid mohammadi@me iut ac ir Date of submission June 11th 2014 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language Persian Supervisor Dr Saeed Ziaei Rad E mail szrad@cc iut ac irAbstractSome important advantages of composite materials such as their high weight to strength ratio was the causeof their prevalent use in many industrial cases in past decades Corrugated panels are special kinds ofcomposite structures that their ability to withstand loads in one direction and be flexible in other direction hasmade them suitable for morphing structures The principal application of this type of composite structures isin the morphing airfoils where they are subjected to the aerodynamic loading in various flow regimes Sincemany researches on the static and dynamic behavior of such interesting structures were reported in theliterature having a comprehensive insight into their aeroelastic behavior is of crucial importance Considerable amounts of researches were done that focused on static and dynamic behavior of these specialcomposite panels subsequently the main goal of the present study is to determine time response intoarerodynamic loading and stability analysis of corrugated composite panels An equivalent analytical modelto characterize the trapezoidal corrugated core is presented A complete set of analytical formulas wasderived based on energy approach for elastic modulus in different directions transverse and in plane shearmodulus in plane Poisson s ratio and mass density of the equivalent model The proposed approach isgeneral and able to model different corrugation geometry parameters overcoming the main limitation of theexisting analytical formulations To validate the precision and accuracy of the derived formulation obtainedresults were compared with the reported results in literature as well as the finite element simulations Afterwards using the proposed model in conjunction with Hamilton principle and considering first orderquasi steady aerodynamic theory linearized piston theory as a simple and suitable method for aerodynamicloading in supersonic flow regime time responses of the panel FFT and phase diagrams of were obtained Then an aeroelastic finite element model were provided in ABAQUS an FEM package to evaluate thevalidity of the results obtained by Galerkin In this FE model the panel was modeled as a shear deformablecomposite shell considering the effect of large out of plane displacements due to its nonlinear geometry Considering the fact that ABAQUS dose not have the capability to apply a kind of loading that is dependent totime and spatial derivatives of out of plane translational DoF linearized piston theory as a typical loading aDLOAD FORTRAN subroutine were provided to apply the aerodynamic loading The results of these analysisshowed that the motion of the panel would be eather simple harmonic or non harmonic but periodic limitcycle oscillations A comparison between Galerkin approach and FEM results were made and acceptableagreement were demonstrated Furthermore the effects of shape memory alloys on vibration of corrugatedpanels were also studied Keywords Corrugated composite structures Finite element method Limit cycleoscillations Linerized piston theory Morphing airfoils Shape memory alloy Homogenization technique and Supersonic flow regime
استاد راهنما :
سعيد ضيايي راد
استاد مشاور :
محمود كدخدايي
استاد داور :
حميدرضا ميردامادي، عليرضا شهيدي