مدل سازي و آناليز ارتعاشي ورق مركب لايه به لايه پيزوالكتريك/ويسكو الاستيك﴿ACLD﴾ به روش المان محدود طيفي

چكيده انگليسي :

Modeling and Vibration Analysis of A Laminated Viscoelastic Piezoelectric Composite Plate ACLD with Spectral Finite Element Method Hesam Hajheidari h hajheidari@me iut ac ir 2011 06 06 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor Hamidreza Mirdamadi hrmirdamadi@cc iut ac irAbstract The spectral element model is known to provide very accurate structural dynamic characteristics whilereducing the number of degree of freedom to resolve the computational and costs problems In this thesis first aformulation of a spectral element for a cross ply laminated composite plate has been presented Then spectralelement model for a composite plate with active constrained layer damping ACLD has been developed Thespectral finite element method SFEM formulation in this thesis begins with deriving the fully coupled dynamicequations of motion by using Hamilton s principle Unlike the 1 D beam structures two dimensional 2 D plate structures show much more complicated wave characteristic Thus developing the spectral element modelsfor the plates with general boundary conditions is not so straightforward and some approximations may benecessary Therefore in this thesis the spectral element modeling has been introduced only for the levy typelaminated composite plates and the plate 2 D problem has been transformed to the equivalent beam like 1 Dproblem Using finite strip method FSM the plate has then been considered as a connection of several strips spectral plate element with the joint node line along which the equivalent line load acts The spectral plateelement has been formulated with the exact solution to of a set of the equivalent 1 D coupled dynamic equationsof motions in the frequency domain This exact solution has been used as interpolating function for spectralelement formulation The use of exact solution in the element formulation ensures exact mass and stiffnessdistribution Then the spectral plate element matrix dynamic stiffness matrix has been formulated from therelations between the forces and displacements along the opposite two parallel edges Finally the frequencydomain responses have been transformed to time domain using inverse fast Fourier transform IFFT In thisresearch both free vibration and forced vibration is performed using the formulated elements for a cross plylaminated composite plate The high accuracy of the spectral element model has then been verified bycorresponding results from conventional finite element solutions and exact analytical solutions naturalfrequencies and the dynamic response to high frequency transients The results are indicated that spectral finiteelement method can model structural dynamic characteristics with smaller element and higher accuracy incomparison with the results of the conventional finite element method The SFEM formulation of an ACLDplate has been verified with the analytical solution In addition the performance of an ACLD plate isinvestigated with proportional derivative controller and the results obtained indicate that the ACLD treatmentsare very effective in damping the structural vibration as compared to the conventional PCLD This isparticularly true at low frequencies when proportional controllers are used and over a wider frequency ban whenthe controllers are augmented with a derivative component Key Words Structural Dynamic Laminated Composite Plates Spectral Finite Element Method SpectralElement Matrix Dynamic Shape Function Active Constrained Layer Damping Finite StripMethod Proportional Derivative Controller

حاج حيدري، حسام

مدل سازي و آناليز ارتعاشي ورق مركب لايه به لايه پيزوالكتريك/ويسكو الاستيك﴿ACLD﴾ به روش المان محدود طيفي

ديناميك سازه هاي ماتريس المان طيفي , تابع شكل ديناميكي , ميراگرهاي دوگان فعال-غير فعال , روش نوار محدود , كنترل كننده مشتقي تناسبي