10933

835 دكتري

دكتري

مكانيك

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مكانيك

1394

يازده،109ص.: مصور

حسن نحوي، جمشيد پرويزيان

حميدرضا ميردامادي

1394/10/29

بيژن برومند، محمود فرزين، مهرداد پورسينا، محمد مشايخي

مهندسي مكانيك

ID835 دكتري

110 Dynamic simulation of systems under high frequency excitation using finite cell method Yaser Mirbagheri y mirbagheri@me iut ac ir Date of Submission 2015 11 4 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree Ph D Language Farsi1st Supervisor Hassan Nahvi hnahvi@cc iut ac ir2nd Supervisor Jamshid Parvizian japa@cc iut ac irAdvisor Hamid Reza Mirdamadi Department Graduate Coordinator Mohammad Reza SalimpourAbstract In simulation of a dynamic problem by computer dynamic equilibrium equations are solved by the finiteelement methods These methods estimate the solution on simple and small area of solution domain In the lasttwo decades many researchers attempted to avoid meshing These efforts lead to some unsuccessful methodssuch as mesh free Galerkin method and successful methods with simple and fixed grids such as extended finiteelement method and the finite cell method Improve in the response accuracy of finite element method indynamic problems is one of the main goals of these researches The smoothed finite element method and Edge base Smoothed finite element method are two verified finite element methods suggested to improve theaccuracy of results and reduce the computational cost So the wave propagation phenomena is the mostimportant dynamic problems in different engineering disciplines To simulate the wave propagation problem one of the most popular approximate methods is the nite element method FEM At high frequencies whenthe wavelengths become very small low order FEM h FEM may become inappropriate because the number ofthe elements that can estimate response accurately becomes too large and therefore the computational cost willbe very expensive Furthermore numerical inaccuracies arise at higher frequencies In this research the highfrequency wave propagation is simulated by the finite cell method In simulation of the discrete wavepropagation using high order finite element methods a new time integration method is proposed to remove thespurious oscillations before and after the wave tip To demonstrate the ability of the proposed method resultswere compared with analytical response In the next section using the new version of finite cell method wherethe B spline functions is used mass and stiffness matrices have been extracted and then time dependentequilibrium equations are solved using existing methods for solving differential equations To verify results responses are compared to the responses obtained from the spectral element method with very fine mesh andhigh degree of shape functions Key Words Wave propagation B spline and NURBS shape functions The finite cell method High order finiteelement method Implicit and explicit numerical integration Spurious oscillations Dispersion error Department of Mechanical Engineering Isfahan University of Technology Isfahan Iran

حسن نحوي، جمشيد پرويزيان

حميدرضا ميردامادي

بيژن برومند، محمود فرزين، مهرداد پورسينا، محمد مشايخي