应“飞行器复杂流动与控制学科创新引智基地”邀请，世界著名气动弹性专家、以色列理工学院Moti Karpel教授将于11月1日至11月3日就“Dynamic Response and Stability of Aero-Servo-Elastic Systems Using Increased-Order Modeling and Parametric Flutter Margins”主题开展三场讲座，欢迎相关专业师生参加交流。
11月1日 9:00-11:30 航空楼A706
An Increased-Order Modeling (IOM) approach to industrial aeroservoelastic analysis
11月2日 9:00-11:30 航空楼A706
A new parametric flutter margin (PFM) method for linear and nonlinear stability analysis of aeroservoelastic systems
11月3日 9:00-11:30 航空楼A706
The IOM approach in CFD-based aeroelastic response prediction
Moti Karpel is a Professor in the Faculty of Aerospace Engineering at the Technion in Haifa, Israel, holding the Sanford Kaplan Chair for Aerospace Engineering. He is also the owner of Karpel Dynamic Consulting Ltd. in Israel. He obtained B.Sc. degrees in Mechanical Engineering and in Aeronautical Engineering from the Technion in 1971, M.Sc. in Mechanical Engineering and Transportation from Tel Aviv University in 1975, and Ph.D. in Aerospace from Stanford University in 1980. In 1971 he joined the Engineering Division at Israel Aircraft Industries (IAI), where he was Head of the Flutter Group from 1975 to1977, when he went to Stanford. In 1980 he returned to IAI and
became Head of the Dynamics and Loads Department. In 1987 he went to NASA Langley Research Center for one year as an NRC Research Associate. He joined the Technion in 1988 where he teaches and conducts research in the areas of structural dynamics and aeroelasticity. Since joining the Technion he has held major research grants from NASA Langley, Lockheed Martin, US Air Force, General Motors, the Commission of the European Communities and the Government of Israel. He has fifty papers in archived professional journals. He has held enduring consulting assignments with EADS-CASA in Spain, EADS-MAS in Germany, SDI, ACX, and Cymer in the US,
the Nikkon Corporation in Japan and the Israel Aircraft Industries, Elbit, Rafel and others in Israel. He is the developer of several commercial codes such as the ASE and the GUST modules of the ZAERO software package, the DYNRESP code for aircraft dynamic loads with nonlinear elements and the STWTF code for flutter analysis of wind turbines. He has delivered international short courses and workshops on aeroelasticity at the Hampton Roads Section of AIAA in Virginia, Politecnico di Milano in Italy, Royal Melbourne Institute of Technology in Australia, DSO in Singapore, IST in Portugal, Lockheed-Martin in Texas, Embraer in Brazil and TU Delft in The Netherlands.
Aeroelasticity and structural dynamics, interaction with control systems, design methods.
Dynamic Response and Stability of Aero-Servo-Elastic Systems Using Increased-Order Modeling and Parametric Flutter Margins
I. An Increased-Order Modeling (IOM) approach to industrial aeroservoelastic analysis presented. The method is based on hybrid frequency-domain linear and time-marching nonlinear formulation. The method is applied to dynamic loads calculations using the Dynresp code developed in collaboration with Airbus Defence & Space. Numerical applications include dynamic loads due gust, maneuver and direct-force excitation, and due to self-excited vibrations caused by structural nonlinearity.
II. A new parametric flutter margin (PFM) method for linear and nonlinear stability analysis of aeroservoelastic systems is presented. The method is based on frequency response calculations with the system stabilized using a single parameter, which facilitates convenient response calculations with smooth response variations with respect to excitation frequency and air velocity. The frequency response functions are used for generating flutter and control-stability margins with respect to the added parameter. The linear method is expanded to efficiently deal with nonlinear elements in limit-cycle oscillations (LCO). The results demonstrate excellent agreement with those obtained using the NASTRAN and ZAERO common flutter codes, and the time-marching Dynresp code, with significant savings in computation time.
III. The IOM approach is applied in CFD-based aeroelastic response. The method is applied by integrating the ANSYN-Mechanical finite-elements, the ANSYS-Fluent CFD and the Dynresp ASE response codes. A robust method modal projection and load reconstruction between the structural and CFD grids is presented. Three options for calculating the buffet loads and the response levels on the elastic twin tails of a generic F18-like model are explored: (a) by extracting linearized unsteady generalized force coefficient from Fluent; (b) by a tightly coupled process where information between Fluent and Dynresp is exchanged at each time step; and (c) by a loosely coupled solution where the two codes are run sequentially.