Flutter prediction of a swept back plate using experimental model parameters

Pankaj, AC and Shivaprasad, MV and Shantini, G and Chandra, N and Nandan , A M and Manjuprasad, M (2011) Flutter prediction of a swept back plate using experimental model parameters. In: Symposium on Applied Aerodynamics and Design of Aerospace Vehicle (SAROD 2011), November 16-18, 2011, Bangalore, India.

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The model parameters such as eigen values & vectors play a very important role in formulation of unsteady/steady aerodynamics and the subsequent derived aeroelastic results like flutter speeds etc. Slight variations in these values have noticeable changes in flutter characteristics. In the procedure proposed in this paper, the eigen values and mass normalized eigen vectors replace the values obtained through a normal modes solution of the equivalent finite element model of a swept back plate by invoking a Direct Matrix Abstraction Program (DMAP) sequence in the flutter solution of NASTRAN using statements available in DMAP. In case of use of ZAERO software for flutter computations, the eigen values and eigen vectors in the normal modes results file, obtained from NASTRAN is replaced directly with the experimentally obtained values. The flutter solution of the structure continues with the replaced eigen values and vectors. The flutter results obtained by using the FE model of a swept back plate with known geometric and material properties has been compared with the developed program sequence using experimental modal parameters. The studies have been done for both the cases, using unsteady doublet lattice aerodynamics in case of NASTRAN and ZONA6 aerodynamics for ZAERO software. Thus the errors, that result in a finite element normal modes analysis, caused due to improper representation of the boundary conditions, material properties and damping has been eliminated and the program sequence helps in a realistic prediction of flutter characteristics of the structure with the only requirement of the geometric configuration of the structure and need no material property, mass or stiffness related parameters for the finite element modeling of the structure.

Item Type: Conference or Workshop Item (Paper)
Uncontrolled Keywords: Flutter, Finite Element Method, DMAP, Modal Parameters
Subjects: AERONAUTICS > Aerodynamics
Depositing User: Smt Bhagya Rekha KA
Date Deposited: 24 Jan 2012 04:27
Last Modified: 24 Jan 2012 04:27
URI: http://nal-ir.nal.res.in/id/eprint/10270

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