| Autor: |
Luis Anguita, Carlos Maderuelo, Eyal Presente, Boris Moulin, Hector Climent, Moti Karpel |
| Rok vydání: |
2008 |
| Předmět: |
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| Zdroj: |
49th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference 16th AIAA/ASME/AHS Adaptive Structures Conference 10t. |
| DOI: |
10.2514/6.2008-1994 |
| Popis: |
A process for calculating dynamic gust loads for structural design of transport aircraft with significant non-linear control-system effects is presented. The process is based on combinations of timeand frequency domain formulations of the equations of motion that facilitate the inclusion of nonlinear control elements. The frequency-domain approach is used for massive loads calculations using Fast Fourier Transform techniques. Special measures are employed for repeated analyses with many weight distributions and various gust excitations. Selected cases are repeated for the evaluation of the nonlinear control effects using time-domain, state-space linear models of the aeroelastic system combined with nonlinear control equations. The resulting time histories of the structural and control response in modal coordinates of the two approaches are then used for the calculation of structural loads using mode-displacement or summation-of-force techniques. The generation of aeroservoelastic time-domain models requires the approximation of the unsteady aerodynamic force coefficient matrices in the time domain. To avoid approximation errors associated with the gust force coefficients, the excitation forces are defined by a sequence of Fourier and Inverse-Fourier transforms. Convergence studies demonstrate the accuracy and efficiency of the various computation options with respect to the number of structural modes taken into account. The loads computation processes are demonstrated with discrete gust loads on the A400M military transport currently under development. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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