Development and Design Optimization of High Fidelity Reduced Order Models for Dynamic Aeroelasticity Loads Analyses of Complex Airframes
Notice bibliographique
Résumé
Identification of aircraft critical loads envelope requires a lengthy and rigorous analysis procedure that includes simulating the aircraft at thousands of load cases identified in the certification requirements. Imposing a Global Finite Element Model (GFEM) in this process is computationally very expensive. Hence, Reduced Order Models (ROM) of airframes are commonly employed in the static and dynamic aeroelasticity analyses. ROMs must be simple enough to be analyzed thousands of times during the iterative aeroelastic simulation but sufficiently accurate to have their dynamic characteristics closely matching those of the GFEM within a frequency range of interest. Several Model Order Reduction (MOR) methodologies are available in the literature with the Stick Model (SM) being the preferred methodology adopted by the aerospace industry. A SM is a series of beam elements extending along the airframe elastic axis that offers an intuitive spatial representation of the airframe mass and stiffness distributions, a feature of paramount importance to the development engineers in the aerospace industry. However, due to several approximations and simplifications in the current development process, it is evidently found that SM's are not sufficiently appropriate for dynamic simulations. To overcome such limitation, this thesis presents two approaches for the development of high fidelity stick models. The first approach is based on a Hybrid Stick Model (HSM) representation in which the conventional SM is augmented by a set of structural matrices to account for inaccuracies that might be encountered in the modal performance of the base SM as compared to the GFEM. In the second approach, we solve a design optimization problem in which we optimize the stiffness parameters of the conventional SM to minimize errors in its modal pairs with reference to the GFEM. The final product of the optimization iii problem is an Optimized Stick Model (OSM) with dynamic characteristics that closely matching those of the GFEM within a specified frequency range of interest. Case studies are presented where the HSM and the OSM along with the conventional SM are employed in the dynamic aeroelasticity loads analyses of a Bombardier aircraft platform. The extracted aeroelastic loads are compared against those generated employing the aircraft GFEM. The dynamic characteristics of the ROMs are also assessed based on their modal characteristics using metrics of Modal Assurance Criteria (MAC) and Modal Participation Factors (MPF). Results obtained show that the developed HSM and OSM have superior dynamic characteristics compared to the conventional SM.
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Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,003 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,001 | 0,000 |
| Bibliométrie | 0,000 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».