The Influence of Residual Stress on the Design of Aircraft Primary Structure
Notice bibliographique
Résumé
Abstract Aggressive performance and weight objectives are driving aircraft manufacturers toward the use of advanced materials and structural concepts that may have inherent, process induced residual stresses in localized, but critical areas. Certification of these structures will require that the influence of these residual stresses be properly accounted for during design. One example of this circumstance is the unitization of lugs and fittings with primary spars and bulkheads. This is being done in order to reduce part count, which, in turn, reduces the necessity for large numbers of fasteners and the associated hole preparation/mating requirements. Such unitization can be achieved through the use of large forgings, which experience has shown may have significant residual stresses in localized areas, even after final machining. For man-rated flight vehicles, primary structural elements are typically designed based on damage tolerance concepts. This requires that fatigue crack growth analysis and testing be used for certification of the structure. Thus, for advanced design concepts based on unitized structure, the influence of residual stress on fatigue crack growth must be addressed. A substantial body of work has been developed over the past three decades by numerous researchers in the field of fracture mechanics with regard to residual stress. In what has become the standard approach to the problem, the residual stress field is used to estimate a residual stress intensity factor (SIF) using weight function or Green’s function techniques. The residual SIF is superimposed with the applied SIF due to service loading and the total is then used in an otherwise unmodified, LEFM-based fatigue crack growth analysis. In this paper, we describe current research directed toward the formal inclusion of residual stress effects in the design of aircraft primary structure. This effort has three focus areas. The first is the extraction of confounding residual stress effects during the characterization of the fundamental fatigue crack growth rate behavior of a critical aluminum alloy. The second is the quantification, both by analysis and experiment, of the location, spatial magnitude, and stress magnitude of the residual stress fields in a candidate forged/machined part. The third is the development of improved fatigue crack growth analysis methods that selectively account for the presence of residual stresses. Each of the three focus areas provides a critical ingredient to a proposed design analysis method in which components are analyzed using intrinsic (residual stress free) material data, with residual stresses then explicitly introduced only in those areas where they are known to exist. The discussion includes the results of a trade study on a wing spar showing potential optimization, both in terms of weight savings in over-designed areas, and service life/damage tolerance enhancement in under-designed areas.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
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 | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| 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 ».