Aircraft primary structure elements are subjected during their operational life to fatigue variable loads that can damage parts of the structure and reduce the primary structure efficiency. Fatigue and damage tolerance analysis aims to determine the most critical zones of the structure, obtain accurate results in terms of time before failure for these zones and determine inspection thresholds and intervals for maintenance tasks. Airbus fatigue and damage tolerance analysis approach for legacy primary metal structure is considered for the project. Within Airbus Single Aisle A320 fatigue and damage tolerance engineering office, the new software “Python Supermoulinette” is developed for managing fatigue and damage tolerance data, analyses execution, results post-processing and additional analysis tools. The project is developed in accordance with Airbus calculation procedures and office usual work organisation. Load and stress variability in time are analysed thanks to spectrum representation of aircraft mission phases conditions and possible perturbations. Load and stress histories are simplified to equivalent stress values, representing a level of cumulative damage and that can be directly related to expected service life. Airbus projects concerned by the development of the new software and to which the software is adapted are forward fuselage and central wing box of all versions of A318, A319, A320 and A321, including recent Sharklet and future NEO evolutions. The new software is developed with Python language and integrated on a fully-Linux calculation process. It is developed in order to substitute an equivalent Excel tool and improve its performances in terms of user-friendliness and execution time. Execution test demonstrate a large improvement of performances and an equivalent accuracy level in results obtained. The software is likely to become the official tool for future fatigue and damage tolerance analyses in the concerned department.
I componenti della struttura primaria dei velivoli sono soggetti nel corso della loro vita operativa a carichi di fatica variabili, i quali possono danneggiare parti della struttura e ridurne l’efficienza. L’analisi di fatica e tolleranza al danno si propone di determinare le zone più critiche della struttura, ottenere per queste zone risultati più accurati in termini di vita a fatica e determinare di conseguenza soglie e intervalli di ispezione. Il progetto di tesi si occupa dell’analisi di fatica e tolleranza al danno condotta secondo i metodi elaborati per le strutture metalliche dei progetti “legacy” di Airbus, escluso quindi il programma A350. Il nuovo software “Python Superrmoulinette”, incaricato della gestione di dati e esecuzione di analisi di fatica e tolleranza al danno, viene sviluppato in cooperazione con il dipartimento di analisi di fatica del programma A320. Il progetto è sviluppato in accordo con le procedure di calcolo Airbus e con l’organizzazione interna del dipartimento. L’analisi di carichi e sforzi è condotta tramite l’utilizzo di “spettri di carico” e semplificata grazie al calcolo di sforzi equivalenti che rappresentano un livello cumulativo di danneggiamento direttamente relazionabile con la durata di vita a fatica. I programmi Airbus coinvolti e analizzati nel corso del progetto includono A318, A319, A320 e A321, sia nelle loro versioni attuali, sia nelle nuove versioni denominate “Sharklet” e “NEO”. I metodi sono adattati in particolare alla porzione avanzata della fusoliera e al cassone alare centrale. Il nuovo software è basato su una programmazione con linguaggio Python e viene integrato in un contesto di calcolo interamente supportato da un sistema operativo Linux. Esso viene sviluppato in sostituzione ad un altro software precedentemente utilizzato, basato su una coordinazione di fogli Excel e macro VBA. Il nuovo software mostra potenzialità notevolmente superiori a quelle del suo predecessore, ed anche per questo sarà con ogni probabilità adottato come software ufficiale per le analisi di fatica e tolleranza al danno nei mesi a seguire.
Development of a Python software managing fatigue and damage tolerance analyses for Airbus A320 family aircraft
PANOZZO, SILVIO
2012/2013
Abstract
Aircraft primary structure elements are subjected during their operational life to fatigue variable loads that can damage parts of the structure and reduce the primary structure efficiency. Fatigue and damage tolerance analysis aims to determine the most critical zones of the structure, obtain accurate results in terms of time before failure for these zones and determine inspection thresholds and intervals for maintenance tasks. Airbus fatigue and damage tolerance analysis approach for legacy primary metal structure is considered for the project. Within Airbus Single Aisle A320 fatigue and damage tolerance engineering office, the new software “Python Supermoulinette” is developed for managing fatigue and damage tolerance data, analyses execution, results post-processing and additional analysis tools. The project is developed in accordance with Airbus calculation procedures and office usual work organisation. Load and stress variability in time are analysed thanks to spectrum representation of aircraft mission phases conditions and possible perturbations. Load and stress histories are simplified to equivalent stress values, representing a level of cumulative damage and that can be directly related to expected service life. Airbus projects concerned by the development of the new software and to which the software is adapted are forward fuselage and central wing box of all versions of A318, A319, A320 and A321, including recent Sharklet and future NEO evolutions. The new software is developed with Python language and integrated on a fully-Linux calculation process. It is developed in order to substitute an equivalent Excel tool and improve its performances in terms of user-friendliness and execution time. Execution test demonstrate a large improvement of performances and an equivalent accuracy level in results obtained. The software is likely to become the official tool for future fatigue and damage tolerance analyses in the concerned department.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/82965