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Dissertations / Theses on the topic 'Aircraft reliability'
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1
Yang, Ju-Sung. "System reliability optimization of aircraft wings." Diss., Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/54818.
Full textAbstract:
System reliability based design of aircraft wings is studied. A wing of a light commuter aircraft designed according to the FAA regulations is compared with one designed by system reliability optimization. Both the level III, and the advanced first order, second moment (AFOSM) method are employed to evaluate the probability of failure of each failure element of the system representing the wing. In the level III method the statistical correlation between failure modes is neglected. The AFOSM method allows to evaluate the sensitivity derivatives of the system safety index analytically. Furthermore, it accounts for the statistical correlation between failure modes. The results demonstrate the potential of stochastic optimization, and the importance of accounting for the statistical correlation between failure modes. Finally, it is shown that the problem associated with discontinuity of sensitivity derivatives, encountered when using second order Ditlevsen upper bounds to estimate the system failure probability, is circumvented if a penalty function method is used for optimization.Ph. D.
2
Rambalakos, Andreas. "Monte Carlo simulation methodology for the reliability of aircraft structures reliability of aircraft structures under damage tolerance requirements." Saarbrücken VDM Verlag Dr. Müller, 2006. http://d-nb.info/988567741/04.
Full text
3
Cook, Lawrence. "Visual inspection reliability for composite aircraft structures." Thesis, Cranfield University, 2009. http://dspace.lib.cranfield.ac.uk/handle/1826/6834.
Full textAbstract:
This thesis presents a study of the effects of surface colour, surface finish and dent
shape on the visual inspection reliability of 3D surface indentations common in shape
to those produced by impact damage to carbon fibre reinforced epoxy laminates.
Falling weight (2.5kg) apparatus was used to produce impact damage to non-painted,
non-mesh Hexcel AS4/ 8552 carbon fibre reinforced plastic (CFRP) laminates and
painted AS4/ 8552 laminates containing bronze mesh and glass fabric lightning strike
protection layers. Ø20 mm and Ø87 mm hemispherical tip impacts to painted 17ply
and 33ply laminates at varying energy levels typically produced circular shaped,
smoothly contoured, rounded sectional profiles with an absence of surface breaking
cracks.
Sectional profiles through coordinate measuring (CMM) data of the impact dents
were described using a set of geometric variables. Identifying relationships between
impact energy and the geometric variables allowed the typical sectional profile
through impact damage dents from Ø20 mm and Ø87 mm hemispherical tips on 17ply
and 33ply painted CFRP laminates to be calculated for energies between 5J to 80J.
Calculated sectional profiles typical of impact damage dents to CFRP laminates were
reconstructed as simple revolved shapes using 3D computer aided design (CAD)
models. The 3D CAD models were computer numerical control (CNC) machined into
3mm Plexiglas panels to produce facsimiles of hemispherical impact damage dents on
CFRP laminates.
Facsimile specimen sets of sixteen 600 mm x 600 mm panels were produced in gloss
and matt grey, white and blue finishes. Each set contained the same 32 different sized
machined dents representing Ø20 mm and Ø87 mm hemispherical tip impact damage
to 17ply & 33ply painted CFRP laminate. Each facsimile specimen set was combined
with similarly finished unflawed (dent free) panels. 64 panels in each colour/ finish
were presented for 5 seconds in a randomised order to a minimum of 15 novice
participants in a visual inspection task lasting approximately 25 minutes.
II
A set of corresponding visual inspection experiments were performed in which
physical specimens were replaced by digitally projected actual size photorealistic
images of the machining CAD data. Comparisons between the results of the physical
and virtual specimen trials revealed differences in detectability for similarly sized
dents.
The detection results obtained from visual inspection of physical specimens
demonstrated that the detectability of dents similar to those caused by higher (>40J)
energy impacts from a Ø87 mm hemispherical tip was less than that of the dents
caused by lower energy (<20J) impacts from Ø20 mm tips. However, larger
subsurface delamination area was demonstrated by the higher energy Ø87 mm
impacts than lower energy Ø20 mm impacts on 150 mm x 100 mm coupons of the
same thickness laminate. The results of these experiments imply that detectability of
dents caused by larger diameter objects at higher energies cannot be assumed to be
greater than that of lower energy impacts from smaller diameter objects.
The detection results demonstrate that detectability by visual inspection cannot be
assumed the same for an impact dent on different surface colours and finishes. In
general terms, the highest numbers of dents returning >90% detection were observed
on grey specimens and the highest number of dents returning 0% detection were
observed on matt blue specimens. The difference in detection rates for similarly sized
dents on a gloss and matt finish was least on grey coloured specimens and greatest on
blue coloured specimens.
4
Bineid, Mansour. "Aircraft systems design methodology and dispatch reliability prediction." Thesis, Cranfield University, 2005. http://dspace.lib.cranfield.ac.uk/handle/1826/5415.
Full textAbstract:
Aircraft despatch reliability was the main subject of this research in the wider content of aircraft reliability. The factors effecting dispatch reliability, aircraft delay, causes of aircraft delays, and aircraft delay costs and magnitudes were examined. Delay cost elements and aircraft delay scenarios were also studied. It concluded that aircraft dispatch reliability is affected by technical and non-technical factors, and that the former are under the designer's control. It showed that the costs of aircraft delays are very significant and must be reduced. Cont/d.
5
Vaziry-Zanjany, Mohammad Ali. "Aircraft conceptual design modelling incorporating reliability and maintainability predictions." Thesis, Cranfield University, 1996. http://dspace.lib.cranfield.ac.uk/handle/1826/3437.
Full textAbstract:
A computer assisted conceptual aircraft design program has been developed (CACAD). It has an optimisation capability, with extensive break-down in maintenance costs. CACAD's aim is to optimise the size, and configurations of turbofan-powered transport aircraft. A methodology was developed to enhance the reliability of current aircraft systems, and was applied to avionics systems. R&M models of thermal management were developed and linked with avionics failure rate and its maintenance cost prediction methods. The impact of the environmental control system, and engine-provided bleed flow was also modelled and incorporated into CACAD. The program showed the ARINC 600 & 408A flow rates to the avionics bay, and to the deck instruments may both profitably be increased by 50%. This keeps the direct operating cost (DOC) increase at bay for long-range passenger aircraft, and offers a reduction of up to 1% in DOC for the short to medium range passenger aircraft. A methodology was developed to model all aspects of future high risk technologies, with special consideration given to reliability, maintainability, and development cost (R, M&D) predictions as applied to variable camber wings (VCW). Many aspects of VCW were modelled. These included different types of drag saving due to chord- wise, as well as span-wise camber variation. Models were also derived for mass, maintenance cost, and extra development cost increments for wing trailing edge devices, flight control, and hydraulic systems. On incorporation into CACAD, a reduction in DOC of up to 3.5% was predicted. The VCW technology were evaluated for DOC improvements, against a number of existing, future, and derivative aircraft, under different sensitivity conditions. R, M&D predictions were shown to be decisive in addressing the feasibility of a new technology. The R&M predictions of the whole study shows that, long range, low to medium capacity derivative transport aircraft are most appropriate for the VCW technology, and the short to medium range, low to medium capacity aircraft are most suitable for reliability enhancement projects of aircraft advanced systems.
6
Vaziry-Zanjany, Mohammad Ali (F). "Aircraft conceptual design modelling incorporating reliability and maintainability predictions." Thesis, Cranfield University, 1996. http://hdl.handle.net/1826/3437.
Full textAbstract:
A computer assisted conceptual aircraft design program has been developed
(CACAD). It has an optimisation capability, with extensive break-down in
maintenance costs. CACAD's aim is to optimise the size, and configurations of
turbofan-powered transport aircraft.
A methodology was developed to enhance the reliability of current aircraft systems,
and was applied to avionics systems. R&M models of thermal management were
developed and linked with avionics failure rate and its maintenance cost prediction
methods. The impact of the environmental control system, and engine-provided bleed
flow was also modelled and incorporated into CACAD. The program showed the
ARINC 600 & 408A flow rates to the avionics bay, and to the deck instruments may
both profitably be increased by 50%. This keeps the direct operating cost (DOC)
increase at bay for long-range passenger aircraft, and offers a reduction of up to 1% in
DOC for the short to medium range passenger aircraft.
A methodology was developed to model all aspects of future high risk technologies,
with special consideration given to reliability, maintainability, and development cost
(R, M&D) predictions as applied to variable camber wings (VCW). Many aspects of
VCW were modelled. These included different types of drag saving due to chord-
wise, as well as span-wise camber variation. Models were also derived for mass,
maintenance cost, and extra development cost increments for wing trailing edge
devices, flight control, and hydraulic systems. On incorporation into CACAD, a
reduction in DOC of up to 3.5% was predicted. The VCW technology were evaluated
for DOC improvements, against a number of existing, future, and derivative aircraft,
under different sensitivity conditions. R, M&D predictions were shown to be decisive
in addressing the feasibility of a new technology.
The R&M predictions of the whole study shows that, long range, low to medium
capacity derivative transport aircraft are most appropriate for the VCW technology, and the short to medium range, low to medium capacity aircraft are most suitable for
reliability enhancement projects of aircraft advanced systems.
7
Chu, Liu. "Reliability and optimization, application to safety of aircraft structures." Thesis, Rouen, INSA, 2016. http://www.theses.fr/2016ISAM0008/document.
Full textAbstract:
Les chercheurs dans le domaine de la conception aérodynamique et de la fabrication des avions ont fait beaucoup d'effort pour améliorer les performances des ailes par des techniques d'optimisation. Le développement de la mécanique des fluides numérique a permis de réduire les dépenses en soufflerie tout en fournissant des résultats convaincants pour simuler des situations compliquées des aéronefs. Dans cette thèse, il a été choisi une partie spéciale et importante de l'avion, à savoir, la structure de l'aile. L'optimisation basée sur la fiabilité est une méthode plus appropriée pour les structures sous incertitudes. Il se bat pour obtenir le meilleur compromis entre le coût et la sécurité tout en tenant compte des incertitudes du système en intégrant des mesures de fiabilité au sein de l'optimisation. Malgré les avantages de l'optimisation de la fiabilité en fonction, son application à un problème d'ingénierie pratique est encore assez difficile. Dans notre travail, l'analyse de l'incertitude dans la simulation numérique est introduite et exprimée par la théorie des probabilités. La simulation de Monte Carlo comme une méthode efficace pour propager les incertitudes dans le modèle d'éléments finis de la structure est ici appliquée pour simuler les situations compliquées qui peuvent se produire. Pour améliorer l'efficacité de la simulation Monte Carlo dans le processus d'échantillonnage, la méthode de l'Hypercube Latin est effectuée. Cependant, l'énorme base de données de l'échantillonnage rend difficile le fait de fournir une évaluation explicite de la fiabilité. L'expansion polynôme du chaos est présentée et discutée. Le modèle de Kriging comme un modèle de substitution joue un rôle important dans l'analyse de la fiabilité. Les méthodes traditionnelles d'optimisation ont des inconvénients à cause du temps de calcul trop long ou de tomber dans un minimum local causant une convergence prématurée. Le recuit simulé est une méthode heuristique basée sur une recherche locale, les Algorithmes Génétiques puisent leur inspiration dans les principes et les mécanismes de la sélection naturelle, qui nous rendent capables d'échapper aux pièges des optimums locaux. Dans l'optimisation de la conception de base de la fiabilité, ces deux méthodes ont été mises en place comme procédure d'optimisation. La boucle de l'analyse de fiabilité est testée sur le modèle de substitutionTremendous struggles of researchers in the field of aerodynamic design and aircraft production were made to improve wing airfoil by optimization techniques. The development of computational fluid dynamic (CFD) in computer simulation cuts the expense of aerodynamic experiment while provides convincing results to simulate complicated situation of aircraft. In our work, we chose a special and important part of aircraft, namely, the structure of wing.Reliability based optimization is one of the most appropriate methods for structural design under uncertainties. It struggles to seek for the best compromise between cost and safety while considering system uncertainties by incorporating reliability measures within the optimization. Despite the advantages of reliability based optimization, its application to practical engineering problem is still quite challenging. In our work, uncertainty analysis in numerical simulation is introduced and expressed by probability theory. Monte Carlo simulation as an effective method to propagate the uncertainties in the finite element model of structure is applied to simulate the complicate situations that may occur. To improve efficiency of Monte Carlo simulation in sampling process, Latin Hypercube sampling is performed. However, the huge database of sampling is difficult to provide explicit evaluation of reliability. Polynomial chaos expansion is presented and discussed. Kriging model as a surrogate model play an important role in the reliability analysis.Traditional methods of optimization have disadvantages in unacceptable time-complexity or natural drawbacks of premature convergence because of finding the nearest local optima of low quality. Simulated Annealing is a local search-based heuristic, Genetic Algorithm draws inspiration from the principles and mechanisms of natural selection, that makes us capable of escaping from being trapped into a local optimum. In reliability based design optimization, these two methods were performed as the procedure of optimization. The loop of reliability analysis is running in surrogate model
8
Alkhatib, K. Y. "Analytical redundancy scheme for improving reliability of automatic flight control systems for aircraft." Thesis, Loughborough University, 1985. https://dspace.lboro.ac.uk/2134/31989.
Full textAbstract:
Any redundancy scheme in aircraft control systems is usually considered separately from the control algorithms involved. All feedback control systems are usually designed under the assumption that their sensors will not fail. When the integrity requirements demand it, then a redundancy scheme must be designed to provide any required measurements with only extremely short interruptions to normal service being caused by failures of individual sensors.
9
King, Merrill F. "A reliability centered maintenance analysis of aircraft control bearings used in the Navy's S-3 aircraft." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1997. http://handle.dtic.mil/100.2/ADA342292.
Full textAbstract:
Thesis (M.S. in Management) Naval Postgraduate School, December 1997."December 1997." Thesis advisor(s): Keebom Kang, Donald R. Eaton. Includes bibliographical references (p. 73-74). Also available online.
10
Dermentzoudis, Marinos. "Establishment of models and data tracking for small UAV reliability." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Jun%5FDermentzoudis.pdf.
Full textAbstract:
Thesis (M.S. in Operations Research and M.S. in Systems Engineering)--Naval Postgraduate School, June 2004.Thesis advisor(s): David Olwell. Includes bibliographical references (p. 217-224). Also available online.
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Baldwin, Richard P. "Aircraft engine reliability analysis using lower confidence limit estimate procedures." Thesis, Monterey, California. Naval Postgraduate School, 1992. http://hdl.handle.net/10945/23522.
Full textAbstract:
Approved for public release; distribution is unlimitedIn this thesis, a spreadsheet model was developed to compute the lower confidence limit (LCL) for the reliability of a complex weapon system using a personal computer. the LCL is an estimate of the lowest reliability a system is expected to have at a given point in time with a given level of confidence. The reliability model is based on a Weibull distribution for the system component failure times. the reliability LCL procedures has been extensively validated and determined to be quite accurate when the expected number of failures is at least 10. This model is capable of supporting :LCL decisions in support of the Component Improvement Program or new weapon system procurement where reliability growth analysis is used as a decision support tool. This procedure also provides program managers and engineers with a method to perform LCL analysis and thereby reduce their dependence on contractor supplied reliability data.
12
Tiassou, Kossi. "Aircraft operational reliability - A Model-based approach and case studies." Phd thesis, INSA de Toulouse, 2013. http://tel.archives-ouvertes.fr/tel-00807442.
Full textAbstract:
Lors de la conception des avions, il est courant que les constructeurs évaluent la sûreté de fonctionnement en utilisant des modèles stochastiques, mais l'évaluation de la fiabilité opérationnelle à l'aide de modèles en ligne, pendant la réalisation des missions, reste rarement effectuée. Souvent, l'évaluation stochastique concerne la sécurité des avions. Cette thèse porte sur la modélisation de la fiabilité opérationnelle des avions, pour aider à la planification des activités de maintenance et des missions, ainsi qu'à la bonne réalisation de ces dernières. Nous avons développé une approche de modélisation, basée sur un méta-modèle qui sert de base i) de structuration des informations nécessaires à l'évaluation de la fiabilité opérationnelle d'un avion et ii) pour la construction de modèles stochastiques pouvant être mis à jour dynamiquement. La mise à jour concerne l'état courant des systèmes avion, un profil de mission et les moyens de maintenance disponibles dans les diverses escales incluses dans le profil de la mission. L'objectif est de permettre l'évaluation de la fiabilité opérationnelle en ligne. Deux cas d'études, basés sur des sous-systèmes avion, sont considérés à titre d'illustration. Nous présentons des exemples de résultats qui montrent le rôle important de l'évaluation de la fiabilité opérationnelle pendant une mission d'avion.
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Tiassou, Kossi Blewoussi. "Aircraft operational reliability : A model-based approach and case studies." Thesis, Toulouse, INSA, 2013. http://www.theses.fr/2013ISAT0012/document.
Full textAbstract:
Lors de la conception des avions, il est courant que les constructeurs évaluent la sûreté de fonctionnement en utilisant des modèles stochastiques, mais l'évaluation de la fiabilité opérationnelle à l’aide de modèles en ligne, pendant la réalisation des missions, reste rarement effectuée. Souvent, l'évaluation stochastique concerne la sécurité des avions. Cette thèse porte sur la modélisation de la fiabilité opérationnelle des avions, pour aider à la planification des activités de maintenance et des missions, ainsi qu’à la bonne réalisation de ces dernières. Nous avons développé une approche de modélisation, basée sur un méta-modèle qui sert de base i) de structuration des informations nécessaires à l’évaluation de la fiabilité opérationnelle d’un avion et ii) pour la construction de modèles stochastiques pouvant être mis à jour dynamiquement. La mise à jour concerne l'état courant des systèmes avion, un profil de mission et les moyens de maintenance disponibles dans les diverses escales incluses dans le profil de la mission. L'objectif est de permettre l'évaluation de la fiabilité opérationnelle en ligne. Deux cas d’études, basés sur des sous-systèmes avion, sont considérés à titre d'illustration. Nous présentons des exemples de résultats qui montrent le rôle important de l’évaluation de la fiabilité opérationnelle pendant une mission d’avionDependability assessment, by system manufacturer, during aircraft design, based on stochastic modeling, is of common practice, but model based operational dependability assessment online, during missions' achievement, is seldom done. Usually, the stochastic assessment addresses aircraft safety.This thesis addresses aircraft operational dependability modeling to support mission and maintenance planning, as well as the achievement of the missions. We develop a modeling approach, based on a meta-model that is used as a basis i) to structure the information needed to assess aircraft operational reliability and ii) to build a stochastic model that can be updated dynamically. The update concerns the current state of the aircraft system, a mission profile and the maintenance facilities available at the flight stop locations involved in the mission. The aim is to enable operational reliability assessment online. Two case studies, based on aircraft subsystems, are considered for illustration. We present examples of evaluation results that show the valuable role of operational dependability assessment during aircraft mission
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Wang, Xiaoyang. "Aircraft fuel system prognostics and health management." Thesis, Cranfield University, 2012. http://dspace.lib.cranfield.ac.uk/handle/1826/7214.
Full textAbstract:
This thesis contains the specific description of Group Design Project (GDP) and
Individual Research Project (IRP) that are undertaken by the author and form
part of the degree of Master of Science.
The target of GDP is to develop a novel and unique commercial flying wing
aircraft titled FW-11. FW-11 is a three-year collaborative civil aircraft project
between Aviation Industry Corporation of China (AVIC) and Cranfield University.
According to the market analysis result conducted by the author, 250 seats
capacity and 7500 nautical miles were chosen as the design targets.
The IRP is the further study of GDP, which is to enhance the competitive
capability by deploying prognostics and health management (PHM) technology
to the fuel system of FW-11. As a novel and brand-new technology, PHM
enables the real-time transformation of system status data into alert and
maintenance information during all ground or flight operating phases to improve
the aircraft reliability and operating costs. Aircraft fuel system has a great
impact on flight safety. Therefore, the development of fuel system PHM concept
is necessary.
This thesis began with an investigation of PHM, then a safety and reliability
analysis of fuel system was conducted by using FHA, FMEA and FTA.
According to these analyses, fuel temperature diagnosis and prognosis were
chosen as a case study to improve the reliability and safety of FW-11. The PHM
architecture of fuel temperature had been established. A fuel temperature
prediction model was also introduced in this thesis.
15
Alshammari, Younes. "The effects of adverse climatic conditions on aircraft reliability and maintenance." Thesis, University of Leeds, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.582742.
Full textAbstract:
This thesis describes the effects of adverse climatic conditions (sand-dust and high temperature) on aircraft reliability and maintenance. An important and necessary part of the research was conducting field work in aircraft maintenance organisations in Kuwait in order to identify the problems and associated difficulties from the adverse climatic conditions on aircraft systems and aircraft maintenance. Also collected were data and aircraft samples so that they could be analysed to construct models which can be implemented in aircraft maintenance. This research has shown that there are three main systems affected by sand-dust, namely engine, avionics and air conditioning. Engine system experienced significant impact by sand-dust. The PM1Q concentration of sand-dust was found to be the dominant particle size in all three aircraft systems. The PM10 concentration and meteorological parameters were found to be significantly correlated. Two prototype models were constructed, namely Model 1 and Model 2. Forecasts of PM1Q concentration value is generated from meteorological parameters in Model 1. The percentage of deterioration of engine HPT blade from sand-dust contamination is predicted from engine flight data, PM10 concentration and meteorological parameters by Model 2. Both models were tested using historic data and found to accurately predict the PM10 concentration and deterioration of engine HPT blade respectively. In summary, this research provides a novel approach to improve aircraft reliability and maintenance in. arid and semi-arid regions Where sand-dust is dominant, by the implementation of the two prototype models.
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Muniraj, Devaprakash. "On the Security and Reliability of Fixed-Wing Unmanned Aircraft Systems." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/102702.
Full textAbstract:
The focus of this dissertation is on developing novel methods and extending existing ones to improve the security and reliability of fixed-wing unmanned aircraft systems (UAS). Specifically, we focus on three strands of work: i) designing UAS controllers with performance guarantees using the robust control framework, ii) developing tools for detection and mitigation of physical-layer security threats in UAS, and iii) extending tools from compositional verification to design and verify complex systems such as UAS.
Under the first category, we use the robust H-infinity control approach to design a linear parameter-varying (LPV) path-following controller for a fixed-wing UAS that enables the aircraft to follow any arbitrary planar curvature-bounded path under significant environmental disturbances. Three other typical path-following controllers, namely, a linear time-invariant H-infinity controller, a nonlinear rate-tracking controller, and a PID controller, are also designed. We study the relative merits and limitations of each approach and demonstrate through extensive simulations and flight tests that the LPV controller has the most consistent position tracking performance for a wide array of geometric paths. Next, convex synthesis conditions are developed for control of distributed systems with uncertain initial conditions, whereby independent norm constraints are placed on the disturbance input and the uncertain initial state. Using this approach, we design a distributed controller for a network of three fixed-wing UAS and demonstrate the improvement in the transient response of the network when switching between different trajectories.
Pertaining to the second strand of this dissertation, we develop tools for detection and mitigation of security threats to the sensors and actuators of UAS. First, a probabilistic framework that employs tools from statistical analysis to detect sensor attacks on UAS is proposed. By incorporating knowledge about the physical system and using a Bayesian network, the proposed approach minimizes the false alarm rates, which is a major challenge for UAS that operate in dynamic and uncertain environments. Next, the security vulnerabilities of existing UAS actuators are identified and three different methods of differing complexity and effectiveness are proposed to detect and mitigate the security threats. While two of these methods involve developing algorithms and do not require any hardware modification, the third method entails hardware modifications to the actuators to make them resilient to malicious attacks. The three methods are compared in terms of different attributes such as computational demand and detection latency.
As for the third strand of this dissertation, tools from formal methods such as compositional verification are used to design an unmanned multi-aircraft system that is deployed in a geofencing application, where the design objective is to guarantee a critical global system property. Verifying such a property for the multi-aircraft system using monolithic (system-level) verification techniques is a challenging task due to the complexity of the components and the interactions among them. To overcome these challenges, we design the components of the multi-aircraft system to have a modular architecture, thereby enabling the use of component-based reasoning to simplify the task of verifying the global system property. For component properties that can be formally verified, we employ results from Euclidean geometry and formal methods to prove those properties. For properties that are difficult to be formally verified, we rely on Monte Carlo simulations. We demonstrate how compositional reasoning is effective in reducing the use of simulations/tests needed in the verification process, thereby increasing the reliability of the unmanned multi-aircraft system.Doctor of Philosophy
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Gates, Melinda M. "The Effect of Icing on the Dispatch Reliability of Small Aircraft." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/35946.
Full textAbstract:
In 2000, the National Aeronautics and Space Administration (NASA) initiated a program to promote the use of small aircraft as an additional option for national public transportation. The Small Aircraft Transportation System (SATS) asserted the idea of everyday individuals piloting themselves on trips, within a specified distance range, using a small (4 person), piston powered, un-pressurized aircraft and small airports in close proximity to their origin and destination.
This thesis investigates how one weather phenomenon, in-flight icing, affects the dispatch reliability of this transportation system. Specifically, this research presumes that a route is considered a "no-go" for low time pilots in a small, piston powered aircraft if any icing conditions are forecast along the route at the altitude of the flight during the time the traveler desires to make the trip.
This thesis evaluates direct flights between Cleveland and Boston; Boston and Washington, D.C.; and Washington, D.C. and Cleveland during the months of November through May for the years 2001 to 2003 at maximum cruising altitudes of 6,000 feet, 8,000 feet, 10,000 feet, and 12,000 feet above mean sea level (MSL). It was found that the overall probability of a "no-go" for all three flight paths at the normal cruising altitude of 12,000 feet is 56.8%. When the cruising altitude is reduced to 10,000 feet, 8,000 feet, and 6,000 feet the probability of a "no-go" for all three flight paths reduces to 54.6%, 48.5%, and 43.7% respectively.
Master of Science
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Nam, G. W. "Development of safety and reliability prediction methodology for aircraft systems with common-cause failures." Thesis, Cranfield University, 1996. http://dspace.lib.cranfield.ac.uk/handle/1826/11287.
Full textAbstract:
A methodology has been developed for predicting aircraft safety and reliability incorporating both C.C.F.s(Common-Cause Failures), and phased missions. Failure behaviour of an aircraft, or its systems due to both independent failures and C.C.F.s are modelled by the Markov process, and simulated using Monte Carlo method with the robust variance reduction techniques. Prediction of safety and reliability is made through discrete-event simulation of aircraft operations. Validation was made by comparing the predicted safety and reliability results of B767 ETOPS aircraft propulsion system, using the developed methodology, to those obtained from the analysis of real operation data. The credibility and the accuracy of the developed methodology are shown through the comparison of results. A case study was conducted for investigating the safety and reliability of the propulsion system of two-, three- and four-engined aircraft using the developed methodology. The case study produced valuable results concerning the safety of ETOPS flight, which were not previously known. These results were able to be used for further trade studies of aircraft design to decide the number of engines, and also for establishing new regulations for ETOPS flights.
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Ivanovitch, Marianna. "Design of virtual aircraft multipurpose platform." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amslaurea.unibo.it/5295/.
Full textAbstract:
This report elaborates on the master degree thesis developed by the candidate within the company Superjet International.
The performed activity focuses on the study and design of VAMP (Virtual Aircraft Multipurpose Platform).
VAMP is a new interactive platform, not necessarily limited to the Aeronautical sector, aimed to analyse technical failures, identify risk and recommend the most appropriate corrective actions for maintenance cost reduction, taking into account reliability, availability, maintainability and safety.
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Chen, Qing. "Reliability-based structural design: a case of aircraft floor grid layout optimization." Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/39630.
Full textAbstract:
In this thesis, several Reliability-based Design Optimization (RBDO) methods and algorithms for airplane floor grid layout optimization are proposed. A general RBDO process is proposed and validated by an example. Copula as a mathematical method to model random variable correlations is introduced to discover the correlations between random variables and to be applied in producing correlated data samples for Monte Carlo simulations. Based on Hasofer-Lind (HL) method, a correlated HL method is proposed to evaluate a reliability index under correlation. As an alternative method for computing a reliability index, the reliability index is interpreted as an optimization problem and two nonlinear programming algorithms are introduced to evaluate reliability index. To evaluate the reliability index by Monte Carlo simulation in a time efficient way, a kriging-based surrogate model is proposed and compared to the original model in terms of computing time. Since in RBDO optimization models the reliability constraint obtained by MCS does not have an analytical form, a kriging-based response surface is built. Kriging-based response surface models are usually segment functions that do not have a uniform expression over the design space; however, most optimization algorithms require a uniform expression for constraints. To solve this problem, a heuristic gradient-based direct searching algorithm is proposed. These methods and algorithms, together with the RBDO general process, are applied to the layout optimization of aircraft floor grid structural design.
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Sardi, Alejandro Gabriel Del Castillo. "Development of a reliability program for adjusting aircraft functional check task intervals." Instituto Tecnológico de Aeronáutica, 2010. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=1299.
Full textAbstract:
The study evaluates an alternative for collection, monitoring and data analysis of functional check tasks during aircraft operation, analyzing new possibilities for adjusting (and extending) their intervals. A system of data collection and storage for a functional check task is proposed and ways to guarantee the quality, integrity, transparency and composition of the information is discussed. Methods to analyze the data are evaluated. Statistical models to monitor and provide subsidies are developed to aid decisions based on confidence level. The information is presented considering adaptation to approved formats and standards such as ATA SPEC 2000 (Chapter 11). Criteria for evaluating effectiveness of tasks and possible cases for extension / adjustment of tasks are developed. A case study is presented showing results that will bring economic benefits to airlines.
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Скрипець, Андрій Васильович, Володимир Дмитрович Тронько, and Олена Володимирівна Кожохіна. "RELIABILITY ASSESSMENT OF AIRCRAFT WITH REGARD OF INFORMATION FACTORS AND FEEDBACK LOOPS." Thesis, Національний авіаційний університет, 2014. http://er.nau.edu.ua/handle/NAU/11069.
Full textAbstract:
Considered calculation of the probability of failure-free operation ergatic the aircraft and the pilot on the example of flight control channel rating the probability of failurefree operation is given based on the information and errors feedback.
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Pierotti, Mark J. "Aircraft Maintenance Engineering : developing Aircraft Maintenance Programme using Reliability Centred Maintenance/MSG3 analysis and taking into consideration ETOPs and low utilisation." Thesis, City University London, 2005. http://openaccess.city.ac.uk/8461/.
Full textAbstract:
The thesis is entitled "Aircraft Maintenance Engineering: Developing an Aircraft Maintenance Programme using Reliability Centred Maintenance/ MSG3 Analysis Taking into Consideration ETOPS and Low Utilisation", It brings together and explains an area that the author feels is not well documented or published today in the world of aviation maintenance management, yet it is fundamental on the continued airworthiness of an aircraft, it can be considered as the building block for maintaining the inherent reliability and airworthiness of the design. It is the author's experience that too many times operators have attempted to carry out the function of maintenance engineering with out full understanding of the reasons and implication of their actions, thus ending up with an ineffective and non applicable collection of maintenance activities that can only add to the expense of the technical operation and even at times contribute to the possibility of occurrences. The thesis also goes on to develop new decision tree diagrams based upon Reliability Centred Maintenance (RCM) / Maintenance Steering Group 3 (MSG3) analysis for the use in developing the Maintenance and Reliability Programme and incorporating new aspects of aircraft operation.
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Wilson, Joseph Scott. "Uncertainty quantifiation with mitigation actions for aircraft conceptual design." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53586.
Full textAbstract:
There are always differences between conceptual design estimates and the performance of a final product. These differences may result in constraint violations, which can have severe financial impacts. Such violations may necessitate downstream changes to recover aircraft performance. The ability to estimate the likelihood and impact of late-stage changes is key to mitigating the overall risk of a design.
Reliability methods can treat design uncertainty; however, existing methods do not account for aspects of aircraft design such as sizing processes, the design freeze after conceptual design, and late-stage ``mitigation actions'' taken when a performance constraint is violated. By accounting for these elements, new reliability metrics can be developed. In addition to the probability of compliance, the designer can determine the probability of recovery through mitigation actions, which helps determine the true likelihood that a design can meet the requirements.
Hypotheses are developed to fill the identified gaps, resulting in Aircraft Recovery through Mitigation & Optimization under Uncertainty for Reliability. ARMOUR augments reliability methods by integrating aircraft sizing, uncertainty margins, and mitigation actions. ARMOUR is demonstrated on the conceptual design of a large civil transport and is exercised to explore previously obscured relationships.
The field of probabilistic aircraft design is enhanced by the concurrent quantification of three elements in one design environment: probability of compliance, probability of recovery after failure, and traditional design criteria. ARMOUR enables the identification of designs which both meets reliability goals and optimizes a traditional performance metric, selecting a design that efficiently meets reliability requirements.
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Che, Yunxiang, and S3145469@student rmit edu au. "Aging structure life prediction and reliability assessment." RMIT University. SAMME, 2008. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20091113.114541.
Full textAbstract:
Confront with the serious aging problem in aircraft structure field, the profession was tasked to unveil the mysterious in the mechanism of aging. In decades, many endeavours were put into different subjects such as, fatigue and crack calculation, corrosion analysis, reliability evaluation, life prediction, structure monitor and protection, structure repair, etc. In an effort of developing a reasonable model for life prediction and reliability evaluation, a wide range of topics in the field of aging structure reliability are reviewed. Many existing methods and tools are carefully studied to distinguish the advantages, disadvantages and the special application. With consideration of corrosion fatigue life, and based on the data obtained through investigating service status of the aging aircraft, a fuzzy reliability approach is proposed and presented. Initially, the thesis presents the literature review in the field, introducing the well-established theories and analysis tools of reliability and points out how such these methods can be used to assess the life and reliability of aging structure. Meanwhile, some characteristic parameters and distributions, as well as some crucial calculation formulations, procedures for aging aircraft reliability/risk analysis are given. Secondly, mathematical models are established to evaluate the initial crack size and to assess both randomness and fuzziness of the variables, which also successfully work out the probability of survival of existing structures over a time period and predict the operation time under specific reliability requirement. As a practical approach to the reliability of aging aircraft structure, example is presented and evaluated. While conduct the calculation, a few programs based on FORTRAN code are developed to solve the none-linear equation, to work out the multi dimension integration and to simulate the survival probability. The crack life prediction software AFGROW is selected for comparison of the calculation results, which also shows the appropriate accuracy of the established model. As conclusion, the effects of some variables including fuzzy factors on reliability and life of aging aircraft structure are finally discussed. It is apparent that the confines of the model are existing as fact because of the huge assumption of the parameters input and model uncertainties. Suggestions on further prospective research are proposed respectively.
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Basnet, Saurav Man Singh. "Development of salient pole rotor for conventional automotive and aircraft alternator to increase reliability." Thesis, Wichita State University, 2007. http://hdl.handle.net/10057/1517.
Full textAbstract:
This thesis includes the redesign and construction details of a salient pole rotor for an existing aircraft alternator. Salient pole rotor was designed to increase reliability of the conventional automotive and aircraft alternator. Details of the mechanical and electrical design methodology and implementation are included. Various parameters considered for design are also explained. The designed rotor matches the dimensions of the conventional automotive and aircraft alternator rotor, since the same alternator stator was used. The stator had a three phase delta-connected winding. It is used in aircraft to charge a battery at various modes of operation, as explained here. The experimental results of conventional automotive and aircraft alternator rotors and the salient pole rotor are compared and discussed. The salient pole rotor experiment included various air gaps and different field-winding tests. The rotor design is not exactly as required, but a thorough understanding of different aspects of the machine was achieved. Guidelines for further modifications are included in this thesis.Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Electrical and Computer Engineering
"December 2007."
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Basnet, Saurav Man Singh Jewell Ward T. "Development of salient pole rotor for conventional automotive and aircraft alternator to increase reliability /." Thesis, A link to full text of this thesis in SOAR, 2007. http://hdl.handle.net/10057/1517.
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Herbert, Lael S. (Lael Stefan) 1977. "Designing for reliability, maintainability, and sustainability (RM&S) in military jet fighter aircraft engines." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/82251.
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Jakl, Jan. "Funkční analýza rizik (FHA) 4-místného letounu pro osobní dopravu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-229297.
Full textAbstract:
At the beginning this master's thesis includes of a comprehensive review of aircraft accidents in this category, 2-6-digit aircraft for passenger transport. Since this work focused on autopilot, so naturally there is a basic overview of most common autopilots, which can be found in these aircraft now, but in the future. Functional hazard analysis (FHA) for the 4-seater plane for passenger services primarily investigates cases of catastrophic malfunction, which in most cases accompanied by the likelihood taken from different databases. The airplane, which is created for this analysis will preferably equipped with instruments for IFR flights. There is also a brief overview of the regulations necessary for the installation of these systems in the airplane. At the end of this work is to design the dashboard, a design layout of equipment for future aircraft, with an emphasis on maximum transparency.
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Armstrong, Michael James. "Identification of emergent off-nominal operational requirements during conceptual architecting of the more electric aircraft." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/42872.
Full textAbstract:
With the current increased emphasis on the development of energy optimized vehicle systems architectures during the early phases in aircraft conceptual design, accurate predictions of these off-nominal requirements are needed to justify architecture concept selection. A process was developed for capturing architecture specific performance degradation strategies and optimally imposing their associated requirements. This process is enabled by analog extensions to traditional safety design and assessment tools and consists of six phases: Continuous Functional Hazard Assessment, Architecture Definition, Load Shedding Optimization, Analog System Safety Assessment, Architecture Optimization, and Architecture Augmentation.
Systematic off-nominal analysis of requirements was performed for dissimilar architecture concepts. It was shown that traditional discrete application of safety and reliability requirements have adverse effects on the prediction of requirements. This design bias was illustrated by cumulative unit importance metrics. Low fidelity representations of the loss/hazard relationship place undue importance on some units and yield under or over-predictions of system performance.
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Spitler, William Walter. "A study of reliability centered aircraft maintenance and opportunities for application by the United States Coast Guard." Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/59602.
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Campbell, Angela Mari. "Architecting aircraft power distribution systems via redundancy allocation." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53087.
Full textAbstract:
Recently, the environmental impact of aircraft and rising fuel prices have become an increasing concern in the aviation industry. To address these problems, organizations such as NASA have set demanding goals for reducing aircraft emissions, fuel burn, and noise. In an effort to reach the goals, a movement toward more-electric aircraft and electric propulsion has emerged. With this movement, the number of critical electrical loads on an aircraft is increasing causing power system reliability to be a point of concern.
Currently, power system reliability is maintained through the use of back-up power supplies such as batteries and ram-air-turbines (RATs). However, the increasing power requirements for critical loads will quickly outgrow the capacity of the emergency devices. Therefore, reliability needs to be addressed when designing the primary power distribution system.
Power system reliability is a function of component reliability and redundancy. Component reliability is often not determined until detailed component design has occurred; however, the amount of redundancy in the system is often set during the system architecting phase. In order to meet the capacity and reliability requirements of future power distribution systems, a method for redundancy allocation during the system architecting phase is needed.
This thesis presents an aircraft power system design methodology that is based upon the engineering decision process. The methodology provides a redundancy allocation strategy and quantitative trade-off environment to compare architecture and technology combinations based upon system capacity, weight, and reliability criteria.
The methodology is demonstrated by architecting the power distribution system of an aircraft using turboelectric propulsion. The first step in the process is determining the design criteria which includes a 40 MW capacity requirement, a 20 MW capacity requirement for the an engine-out scenario, and a maximum catastrophic failure rate of one failure per billion flight hours. The next step is determining gaps between the performance of current power distribution systems and the requirements of the turboelectric system. A baseline architecture is analyzed by sizing the system using the turboelectric system power requirements and by calculating reliability using a stochastic flow network. To overcome the deficiencies discovered, new technologies and architectures are considered. Global optimization methods are used to find technology and architecture combinations that meet the system objectives and requirements. Lastly, a dynamic modeling environment is constructed to study the performance and stability of the candidate architectures. The combination of the optimization process and dynamic modeling facilitates the selection of a power system architecture that meets the system requirements and objectives.
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Schallert, Christian [Verfasser]. "Integrated Safety and Reliability Analysis Methods for Aircraft System Development using Multi-Domain Object-Oriented Models / Christian Schallert." München : Verlag Dr. Hut, 2015. http://d-nb.info/1080754547/34.
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Johansson, Cristina. "On System Safety and Reliability Methods in Early Design Phases : Cost Fo cused Optimization Applied on Aircraft Systems." Licentiate thesis, Linköpings universitet, Maskinkonstruktion, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-94354.
Full textAbstract:
System Safety and Reliability are fundamental to system design and involve a quantitative assessment prior to system development. An accurate prediction of reliability and system safety in a new product before it is manufactured and marketed is necessary as it allows us to forecast accurately the support costs, warranty costs, spare parts requirements, etc. On the other hand, it can be argued that an accurate prediction implies knowledge about failures that is rarely there in early design phases. Furthermore, while predictions of system performance can be made with credible precision, within reasonable tolerances, reliability and system safety are seldom predicted with high accuracy and confidence. How well a product meets its performance requirements depends on various characteristics such as quality, reliability, availability, safety, and efficiency. But to produce a reliable product we may have to incur increased cost of design and manufacturing. Balancing such requirements, that are often contradictory, is also a necessary step in product development. This step can be performed using different optimization techniques. This thesis is an attempt to develop a methodology for analysis and optimization of system safety and reliability in early design phases. A theoretical framework and context are presented in the first part of the thesis, including system safety and reliability methods and optimization techniques. Each of these topics is presented in its own chapter. The second and third parts are dedicated to contributions and papers. Three papers are included in the third part; the first evaluates the applicability of reliability methods in early design phases, the second is a proposed guideline for how to choose the right reliability method, and the third suggests a method to balance the safety requirements, reliability goals, and costs.
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Kross, Cory Kenneth. "A Method for Evaluating Aircraft Electric Power System Sizing and Failure Resiliency." DigitalCommons@CalPoly, 2017. https://digitalcommons.calpoly.edu/theses/1709.
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With the More Electric Aircraft paradigm, commercial commuter aircraft are increasing the size and complexity of electrical power systems by increasing the number of electrical loads. With this increase in complexity comes a need to analyze electrical power systems using new tools. The Hybrid Power System Optimizer (HyPSO) developed by Airbus SAS is a simulator designed to analyze new aircraft power systems. This thesis project will first provide a method to assess the reliability of complex aircraft electrical power systems before and after failure and reconfiguration events. Next, an add-on to HyPSO is developed to integrate the previously developed reliability calculations. Proof-of-concepts including new data visualizations are performed and provided.
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Martens, Scott L. "Estimating characteristic life and reliability of an aircraft engine component improvement in the early stages of the implementation process." Thesis, Monterey, California. Naval Postgraduate School, 1992. http://hdl.handle.net/10945/23879.
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Novák, Josef. "Metody analýzy spolehlivostních dat z provozu a zkoušek letadel." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-233972.
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The doctoral thesis deals with reliability (dependability) analyses of operation and testing data of the Airplanes. Requirements of airworthiness regulations on aircraft hydraulic systems (with a focus on US FAR-23 and European CS-23 regulations) are taken into account. Mentioned regulations include requirements for the structural design, design of systems, etc. They cover wide range of airplanes from small sport airplanes to 19-seats transport aircraft. Also options for predictive reliability analyses (resources) and reliability tests are discussed in the doctoral thesis. Practical application is done on small transport airplane (currently in the development). The failure report is designed. Expected major contribution of the work is selection and practical application of the most suitable procedures for safety assessment on the field of aircraft hydraulic systems, with a focus on the small transport aircraft. Also the comparison to different data source is shown.
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Janhuba, Luboš. "The Integrated Method Utilizing Graph Theory and Fuzzy Logic for Safety and Reliability Assessment." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-387740.
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Dizertační práce se zabývá návrhem integrované metody hodnocení bezpečnosti a spolehlivosti palubních leteckých systém za použití teorie grafů a fuzzy logiky. Navržená integrovaná metoda je univerzálně použitelná v oblasti hodnocení bezpečnosti a spolehlivosti, nicméně je primárně navržená pro použití v oblasti General Aviation a civilních bezpilotních prostředků. Současná podoba hodnocení spolehlivosti je téměř výhradně závislá na úsudku analytika. Použití komerčních softwarových nástrojů pro hodnocení spolehlivosti je extrémně nákladné, přičemž možnost přístupu a úpravy použitých algoritmů je minimální. Současný prudký vývoj palubních letecký systému je spojen s jejich zvyšující se komplexností a sofistikovaností. Integrovaná metoda používá teorii grafů, jako nástroj modelování funkčních závislostí mez jednotily prvky systému. Použití teorie grafu současně umožňuje daný systém analyzovat, hodnotit hustotu vzájemné funkční vazebnosti, identifikovat důsledky případných poruchových stavů. Aplikace fuzzy logiky umožňuje manipulovat s expertní znalostí a stanovit kritičnost daného prvku a systému. Kritičnost prvku zohledňuje pravděpodobnost jeho selhání, možnost detekce dané poruchy, závažnost těchto selhání vzhledem k vlivu na alokované funkce.
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Schallert, Christian [Verfasser], Robert [Akademischer Betreuer] Luckner, Robert [Gutachter] Luckner, and Martin [Gutachter] Otter. "Integrated safety and reliability analysis methods for aircraft system development using multi-domain object-oriented models / Christian Schallert ; Gutachter: Robert Luckner, Martin Otter ; Betreuer: Robert Luckner." Berlin : Technische Universität Berlin, 2016. http://d-nb.info/1156181852/34.
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Martins, Pires Rui Miguel. "Design methodology for wing trailing edge device mechanisms." Thesis, Cranfield University, 2007. http://hdl.handle.net/1826/3393.
Full textAbstract:
Over the last few decades the design of high lift devices has become a very
important part of the total aircraft design process. Reviews of the design process
are performed on a regular basis, with the intent to improve and optimize the
design process.
This thesis describes a new and innovative methodology for the design and
evaluation of mechanisms for Trailing Edge High-Lift devices. The initial research
reviewed existing High-Lift device design methodologies and current flap systems
used on existing commercial transport aircraft. This revealed the need for a design
methodology that could improve the design process of High-Lift devices, moving
away from the conventional "trial and error" design approach, and cover a wider
range of design attributes. This new methodology includes the use of the
innovative design tool called SYNAMEC. This is a state-of-the-art engineering
design tool for the synthesis and optimizations of aeronautical mechanisms. The
new multidisciplinary design methodology also looks into issues not usually
associated with the initial stages of the design process, such as Maintainability,
Reliability, Weight and Cost.
The availability of the SYNAMEC design tool and its ability to perform Synthesis
and Optimization of mechanisms led to it being used as an important module in
the development of the new design methodology. The SYNAMEC tool allows
designers to assess more mechanisms in a given time than the traditional design
methodologies.
A validation of the new methodology was performed and showed that creditable
results were achieved.
A case study was performed on the ATRA
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Advance Transport Regional Aircraft,
a Cranfield University design project, to apply the design methodology and select
from within a group of viable solutions the most suitable type of mechanism for the
Variable Camber Wing concept initially defined for the aircraft. The results show
that the most appropriate mechanism type for the ATRA Variable Camber Wing is
the Link /Track Mechanism. It also demonstrated how a wide range of design
attributes can now be considered at a much earlier stage of the design.
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Duek, Carlos. "ANÁLISE DE CONFIABILIDADE NA MANUTENÇÃO DE COMPONENTE MECÂNICO DE AVIAÇÃO." Universidade Federal de Santa Maria, 2005. http://repositorio.ufsm.br/handle/1/8428.
Full textAbstract:
Considering the actual technology available, an issue became crucial: to determine for how much time a critical device will be capable to perform, without failures, its function. When the operation of this device inlays a raised risk, as it occurs in
aviation, reliability is distinguished of the others dimensions of the quality, therefore the occurrence of failures can result in the loss of human lives and in damages to properties or to the environment. Under this perspective, the current work presents some basic concepts of reliability engineering, applied to the maintenance of aviation fleet, considering the characteristics of project, homologation set of laws, and
analyzing the possibilities of performance when compared to specifications. This study has as objective to analyze the reliability of aeronautical component, during the respective life cycle of an aircraft mechanical component, aiming at costs reduction and accident prevention. Therefore, a revision of the basic literature, focused on aircraft maintenance was realized, balancing consecrated theory with current articles
and thesis of varied areas of application of the reliability engineering. It was used a complementary view of the qualitative and quantitative approaches, to analyze the
performance of one specific mechanical component, chosen by its actual reliability, inconsistent with its specifications. In the first data collection, its reliability was measured and than, procedures to improve maintenance quality were defined. The
effectiveness of the adopted procedures was measured. The second data collection allowed to diagnosis an improvement in the performance of the component, although not being possible the quantification of such improvement, because of the necessary changes on data status.Com o atual desenvolvimento tecnológico, uma questão torna-se relevante: determinar por quanto tempo um dispositivo crítico será capaz de desempenhar, sem falhas, sua função. Quando a operação deste dispositivo embute um risco elevado, como ocorre na aviação, a confiabilidade destaca-se das demais dimensões da qualidade, pois a ocorrência de falhas pode resultar na perda de vidas humanas e danos ao patrimônio e ao ambiente. Assim sendo, o presente trabalho apresenta alguns conceitos básicos da engenharia da confiabilidade, aplicados à manutenção de aviação, considerando-se as características de projeto, regulamentos de homologação, e analisando-se as possibilidades de desempenho quando comparadas às especificações. O estudo teve como objetivo analisar a confiabilidade de material aeronáutico, por meio do exame do desempenho de um componente mecânico de aviação, durante o respectivo ciclo de vida, visando economia de meios e a prevenção de acidentes. Para tanto, efetuou-se uma revisão da literatura, focada na manutenção de aeronaves, balanceando-se a teoria consagrada com artigos e teses atuais de diversas áreas de aplicação da Engenharia da Confiabilidade. Após isso, por meio da complementaridade das abordagens qualitativa e quantitativa, analisou-se o desempenho de um determinado componente mecânico, escolhido devido sua baixa confiabilidade. Na primeira coleta de dados, mensurou-se sua confiabilidade e definiram-se procedimentos de melhoria da qualidade na manutenção. Em seguida, buscou-se avaliar a eficácia das medidas adotadas. Com os resultados obtidos da segunda coleta, conseguiu-se diagnosticar uma melhora na performance do citado componente, sem, contudo, viabilizar a quantificação de tal melhora.
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Dwire, Heather B. "RISK BASED ANALYSIS AND DESIGN OF STIFFENED PLATES." Wright State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=wright1208453129.
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Hartman, Matěj. "Funkční analýza rizik (FHA) malého letounu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-230779.
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The object of this diploma thesis is to perform Functional Hazard Assessment of small four-seat aircraft according to Federal Aviation Regulations Part 23, which would be similar to present aircrafts on market. Input data were acquired by research of systems aircrafts use on current market. On this basis the Functional Hazard Assessment was performed ad aircraft level. Total loss of power supply was qualified as Catastrophic therefore is used in following assessment. A preliminary failure rate assessment of typical parts used in electrical system was performed at the end of diploma thesis. For the most crucial parts a simple model was created and failure rate computed.
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Novotný, Tomáš. "Řízení údržby letadel a odstraňování závad při provozu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2009. http://www.nusl.cz/ntk/nusl-228366.
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This diploma thesis cover with the management of aircraft maintenance, one specific airline which operating with aircraft SAAB 340. Especially I dedicated to the maintenance and troubleshooting on the aircraft found during the operation. Contents diploma thesis consists of three parts. The first part describes the basic elements and concepts in the field of aircraft maintenance and related regulations. The next part describes the company which operating the aircraft for commercial transport, approach to the maintenance of its own fleet, together with the methodology for recording faults or malfunctions found during the operation. In the last part, I am cover with assessment of the system recording and troubleshooting.
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Ran, Hongjun. "A Framework for the Determination of Weak Pareto Frontier Solutions under Probabilistic Constraints." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14511.
Full textAbstract:
A framework is proposed that combines separately developed multidisciplinary optimization, multi-objective optimization, and joint probability assessment methods together but in a decoupled way, to solve joint probabilistic constraint, multi-objective, multidisciplinary optimization problems that are representative of realistic conceptual design problems of design alternative generation and selection. The intent here is to find the Weak Pareto Frontier (WPF) solutions that include additional compromised solutions besides the ones identified by a conventional Pareto frontier. This framework starts with constructing fast and accurate surrogate models of different disciplinary analyses. A new hybrid method is formed that consists of the second order Response Surface Methodology (RSM) and the Support Vector Regression (SVR) method. The three parameters needed by SVR to be pre-specified are automatically selected using a modified information criterion based on model fitting error, predicting error, and model complexity information. The model predicting error is estimated inexpensively with a new method called Random Cross Validation. This modified information criterion is also used to select the best surrogate model for a given problem out of the RSM, SVR, and the hybrid methods. A new neighborhood search method based on Monte Carlo simulation is proposed to find valid designs that satisfy the deterministic constraints and are consistent for the coupling variables featured in a multidisciplinary design problem, and at the same time decouple the three loops required by the multidisciplinary, multi-objective, and probabilistic features. Two schemes have been developed. One scheme finds the WPF by finding a large enough number of valid design solutions such that some WPF solutions are included in those valid solutions. Another scheme finds the WPF by directly finding the WPF of each consistent design zone. Then the probabilities of the PCs are estimated, and the WPF and corresponding design solutions are found. Various examples demonstrate the feasibility of this framework.
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Bednář, Ondřej. "Návrh údržbových prací pro malý dopravní letoun." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231649.
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The aim of this thesis is to design maintenance work for a small transport aircraft. This thesis is focused on an overview of the activities, which are carried out in the maintenance of small transport aircraft with a capacity about fifty passengers. The first part of this thesis is conceived as a theoretical part and summarizes the activities used during maintenance - maintenance methods, a typical part failures, diagnostics, network analysis and equations for the calculating of the cost of maintenance. At the beginning are showed the basic characteristics of selected representatives of this category and regulatory requirements on them. The design of maintenance work is in the second half of the thesis. It includes the visualization of the database that could be used for the maintenance of aircraft and which could be subsequently evaluated. This is a general description of the maintenance work, which ca be performed during the pre-flight inspection, re-inspection for repeated flights, preliminary preparation and periodic maintenance.
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Lowas, Albert Frank III. "Improved Spare Part Forecasting for Low Quantity Parts with Low and Increasing Failure Rates." Wright State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=wright1432380369.
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Mattrand, Cécile. "Approche probabiliste de la tolérance aux dommages." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2011. http://tel.archives-ouvertes.fr/tel-00738947.
Full textAbstract:
En raison de la gravité des accidents liés au phénomène de fatigue-propagation de fissure, les préoccupations de l'industrie aéronautique à assurer l'intégrité des structures soumises à ce mode de sollicitation revêtent un caractère tout à fait essentiel. Les travaux de thèse présentés dans ce mémoire visent à appréhender le problème de sûreté des structures aéronautiques dimensionnées en tolérance aux dommages sous l'angle probabiliste. La formulation et l'application d'une approche fiabiliste menant à des processus de conception et de maintenance fiables des structures aéronautiques en contexte industriel nécessitent cependant de lever un nombre important de verrous scientifiques. Les efforts ont été concentrés au niveau de trois domaines dans ce travail. Une méthodologie a tout d'abord été développée afin de capturer et de retranscrire fidèlement l'aléa du chargement de fatigue à partir de séquences de chargement observées sur des structures en service et monitorées, ce qui constitue une réelle avancée scientifique. Un deuxième axe de recherche a porté sur la sélection d'un modèle mécanique apte à prédire l'évolution de fissure sous chargement d'amplitude variable à coût de calcul modéré. Les travaux se sont ainsi appuyés sur le modèle PREFFAS pour lequel des évolutions ont également été proposées afin de lever l'hypothèse restrictive de périodicité de chargement. Enfin, les analyses probabilistes, produits du couplage entre le modèle mécanique et les modélisations stochastiques préalablement établies, ont entre autre permis de conclure que le chargement est un paramètre qui influe notablement sur la dispersion du phénomène de propagation de fissure. Le dernier objectif de ces travaux a ainsi porté sur la formulation et la résolution du problème de fiabilité en tolérance aux dommages à partir des modèles stochastiques retenus pour le chargement, constituant un réel enjeu scientifique. Une méthode de résolution spécifique du problème de fiabilité a été mise en place afin de répondre aux objectifs fixés et appliquée à des structures jugées représentatives de problèmes réels.
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Tsai, Li-Nung, and 蔡立農. "A Study of Aircraft Maintenance Reliability Control Program." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/43470376000569405361.
Full textAbstract:
碩士國立成功大學
交通管理學系碩博士班
94
Airlines’ reliability control program is aiming at discovering root causes of poor aircraft system or component reliability through monitoring their performances and execute appropriate corrective actions involving changes of aircraft maintenance program(AMP), modification of aircraft system or component, and relevant training requirements to ensure the reliability performance of aircraft system or component are within the predetermined and acceptable level. As for aircraft system reliability, it is the monthly technical delay and cancellation rate that is used to monitor each aircraft systems’ performance respectively. For those aircraft systems whose three-month rolling average delay rate exceed the predetermined upper control limit(UCL), which will generate “Alert”, engineers should conduct investigations to find out root causes and propose corrective actions to restore the system performance to an acceptable level. Therefore, the goal of this research is to analyze real technical delay and cancellation data through different approaches including analysis of variance(ANOVA) and logistic regression modeling to discuss the possible deficiencies of setting up UCL. At the same time, this research also proposes three different methods of setting up the UCL, and further applies the methodology of system simulation to conduct the experimental test of those proposed settings. The result of this research recommends that in considering the successful alert ability, false alert conditions, and flight delay and investigation cost, it is better to conduct investigations when continued alert signal appeared, and use the upper limit of 90% confidence interval of previous year’s average 3-month rate to set up next year’s UCL and compare it with the 3-month rate of the next year. On the other hand, if the cost of each investigation is 40% higher than each flight delay cost, it is suggested that setting up the UCL with the upper limit of 95% confidence interval of the previous year’s average monthly rate, and compare it to next year’s 3-month rolling average rate will be more suitable. The main contribution of this research is to provide a guideline of adjusting UCL. However, exactly which method to apply is deeply depending on each airlines policy and the difference of its flight delay and investigation cost.
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Chiang, Pu-Hai, and 蔣步海. "An Analysis of Reliability and Maintainability based on Aircraft Maintenance." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/04472254094158595458.
Full textAbstract:
碩士逢甲大學
工業工程與系統管理學研究所
93
The current maintenance system of the national defense industry shall be schemed to complete and establish an integrated logistics support management system of the military aircraft commercial maintenance in the future, so as to provide a main information link system that carries out the military maintenance businesses. The methods of maintenance data collection and work orders release is base on Maintenance Data Collection Record (MDCR), for completely establishing the system of maintenance data statistical analysis and advance material preparation of the military aircraft commercial maintenance. The amendatory service of military aircraft in maintenance workshops and modification are subjected to the maintenance work. The MDCR collection firstly establishes a complete system of material preparation data and inputs related information into MDCAS (Maintenance Data Collection Analysis System) and joins with TLS (Total Logistic Support). Maintenance data analysis would be regarded as important consultation and direction to reliability, maintainability and logistic support . The complete statistical analysis of maintenance data of logistics engineering is concluded by providing MDCR of related maintenance data, For the military aircraft commercial maintenance in the future, the main purpose of maintenance operation of MDCR is to access promptly required information, via data collection, storage, statistics and analysis, and to transfer required information so as to improve the logistic ability of integrated national defense.