aircraft component
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2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Chunxiao Zhang ◽  
Xinwang Li ◽  
Xiaona Liu ◽  
Qiang Li ◽  
Yizhou Bai

PurposeThe purpose of this paper is to focus on an optimizing maintenance policy with repair limit time for a new type of aircraft component, in which the lifetime is assumed to be an uncertain variable due to no historical operation data, and the repair time is a random variable that can be described by the experimental data.Design/methodology/approachTo describe this repair limit time policy over an infinite time horizon, an extended uncertain random renewal reward theorem is firstly proposed based on chance theory, involves uncertain random interarrival times and stochastic rewards. Accordingly, the uncertain random programming model, which minimized the expected maintenance cost rate, is formulated to find the optimal repair limit time.FindingsA numerical example with sensitivity analysis is provided to illustrate the utility of the proposed policy. It provides a useful reference and guidance for aircraft optimization. For maintainers, it plays an important guiding role in engineering practice.Originality/valueThe proposed uncertain random renewal reward process proved useful for the optimization of maintenance strategy with maintenance limited time for a new type of aircraft components, which provides scientific support for aircraft maintenance decision-making for civil aviation enterprises.


2021 ◽  
Author(s):  
Huiyong Wu ◽  
shuchun jin ◽  
zhu jin

Abstract To effectively analyze the working state of the air circulation system when the aircraft flies at high altitude, it is necessary to simulate and analyze on the ground. A simulated annealing-grasshopper algorithm is proposed to optimize the support vector machine ( SAGOA-SVM ). The overall simulation model of the aircraft air circulation system is established, and the fault injection analysis is carried out. The support vector machine is introduced to classify the system results. The grasshopper algorithm simulated annealing and position offset are used to optimize the support vector machine, and the optimal parameter values are obtained. The results show that the simulation system can effectively simulate the temperature changes of the aircraft under various operating conditions. The optimized support vector machine can effectively distinguish the fault types of the aircraft component outlet, and the system convergence speed is accelerated to avoid the problem of falling into the local optimal value.


2021 ◽  
Author(s):  
Marcel Lewke ◽  
Soren Nielsen ◽  
Alexander List ◽  
Frank Gartner ◽  
Thomas Klassen ◽  
...  

2021 ◽  
pp. 778-786
Author(s):  
Ellen E. Wright ◽  
Suzanne F. Uchneat

Abstract This article focuses on failure analyses of aircraft components from a metallurgical and materials engineering standpoint, which considers the interdependence of processing, structure, properties, and performance of materials. It discusses methodologies for conducting aircraft investigations and inspections and emphasizes cases where metallurgical or materials contributions were causal to an accident event. The article highlights how the failure of a component or system can affect the associated systems and the overall aircraft. The case studies in this article provide examples of aircraft component and system-level failures that resulted from various factors, including operational stresses, environmental effects, improper maintenance/inspection/repair, construction and installation issues, manufacturing issues, and inadequate design.


2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Xiaobin Shen ◽  
Yundan Tan ◽  
Rendong Yu ◽  
Xiaochuan Liu ◽  
Guiping Lin ◽  
...  

Water droplet changes its movement direction and velocity when it bypasses an aircraft component with the surrounding airflow or gets blown by air injection from the inner part. When the deflected droplet impacts on the downstream surface, its impingement characteristics would be different from those without the frontal effects. In this article, a Lagrangian method was developed to include those upstream effects on the droplet collection efficiency. Validation cases were carried out for a cylinder and an MS (1)-0317 airfoil, whereas a multielement airfoil and an engine cone with a hot air film-heating anti-icing system were computed to investigate the effects of the upstream component and air injection on the impingement characteristics of downstream surfaces. It is found that the present collection efficiencies are in good agreement with the experimental data and the simulation results obtained by the Eulerian and traditional Lagrangian methods when not affected by those upstream factors. The droplet deflections and trajectory crossings are observed clearly under the influence of the upstream component, and the Lagrangian results of downstream surfaces differ from those of the Eulerian method. In addition, due to the air injection from the inner engine cone, the peak collection efficiency on the cone surface increases with the decrease of the droplet diameter and the value even exceeds one when the droplet is small. This work is helpful for the understanding of the droplet motion and the accuracy of aircraft icing simulation.


2021 ◽  
Author(s):  
Kristína Šajbanová ◽  
◽  
Jozef Čerňan

The paper deals with the design optimization of the compressor stage with counter-rotating rotors, especially in order to create a model which, due to its parameters in real operation, would achieve the maximum possible values of efficiency. The primary goal of this work is to create a design of a compressor stage with counter-rotating rotors from a theoretical point of view. The compressor stage model is created using Inventor modelling software and the subsequent design evaluation and optimization is based on airflow analysis of the compressor stage using Ansys Discovery Live software. The secondary goal is to point out the existence and application of innovative and progressive technology of rapid prototyping in the world of aircraft component production and at the same time to emphasize its benefits in comparison with conventional production techniques applied in the initial stages of aircraft component production.


Author(s):  
Wim J.C. Verhagen ◽  
Thijs Oudkerk

Unplanned maintenance is a costly factor in aircraft operations. Predictive maintenance models aim to provide greater insight into future component and system behaviour. In the state of the art, a variety of statistical models and machine learning techniques, amongst others, are used to estimate component remaining useful life. These approaches commonly leverage technical information, such as sensor data. However, the use of data and techniques from other domains is not prevalent. One such example is the application of natural language processing to incorporate textual information, e.g. derived from pilot complaint data. In other words, does the presence and specific content of pilot complaints have potential to improve the predictability of component removals? In this research, data integration and processing from multiple disciplines are combined to address this question. Relevant words from pilot complaints are identified using a term frequency–inverse document frequency (TF-IDF) numerical analysis, after which the most relevant words are used as covariates in a proportional hazards model. Left truncation and right censoring is applied to limit the time-invariant nature of these covariates. The results in the form of hazard ratios indicate a hazard increase of several orders of magnitude with respect to baseline hazard, pointing towards potential value of including these words as predictive parameters.


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