643 research outputs found
Aircraft hydraulic power system diagnostic, prognostics and health management
No full textThis Individual Research Project (IRP) is the extension research to the group design project (GDP) work which the author has participated in his Msc programme. The GDP objective is to complete the conceptual design of a 200-seat, flying wing civil airliner—FW-11. The next generation aircraft design demands higher reliability, safety and maintainability.
With the development of the vehicle hydraulic system technology, the equipment and systems become more and more complex, their reliability and maintenance become more difficult for designers, manufacturers and customers. To improve the mission reliability and reduce life cycle cost, there is strong demand for the application of health management technology into airframe system design.
In this research, the author introduced diagnostic, prognostic and health management (DPHM) concept into the aircraft hydraulic power system development. As a brand new technology, it is a challenge to apply the DPHM techniques to on-board system. Firstly, an assumed hydraulic power system was designed for FW-11 by the author and used as the case in his IRP research. Then the crucial components and key parameters needed to be monitored were obtained based on Function Hazard Analysis and Failure Modes Effects Analysis of this system. The writer compared a few diagnostic and prognostic methods in detail, and then selected suitable ones for a hydraulic power system. A diagnostic process was applied to the hydraulic power system using a Case-based reasoning (CBR) approach, whilst a hybrid prognostic method was suggested for the system. After that, a diagnostic, prognostic and health management (DPHM) architecture of the hydraulic power system was designed at system level based on the diagnostic and prognostic research. The whole research work provided a general and practical instruction for hydraulic system design by means of DPHM application
Damage mechanism characterization of ±35° and ±55° FW composite tubes using acoustic emission method
No full textThe focus of this study is to investigate the mechanical properties, of ±35° and ±55° filament wound (FW) composite tubes under axial compression loading using the acoustic emission technique. For this purpose, material failure, crashworthiness characteristics, and the effect of each mechanism on the energy absorption capacity were studied using numerical and experimental approaches. Also, to identify and estimate the contribution percentage of damage mechanisms as well as how the damage grows in the specimens, the analysis of acoustic emission signals recorded during loading was performed. Digital image correlation was additionally used to capture displacement/strain contour maps. Finally, to analyze the effect of the winding pattern in the experimental test, the tubes were simulated using finite element analysis (FEA). For modeling of damage mechanisms, a 3D continuum damage model was used. The results of signal processing showed that by increasing the weaving angle of fibers from ±35° to ±55°, the separation of fibers from the matrix decreases, and the percentage of matrix crushing and fiber failure increases. The assessment of damage percentages showed that the reason for the large drop in force at ±55° compared to ±35° is the increase in matrix crushing. Furthermore, the failure behavior of FW tubes appeared to be dominated by local buckling, and the FEA effectively predicted the linear behavior and maximum load value of the composite tubes.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Ship Hydromechanics and Structure
Photometric study of two detached binaries FW Vel and BB Mon
No full text32nd International Physics Congress of Turkish-Physical-Society (TPS) -- SEP 06-09, 2016 -- Bodrum, TURKEYWe present the first analysis of photometric observations of two detached binary stars, FW Vel and BB Mon. Their V light curves from the All Sky Automated Survey were solved using Monte Carlo Search Method. The final solutions describe these two systems as Algol-like binary stars with detached configurations. The absolute parameters of the components of the systems were also estimated.Turkish Phys So
Aircraft landing gear extension and retraction control system diagnostics, prognostics and health management
No full textThis thesis contains the Group Design Project (GDP) work and Individual
Research Project (IRP) work.
The target of this GDP was to design a long range flying wing passenger aircraft
to meet the increasing global aircraft demand. The name of this flying wing
aircraft is FW-11. This is a project cooperated between Aviation Industry
Corporation of China (AVIC) and Cranfield University. The writer was involved in
the conceptual design stage of this project. The author was in charge of the
engine market, engine selection, engine sizing and performance.
The target of the IRP is to build a set of health management methods including
system real-time monitoring, accurate fault diagnosis and prognosis of major
components which are suitable for the aircraft landing gear extension and
retraction control system. These technologies have the capability to improve
mission reliability of the aircraft and the maintenance costs could be reduced.
Simultaneously, aircraft landing gear extension and retraction control system, as
one of the most important aircraft systems on-board, could directly affect the
flight safety. Consequently, diagnostic, prognostic and health management
(DPHM) technology is necessary for the system.
Based on the FHA, FMEA and FTA of the aircraft landing gear extension and
retraction control system, each of the catastrophic events, all the root causes
and their effects were identified. Synchronously, all the components which are
related to the catastrophic events were found. The rule-based expert system
diagnostic technology was chosen from the available approaches and it was
successfully applied on the system. Appropriate prognosis approach was
recommended for each component of the system according to the features of
components of the system. Finally, the DPHM architecture of the landing gear
extension and retraction control system was built
Aircraft fuel system prognostics and health management
No full textThis 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
Intra-articular Corticosteroid Injections in the Hip and Knee: Perhaps Not as Dangerous as They Want You to Believe?
No full textComment on: Intra-articular Corticosteroid Injections in the Hip and Knee: Perhaps Not as Safe as We Thought? Kompel AJ, Roemer FW, Murakami AM, Diaz LE, Crema MD, Guermazi A. Radiology. 2019 Dec;293(3):656-663. doi: 10.1148/radiol.2019190341. Epub 2019 Oct 15. PMID: 31617798 Review
Optimal design of a composite wing structure for a flying-wing aircraft subject to multi-constraint
No full textThis thesis presents a research project and results of design and optimization of a composite wing structure for a large aircraft in flying wing configuration. The design process started from conceptual design and preliminary design, which includes initial sizing and stressing followed by numerical modelling and analysis of the wing structure. The research was then focused on the minimum weight optimization of the /composite wing structure /subject to multiple design /constraints. The modelling, analysis and optimization process has been performed by using the NASTRAN code. The methodology and technique not only make the modelling in high accuracy, but also keep the whole process within one commercial package for practical application.
The example aircraft, called FW-11, is a 250-seat commercial airliner of flying wing configuration designed through our MSc students Group Design Project (GDP) in Cranfield University. Started from conceptual design in the GDP, a high-aspect-ratio and large sweepback angle flying wing configuration has been adopted. During the GDP, the author was responsible for the structural layout design and material selection. Composite material has been chosen as the preferable material for both the inner and outer wing components. Based on the derivation of structural design data in the conceptual phase, the author continued with the preliminary design of the outer wing airframe and then focused on the optimization of the composite wing structure. Cont/d
The association of boen attrition with knee pain and other MRI features of osteoarthritis
No full textAuthor keyword network mapping.
No full textSustainability issues such as food insecurity, climate change, land degradation, economic development and food waste are the actual most important challenges at the global level. Among them, the food waste (FW) challenge has a great magnitude, emphasizing the importance of examining this issue. Specifically, there is a need to focus on the household level. Thus, this study aims to investigate and identify the main factors influencing FW household behaviors on which policymakers and stakeholders could outline specific and sustainable strategies. Starting from a large number of published studies on this subject with a similar aim but focusing on specific Countries or contexts, the goal of our study is achieved through the implementation of a systematic literature review followed by a bibliometric review using the VOSviewer software. The selected query generated a total of 235 matching papers from which only 111 papers were collected for the bibliometric review because of the inclusion criteria. The analysis showed the existence of four major research strands: the largest one analyses the antecedents of behavior during food management, including the implementation of the Theory of Planned Behavior (TPB). Other detected topics are the economic impact of FW, the effects generated by the Covid-19 pandemic on consumer behaviors, and finally, the environmental and social effects of FW. The objective of this study is to investigate and identify the main factors influencing FW household behaviors. The obtained output represents useful information for policymakers and stakeholders to outline specific and sustainable strategies to reduce FW.</div
A Momentum-Guided Frank-Wolfe Algorithm
No full textWith the well-documented popularity of Frank Wolfe (FW) algorithms in machine learning tasks, the present paper establishes links between FW subproblems and the notion of momentum emerging in accelerated gradient methods (AGMs). On the one hand, these links reveal why momentum is unlikely to be effective for FW-type algorithms on general problems. On the other hand, it is established that momentum accelerates FW on a class of signal processing and machine learning applications. Specifically, it is proved that a momentum variant of FW, here termed accelerated Frank Wolfe (AFW), converges with a faster rate on such a family of problems, despite the same rate of FW on general cases. Distinct from existing fast convergent FW variants, the faster rates here rely on parameter-free step sizes. Numerical experiments on benchmarked machine learning tasks corroborate the theoretical findings
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