580 research outputs found
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
Full text link32nd 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 hydraulic power system diagnostic, prognostics and health management
Full text linkThis 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
Optimal design of a composite wing structure for a flying-wing aircraft subject to multi-constraint
Full text linkThis 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
Author 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
Design, Fabrication, and Performance Test of a Hovering-Based Flapping-Wing Micro Air Vehicle Capable of Sustained and Controlled Flight
No full textWe present our insect-based hovering Flapping-Wing Micro Air Vehicle (FW-MAV) capable of sustained flight and control. The proposed design combines two fixed wings and two flapping wings to take advantage of the double clap-and-ling effects at the end of each half-stroke during one flapping cycle for high thrust production, and utilizes the fixed wings as the stabilizing surfaces and lift enhancement mechanism in forward flight. The FW-MAV has a wing span of 22 cm from wing tip-to-wing tip, weighs about 14.6 grams with onboard integration of radio control system including a radio receiver, an electronic speed control (ESC) for brushless motor, two servos for attitude flight controls of pitch and yaw, and a single cell lithium polymer (LiPo) battery (3.7 V). Moreover, passive wing rotation is utilized to simplify the design. Powered by the single cell LiPo battery, the FW-MAV can produce enough vertical thrust of 14.76 grams for lift-off at 10 Hz, and flap at maximum frequency of 12.4 Hz with average vertical thrust of about 24 grams. Experimental results show that the effect of wing clap significantly enhances thrust generation of about 44.82% when compared to the case without clap-and-fling effect, and the thrust-to-power ratio of the FW-MAV is about 3.93. Finally, free flight tests in terms of vertical take-off, hovering, and manual attitude control flight have been conducted to verify the flight performance of the insectinspired FW-MAV. Onboard equipped with a 70 mAh LiPo battery, the FW-MAV can demonstrate a sustained and controlled flight of about three minutes
Perencanaan dan Pembuatan Bisnis Scrub Rempah "FW Beautee" (Tinjauan Aspek Pemasaran)
Full text link"FW Beautee" spice scrub is an innovative scrub product made from black sticky rice. The purpose of this final project is to find out the marketing strategy, marketing mix, the constraints faced and how to solve these problems. This final project is implemented with 4 (four) methods, namely project preparation plan, project implementation plan, project completion plan and project reporting plan. The result of the implementation of this final project is that the market segmentation used is geographic segmentation, namely the Bengkalis Regency area, especially Bengkalis District. Demographic segmentation targets all types of people and all genders. Psychographic segmentation targets the entire community, especially those who like to take care of the body. The target market is all people from teenagers to adults and all genders, especially those who like scrubs. We position the "FW Beautee" spice scrub as a skin beauty product with natural herbal ingredients that no competitor produces with the same ingredients in Bengkalis and maintains good quality. Sales are carried out by delivery and promote products through social media. The obstacle faced is the doubts of potential consumers to buy the "FW Beautee" spice scrub product due to the consumer's fear of skin incompatibility with the product. In overcoming the obstacles faced during marketing, the author shows several testimonials that have been obtained from previous consumers in order to be more convincing to new potential customers
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