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Bisták, Andrej, and Zdenka Hulínová. "Construction of ropeways in Slovakia in terms of pre-construction design using helicopters (case study)." MATEC Web of Conferences 263 (2019): 01002. http://dx.doi.org/10.1051/matecconf/201926301002.
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Ropeways usually provide access to locations inaccessible to other means of transport. Due to this fact, the construction of ropeways is extraordinarily taxing in terms of both, technology and logistics. The site location is often in terrain difficult to access, which often precludes deployment of common construction mechanisms in ropeway construction. In such case, it is advisable to deploy a transport mechanism independent of the terrain – a helicopter. Functioning as “flying cranes“, the helicopters have been used in construction industry in Slovakia for six decades now. Having amassed positive experience, even the “conventional“ construction industry of the time, especially its ropeway transport segment, started to use the benefits of helicopters, with helicopter deployment subsequently gaining ground and becoming the mainstream technological procedure. Ropeway construction can hardly be feasible without them even nowadays. Throughout the history of helicopter deployment in construction industry, a constant search of improving the efficiency of their work has been under way, necessitated by the helicopter’s sensitivitiy to weather conditions and work procedures alike. The paper presents an analysis of the factors affecting helicopter operation together with a proposed methodology of modeling their work in simulation models and the benefits of such approach.
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Гребеников, А. Г., Ю. В. Дьяченко, В. В. Коллеров та ін. "АНАЛІЗ КОНСТРУКТИВНО-ТЕХНОЛОГІЧНИХ ОСОБЛИВОСТЕЙ ЛОПАТЕЙ НЕСУЧИХ ГВИНТІВ ВАЖКИХ ТРАНСПОРТНИХ ВЕРТОЛЬОТІВ". Open Information and Computer Integrated Technologies, № 93 (19 листопада 2021): 59–103. http://dx.doi.org/10.32620/oikit.2021.93.04.
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The analysis of the design and technological features of the rotor blades of heavy transport helicopters is carried out. The main performance characteristics of heavy helicopters are presented. General requirements to helicopter main rotor blades design and specifications for their production are formulated. The design and force diagram of heavy helicopter main rotor blades is considered. The features of structural materials for the main rotor blades of heavy transport helicopters are marked. The main rotor blades differ in their design due to different approaches to materials, manufacturing and layout of blade elements. The main rotor blades of an all-metal design, for design and technological reasons, are divided into two groups: a frame structure with a tubular steel spar and an aluminum extruded spar. As a result of a number of design and technological measures the service life of the main rotor blade of helicopter Mi-6 was brought from 50 hours to 1500 hours. The principal peculiarity of the steel tubular spar of the main rotor blade of the Mi-26 helicopter is the absence of the shaft lug. The features of mixed design main rotor blades are presented. The method of parametric modeling of helicopter main rotor blades is presented. The application of the three-dimensional parametric models of structural elements in practice of designing and construction enables to perform numerical calculations of aerodynamic and strength characteristics both of separate aggregates, units and details and of the helicopter as a whole by means of the finite element method. The method of parametric modeling of the main rotor blade of the transport helicopter with the computer system CATIA V5 is a modification of the method of integrated designing of the elements of aviation constructions. Parametric master geometry of the main rotor blade is a linear surface, created by basic profiles of the blade. On the basis of parametric master geometry a space distribution model is created that determines the position of axial planes of the power set of the blade for further creation of the blade detail models. Technological flowchart of main rotor blade manufacturing is presented, manufacturing and surface hardening technology of steel tubular spar is considered. The technology of manufacturing and molding the nose part of the blade of the main rotor mixed design. The technological features of slipway assembly-gluing of the main rotor blade are considered, the content of off-slipway work is given.These materials can be useful in theoretical and experimental studies to extend the service life of the rotor blades of Mi-26 helicopters, which are currently in operation in Ukraine.
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Soldatkin, V. M., V. V. Soldatkin, A. V. Nikitin, and E. O. Ariskin. "Measuring System of Air Parameters of the Helicopter with a Stationary Receiver a Flow, Ion-Label and Aerometric Measurement Channels." Mekhatronika, Avtomatizatsiya, Upravlenie 19, no. 11 (2018): 744–52. http://dx.doi.org/10.17587/mau.19.744-752.
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It is shown that the known limitations on the measurement of air parameters on board the helicopter due to significant aerodynamic disturbances introduced by inductive flows of vortex column of main rotor. This determines the need to create the means of measurement, taking into account the aerodynamics and dynamics of the helicopter flight. The known direction of overcoming these limitations is the use for measuring the information of aerodynamic field of vortex column of main rotor and its perception by means of the stationary multi-functional aerometric receiver. However, the need to protect a large number of full-pressure tubes installed in the flow channel of the multifunctional aerometric receiver, strict requirements for the identity and stability of the characteristics of the large number aerometric channels, complicate the design, reduce reliability, increase cost, inhibit the use of the air parameters measurement system on helicopters of various classes and purposes. Principles of construction, functional scheme, features of perception of primary information of measuring system of air parameters of the helicopter with the stationary receiver of a stream, ion-label and aerometric measuring channels are showed. Algorithms for processing primary information at various stages and flight modes, including: in the parking lot before the launch of the power plant and when rotating the rotor, when taxiing and maneuvering on the earth’s surface, on takeoff and landing modes and when flying at low speeds, at flight speeds, when the stationary receiver of primary information leaves the zone of the vortex column of the rotor using ion-label and aerometric measuring channels, are presented. It is shown that the proposed approaches to the construction, models and algorithms for processing the primary information of the measuring system air parameters of helicopter with ion-label and aerometric measurement channels allow to determine the speed and direction of the wind vector, altitude-velocity parameters of motion relative to the environment and atmospheric parameters in a wide range of helicopter operation, which determines its competitive advantages in solving problems of piloting and provide the flight safety of helicopters of different classes and purposes.
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Soldatkin, V. M., and V. V. Soldatkin. "Research of Methodological Errors of the Air Data System of Aircraft with Stationary Included Receiver of Incoming Air Flow." Mekhatronika, Avtomatizatsiya, Upravlenie 20, no. 8 (2019): 504–12. http://dx.doi.org/10.17587/mau.20.504-512.
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It is shown that the known limitations on the measurement of air parameters on board the helicopter due to significant aerodynamic disturbances introduced by inductive flows of vortex column of main rotor. This determines the need to create the means of measurement, taking into account the aerodynamics and dynamics of the helicopter flight. The known direction of overcoming these limitations is the use for measuring the information of aerodynamic field of vortex column of main rotor and its perception by means of the stationary multi-functional aerometric receiver. However, the need to protect a large number of full-pressure tubes installed in the flow channel of the multifunctional aerometric receiver, strict requirements for the identity and stability of the characteristics of the large number aerometric channels, complicate the design, reduce reliability, increase cost, inhibit the use of the air parameters measurement system on helicopters of various classes and purposes. Principles of construction, functional scheme, features of perception of primary information of measuring system of air parameters of the helicopter with the stationary receiver of a stream, ion-label and aerometric measuring channels are showed. Algorithms for processing primary information at various stages and flight modes, including: in the parking lot before the launch of the power plant and when rotating the rotor, when taxiing and maneuvering on the earth’s surface, on takeoff and landing modes and when flying at low speeds, at flight speeds, when the stationary receiver of primary information leaves the zone of the vortex column of the rotor using ion-label and aerometric measuring channels, are presented. It is shown that the proposed approaches to the construction, models and algorithms for processing the primary information of the measuring system air parameters of helicopter with ion-label and aerometric measurement channels allow to determine the speed and direction of the wind vector, altitude-velocity parameters of motion relative to the environment and atmospheric parameters in a wide range of helicopter operation, which determines its competitive advantages in solving problems of piloting and provide the flight safety of helicopters of different classes and purposes.
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Shaidurova, Galina, Oleg Milman, Aleksey Kiryukhin, and Aleksandr Shaidurov. "Design and technological optimization of rubber-reinforced thin-layer movable joints in the structure of a pipeline vibration-isolating compensator." Revista Ingeniería UC 28, no. 3 (2021): 392–98. http://dx.doi.org/10.54139/revinguc.v28i3.47.
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Thin-layer rubber-metal elements have been widely used in various fields of technology, including helicopter construction, support parts for bridges, shock absorbers in industrial and civil construction. Their work reliability is determined by the design and technological performance features, which require experimental testing and parametric optimization. The article presents the samples and basic models testing results which were aimed at increasing the strength indicators stability of the adhesive ``rubber-metal'' joints and ensuring the failure-free operation of a rubber-metal product in the structure of a pipeline vibration-isolating compensator.
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Shahmiri, Farid. "Twin-rotor hover performance examination using overlap tests." Aircraft Engineering and Aerospace Technology 89, no. 1 (2017): 155–63. http://dx.doi.org/10.1108/aeat-02-2015-0032.
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Purpose The aim of this paper was to experimentally examine twin-rotor hover performance for different rotor overlap ratios at practical rotor loading. Design/methodology/approach The methodology was formed based on data measurements for a designed twin-rotor test model and development of hover performance mathematical models. Thus, measurements were made using a central composite test plan, and then mathematical models for thrust power required power loading (PL) and figure of merit (FM) as functions of collective pitch tip speed; rotor overlap ratio was obtained. In the present paper, the test model consisted of two three-bladed rotors with a diameter of 220 mm and a blade aspect ratio of 16.05. The blades were of a rectangular planform with NACA 0012 cross sections and had no twist or taper. The model was built such that the rear rotor was fixed on the fuselage, and the front rotor could move longitudinally for tests up to about 40 per cent overlap ratio in hover. Findings The best hover aerodynamic efficiency (maximum PL of 14.6 kg/kW) was achieved for non-overlapped rotors at a low value of disc loading (DL) and also at FM of 0.6 at that DL. This result was in agreement with blade element momentum theory predictions. Practical implications Results for the twin-rotor test model can be generalized for actual tandem helicopters through the Reynolds number transformation technique and also some modifications. Originality/value Design and construction of the twin-rotor test model and experimental measurements of hover performance based on an optimal test plan were performed for the first time.
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Олег Львович Лемко and І. В. Король. "Method of parametric studies of computational models first approximation of the aircraft with aerostatic SUPPORT." MECHANICS OF GYROSCOPIC SYSTEMS, no. 28 (May 20, 2015): 36–45. http://dx.doi.org/10.20535/0203-377128201439137.
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In recent years, scientists of the leading countries of the World, designers, specialists of different industries are paying close attention to aircrafts lighter than air. These aircraft use much less fuel than similar planes and helicopters with load capacity, capable to transport heavy loads on thousands of miles away, with the possibility of landing on unprepared sites or hang in the air for a long time with a cargo during the construction works. In addition, they provide a significant increase in safety of the flight in their exploitation.One of the most promising types of airships are aircraft with aerostatic support (hybrid airships) using two principles generate lift: aerodynamic and aerostatic. They can incorporate the best qualities of the airplane (speed), the airship (large capacity and range), and helicopter (the possibility of implementing a short or vertical takeoff and landing).For the formation of aerodynamic lift of the aircraft needs a wing only. All other units of aircraft not involved in the creation of lift is desirable to place inside the wing. Therefore, for the further research we chose an aerodynamic scheme called "flying wing". This scheme is the most rational for using the force of the aerostatic lifting gas, which is located inside the wing.To solve the problem in the research we used the method of calculation of the aerodynamic characteristics of aircraft in the parameters of similarity, which allows estimating the aerodynamic behavior of the wing-form in design with linear edges. It is necessary to determine the optimal layout of the wing and its aerodynamic performance in conditions of using more force of aerostatic lifting gas, concluded in the interior of the wing.With an increase of the relative profile thickness from 8% to 30% the maximal aerodynamic efficiency will be reduced from 14 to 11 units. However, the loss of quality can be compensated to fill the inner cavity of the wing lifting gas. This makes an additional component of the aerostatic force. For example the model with the relative thickness profile of 30%, and aerostatic lift 171 kg is considering.Thus we had made the analysis of changes in aerodynamic and aerostatic characteristics of the computational model of the first approximation of the aircraft with aerostatic support of the relative thickness profile. The expediency of using thick sections D-2 of the Central Aero-Hydrodynamic Institute for the aircraft scheme "flying wing" with aerostatic support was shown.As the analysis of dependencies КΣ = f (α) and the relative thickness of the wing profile = 30%, the maximum aerodynamic efficiency КΣ мах corresponds to 12 units. The same value of Кмах wing without aerostatic support in the relative thickness of the wing profile amounts 20% (= 20%).
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Al-Fatlawi, Alaa, Károly Jármai, and György Kovács. "Optimization of a Totally Fiber-Reinforced Plastic Composite Sandwich Construction of Helicopter Floor for Weight Saving, Fuel Saving and Higher Safety." Polymers 13, no. 16 (2021): 2735. http://dx.doi.org/10.3390/polym13162735.
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The application of fiber-reinforced plastic (FRP) composites as structural elements of air vehicles provides weight saving, which results in a reduction in fuel consumption, fuel cost, and air pollution, and a higher speed. The goal of this research was to elaborate a new optimization method for a totally FRP composite construction for helicopter floors. During the optimization, 46 different layer combinations of 4 different FRP layers (woven glass fibers with phenolic resin; woven glass fibers with epoxy resin; woven carbon fibers with epoxy resin; hybrid composite) and FRP honeycomb core structural elements were investigated. The face sheets were composed of a different number of layers with cross-ply, angle-ply, and multidirectional fiber orientations. During the optimization, nine design constraints were considered: deflection; face sheet stress (bending load, end loading); stiffness; buckling; core shear stress; skin wrinkling; intracell buckling; and shear crimping. The single-objective weight optimization was solved by applying the Interior Point Algorithm of the Matlab software, the Generalized Reduced Gradient (GRG) Nonlinear Algorithm of the Excel Solver software, and the Laminator software. The Digimat-HC software solved the numerical models for the optimum sandwich plates of helicopter floors. The main contribution is developing a new method for optimizing a totally FRP composite sandwich structure—due to its material constituents and construction—that is more advantageous than traditional helicopter floors. A case study validated this fact.
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Cai, Guowei, Lin Feng, Ben M. Chen, and Tong H. Lee. "Systematic design methodology and construction of UAV helicopters." Mechatronics 18, no. 10 (2008): 545–58. http://dx.doi.org/10.1016/j.mechatronics.2008.05.011.
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Küppers, Jan-Philipp, and Tamara Reinicke. "A WaveNet-based fully stochastic dynamic stall model." Wind Energy Science 7, no. 5 (2022): 1889–903. http://dx.doi.org/10.5194/wes-7-1889-2022.
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Abstract. Accurate modeling of the dynamic stall remains a challenge for the design and construction of turbine blades and helicopter rotors. At the same time, wind turbines, for instance, are becoming steadily larger, further increasing the demands on their structure and necessitating even more detailed modeling of the forces at hand. The primarily used (semi-)empirical models today have a long research history and are invariably based on phase-averaged data from oscillating blade pitch experiments. However, much potential for more accurate modeling of uncertainties and force peaks is wasted here, since averaging blurs many features of the response signals. Even computational fluid dynamics can help little in this regard, since the Reynolds-averaged Navier–Stokes equations used in practice cannot account for cycle variations, and scale-resolving models require extremely large amounts of computational resources. This paper presents an approach for a fully stochastic machine learning model that can nevertheless simulate these critical properties. Aerodynamic coefficients are compared with experimental data for different test cases. It is shown that synthetic force profiles which cannot be distinguished from the experimental data visually and are very close to them in the frequency spectrum can be generated. Additionally, attention is drawn to the difficulty of evaluating such a model, as traditional error metrics are of little use. A combination of dynamic time warping and the Earth mover's distance provides a robust solution for this problem.
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Knöös Franzén, Ludvig, Ingo Staack, Petter Krus, and Kristian Amadori. "Optimization Framework for Early Conceptual Design of Helicopters." Aerospace 9, no. 10 (2022): 598. http://dx.doi.org/10.3390/aerospace9100598.
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This work illustrates how a proposed method can be used to create optimization frameworks for early conceptual design studies and to increase overall knowledge at an early design stage. The method is intended to facilitate concept selection in challenging domains that typically involve multidisciplinary design problems with contradictory requirements. The main focus of the work presented here is on the conceptual design of helicopters; however, the method is intended to be applicable to early design studies in other domains as well. In short, statistics about existing helicopters are collected and compiled to provide a basis for various regression analyses. The purpose of this is to unravel relationships in the data and to obtain simple estimation models from statistical regressions that can be used in conjunction with existing formulas and equations to generate an initial helicopter design estimate. Models for each discipline, such as aerodynamics, are then created using the outcomes of the regression analyses and existing equations. Lastly, the method is used to define a multidisciplinary design optimization framework incorporating all the models obtained from the different disciplines. A case study based on search and rescue operations is used to test the proposed framework in order to obtain possible first suggestions for the baseline design of a new general-purpose search and rescue helicopter.
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Bisták, Andrej, Zdenka Hulínová, and Michal Neštiak. "Simulation Modelling of Aerial Works and Its Role in the Preparation of Construction." Slovak Journal of Civil Engineering 29, no. 1 (2021): 20–26. http://dx.doi.org/10.2478/sjce-2021-0004.
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Abstract The construction process is characterized by a diverse technological composition and the use of a wide range of construction machinery and mechanization. The amount of machinery increases with the complexity of the construction, which increases the demands concerning the preparation and overall organisation of the construction. The preparation of construction processes carried out by helicopters (aerial work) must respect the effect of randomly changing construction conditions as well as the specific working conditions of helicopters. The complexity of such a system can be modelled using simulation models. In the work presented, we designed and practically tested a simulation model of aerial work in the MATLAB software environment. An essential part of the simulation model is an algorithm designed on the basis of commercial numerical weather prediction models. We consider the outputs of the simulation to be reliable, because they are very close to the actual results achieved in the case of the implementation of construction of this type. The concept of the simulation model enables its wider use not only in the construction sector, but also in other branches of industry.
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Davidson, Gary, Tim Roberts, and Darren Savoye. "Skid Helicopters on High-Speed Craft." Journal of Ship Production 21, no. 02 (2005): 108–25. http://dx.doi.org/10.5957/jsp.2005.21.2.108.
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Helicopter decks are common throughout the commercial and military shipping industries and also the offshore industry. Construction in steel and aluminum is common. Helicopter decks on high-speed craft are not common. The first known helicopter deck installed on a high-speed craft was on an Incat wave-piercing catamaran, HSV X1, Joint Venture, which saw service during the recent Gulf war and is currently still in service with the US Army. Following successful construction and NAVAIR certification of Joint Venture, a more advanced aluminum deck, certified also by NAVAIR and Naval Sea Systems Command (NAVSEA), has been fitted to HSV 2 Swift, which is the latest Incat 98 meter "SeaFrame" HSC. HSV 2 Swift is in service with the US Navy. This paper will focus on the design challenge that came about on HSV 2 Swift in the design of the deck to land and park skid type helicopters as opposed to a helicopter with pneumatic tires. High-speed craft are by their nature innovative, and new solutions to old problems are constantly being experimented with to ensure that the tenets of high speed and high efficiency are optimized. Weight minimization is the most critical performance aspect of a high-speed craft, and conservative or simplified analysis is not practical or economic. A high-speed craft relies on accelerating through hump or critical speed to obtain the high operating speeds of around 40 knots and greater. The ability to operate above hump speed is absolutely reliant on the weight of the vessel. Unnecessary weight on the vessel that does not have absolute mission or operation justification adversely affects the ability to operate above hump speed. Aluminum creates additional and very different challenges compared to a design in traditional steel. Alternative details and construction techniques are required for successful design in aluminum in terms of fatigue and ultimate strength. One innovation common in high-speed craft is aluminum extrusion of a top hat form. The top hat offers big savings in terms of ultimate strength and reduction in mass while keeping weight to a minimum. To aid in verifying the design of the Helo deck extrusion on HSV 2 Swift (Incat Yard 061) for the AH-1 and UH-1 helicopters (H-1 series skid type helicopters), analysis and physical testing were carried out. There had been some doubt that conventional hand calculations were suitable for a top hat style extrusion. The analysis and testing proved that extruded aluminum sections of top hat design are suitable for the H-1 series helicopter skid loading and that permanent deformation was negligible at the design load and even at significantly above the design load. The physical test is also further evidence to support the use of welded 6000 series extrusion in high-speed military vessels. Original design of the deck extrusion revolved around class rules, linear static finite element analysis (FEA), and military codes. Later analysis involved nonlinear FEA, further military code calculations, first principles hand calculations based on available text, and physical testing.
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Bisták, A., Z. Hulínová, I. Vavrík, and P. Šťastný. "Aerial work with helicopters in the construction of cableways and their impact on the concrete mixture design." IOP Conference Series: Materials Science and Engineering 1252, no. 1 (2022): 012005. http://dx.doi.org/10.1088/1757-899x/1252/1/012005.
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Abstract Slovakia is a rugged country, a significant part of which consists of mountain areas. Construction activities in these localities should consider specific natural conditions, while taking into account economic issues. In these cases, the efficient way of construction is the use of aerial work, so the execution of constructions using helicopters. However, compared to conventional technologies, helicopters are limited in their work by several factors, which are mainly related to their movement in a three-dimensional environment (atmosphere). The aim of this article is to show how the choice of fresh concrete mixture is related to the work of helicopters, to design a suitable mixture for the currently valid Slovak requirements and to test it in laboratory conditions. The selection of the mixture is narrowly specialized for the construction of reinforced concrete footings of cableways, which are typically realized in mountain areas. The results showed that by using a suitable superplasticizer based on polycarboxylates, it is possible to ensure the required workability of fresh concrete within 180 minutes. However, the condition must always be met that the onset of setting of the used cement does not occur earlier than 180 minutes. Longer workability time can be achieved by adding a retarding additive.
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KACHEL, Stanisław, Robert ROGÓLSKI, and Jakub KOCJAN. "Review of Modern Helicopter Constructions and an Outline of Rotorcraft Design Parameters." Problems of Mechatronics Armament Aviation Safety Engineering 12, no. 3 (2021): 27–52. http://dx.doi.org/10.5604/01.3001.0015.2427.
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This work contains the results of a modern helicopter construction analysis. It includes the comparison of almost seventy rotorcraft constructions in terms of size in line with EASA requirements – large and small helicopters. The helicopters are also divided because of a mission purpose. The proposed division for large aircrafts is: transport, multipurpose, attack and for small aircrafts: observation, training, and utility. The aircraft construction features are described. Average dimension values of airframes and rotors are shown. Helicopter rotor arrangements are presented in terms of an operational purpose. Next, the rotorcraft design inputs are described. The mathematical formulas for design inputs are given. The ratios are calculated and gathered for the compared aircrafts. Correlation between the analysed parameters is presented on charts. Design inputs are also presented in the paper as a function of MTOW. The function trends are determined to provide an evaluation tool for helicopter designers. In addition, the parameters are presented as possible optimisation variables.
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Bisták, Andrej, Zdenka Hulínová, Michal Neštiak, and Barbara Chamulová. "Simulation Modeling of Aerial Work Completed by Helicopters in the Construction Industry Focused on Weather Conditions." Sustainability 13, no. 24 (2021): 13671. http://dx.doi.org/10.3390/su132413671.
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The aim of this research was to develop a simulation model of the works carried out by helicopters, which are used in the construction of buildings under harsh natural conditions. This work identified that even technologies that we do not normally encounter, such as aerial work using helicopters, can have a major impact on ensuring the requirement of sustainability within the overall environmental and economic context. In the environment of protected landscape areas and national parks, in particular, where all sites are sensitive to human intervention, the use of helicopters in construction functions is an irreplaceable aid. Preparations for aerial work are very demanding and require the use of more sophisticated tools to achieve optimal results consistent within the paradigm of long-term sustainability. Simulation modeling is one such option, thanks to the considerable advancements made in information technology. A simulation model of aerial work was compiled within the presented work, and its functionality was verified using specific examples that confirmed in full the suitability of using simulations in the preparation of aerial work within construction. A detailed analysis of helicopter operations showed that an algorithm that accounts for future weather conditions at the construction site, and specifically focused on the conditions at the given altitude above the ground, should be a dominant feature of simulation models. It is exceptionally important that such data be known within the preparations for aerial work as accurately as possible, and, as such, this article describes the process of obtaining meteorological information for simulation models in detail using a numerical weather forecast and the reliability of data obtained in this manner. Based on the results obtained during this research, the proposed simulation model can be recommended as a suitable tool in the preparation of buildings. Its use is especially important if construction takes place under difficult natural conditions, where work cannot be carried out without the use of helicopters. We perceive the simulation model as a potential tool for digitizing construction preparations in the age of Industry 4.0.
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Sal, Firat. "Variance constrained trajectory tracking for tandem-rotor helicopters." Aircraft Engineering and Aerospace Technology 92, no. 3 (2020): 398–403. http://dx.doi.org/10.1108/aeat-10-2019-0205.
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Purpose This paper aims to present novel results for trajectory tracking of tandem-rotor helicopters via variance-constrained controllers. Design/methodology/approach Regarding these purposes, linearized tandem-rotor helicopter models are benefitted. Findings Variance-constrained controllers are very beneficial for trajectory tracking of tandem-rotor helicopters while there exists variance bounds on outputs of interest. Practical implications Variance-constrained controllers can be used for cheaper tandem-rotor helicopter operations with high trajectory tracking quality. Originality/value Applying variance-constrained control strategy for tandem-rotor helicopters during trajectory tracking. This also causes less fuel consumption and green environment, and good trajectory tracking quality.
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Zhang, Ming, Yu Zhang, Zhifeng Qiu, and Hanlin Wu. "Two-Stage Covering Location Model for Air–Ground Medical Rescue System." Sustainability 11, no. 12 (2019): 3242. http://dx.doi.org/10.3390/su11123242.
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This study tackled the multimodal facility location problem in emergency medical rescue. First, an intermodal setting was suggested, i.e., considering cooperation between ground ambulances and helicopters in emergency medical rescues. Specifically, four scheduling modes were structured: air only, ground only, air-ground combined mode if landing and take-off site for helicopters near the wounded is available, and air-ground transshipment if the landing and take-off site for helicopters near the wounded is not available. Second, a two-stage covering location model was proposed. In the first stage, a set-covering model was developed to achieve maximum coverage and minimal total construction cost of emergency rescue facilities. The optimal mixed allocation proportion of helicopters and ground ambulances was then obtained to guarantee cohesion between the hierarchical models and covering characteristics and the economic efficiency of location results. In the second stage, for given emergency locations, an emergency scheduling mode matrix was constructed for meeting response time and total rescue time constraints. The proposed model obtains optimal results in terms of coverage, construction cost, and rescue time. A case study of Beijing, China validated the feasibility and efficiency of the two-stage covering location model for multimodal emergency medical rescue network. The proposed air-ground rescue system and two-stage covering location model can be extended and also used for large-scale disaster rescue management.
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Нерубасский, Вадим Владимирович. "РЫНОК И ПЕРСПЕКТИВЫ ЛЕГКИХ ВЕРТОЛЕТОВ С ГАЗОТУРБИННЫМИ ДВИГАТЕЛЯМИ". Aerospace technic and technology, № 5 (29 серпня 2020): 5–12. http://dx.doi.org/10.32620/aktt.2020.5.01.
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In the introductory part of the article, it is provided brief information about the main activity of JSC “Element”- developer and manufacturer of electronic control systems for aircraft engines, in particular unit RDTs-450M for AI-450M helicopter turboshaft gas turbine engines, created by SE “Ivchenko-Progress”. JSC ”Element”, together with its partners - SE “Ivchenko-Progress” and JSC “Motor-Sich” – for more than 10 years involved in the modernization of Mi-2 light helicopter.In the next section is gave the classification of helicopters, as well as a segment of light helicopters with turbine engines. It is outlined the scope of light helicopters. It is noted that the segment of light helicopters with turbine engines – the most popular in the world market of civil helicopters and provides a forecast of the supply of these helicopters for the next 10 years.Lists the world's major developers and manufacturers of light helicopters, and the technical characteristics of 12 models of light helicopters with turbine engines are depicted. It is noted that most helicopter models are not entirely new developments and have been modernized over many years. The characteristic design features of light helicopters with turbine engines, especially the layout of plant and equipment are depicted. There is a trend of using one model of helicopter multiple engine types.Lists the world's major developers and manufacturers of engines for light helicopters, as well as the technical characteristics of the six models of gas turbine engines are depicted. The main structural and compositional features of gas-turbine engines of different manufacturers and types of a helicopter on which they installed are described. Separately, brief information about the Ukrainian gas-turbine engines: AI-450M and MS-500V. It is noted that all, without exception, mentioned in the article, engines are equipped with a digital single or dual-channel FADEC type control system with hydro-mechanical redundancy.Brief information about individual conceptual samples of rotary-wing technology introduced in recent years is given. The main directions of work in the field of helicopter engines are described.In conclusion, the Ukrainian helicopter and Aero-engine industry are in a difficult economic situation, but remain competitive and require assistance and the expansion of the market.
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Balakchina, O., and V. Shalenny. "Design organization and construction implementation of the installation and reconstruction technology using helicopters." IOP Conference Series: Materials Science and Engineering 913 (September 12, 2020): 042039. http://dx.doi.org/10.1088/1757-899x/913/4/042039.
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Bieliatynskyi, Andrii, Oleksandra Akmaldinova, and Victoria Akmaldinova. "Vertodrom covering calculation and designing technology." Theory and practice of design, no. 23 (December 17, 2021): 21–30. http://dx.doi.org/10.18372/2415-8151.23.16261.
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The article is devoted to the analysis of existing methods of calculation of rigid heliport coverings, both domestic and foreign. Considerable attention is paid to the geometric dimensions in the plan and layout; location and orientation of heliports. Types of helipads are considered; materials used in the construction of heliports; type of structures (panels), designed for the construction of helicopter pads at the surface level (on any dense surface or ordinary soil), that successfully replace concrete, as well as for the reconstruction of worn and damaged concrete helicopter pads on rooftops and other heliport modifications; possible locations of helicopter pads, which may be different in size and configuration: mobile, off-road, ground, on the roofs of buildings and structures, on pontoons, on sea or river vessels and yachts, on offshore drilling platforms, by individual projects. Approaches to the improvement of the existing method of calculation and design of rigid helipads are analyzed.A comparative analysis of ICAO, FAA, SNiP 2.05.08-85 regulatory documentation and recommendations, which do not provide a clear idea of the method of calculating the thickness of rigid heliports, do not separate the calculation of heliports from the calculation of aerodrome pavements, do not consider any critical cross sections in calculating the load from helicopters and the main differences in designing coverings for helicopters from those for aircraft maintenance, connected with the dynamics of the takeoff and landing operations.As the weight of modern helicopters varies widely, it has been established that different types of coverings must be used for different weight categories (from structures raised above the ground level for light and medium-weight helicopters to cement concrete coverings for heavy helicopters).
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Szafran, Krzysztof, and Marcin Michalczyk. "Various Types of The Rotorcraft Design in the Context of Aerospace Regulations." Transactions on Aerospace Research 2018, no. 1 (2018): 146–53. http://dx.doi.org/10.2478/tar-2018-0010.
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Abstract In the next article on synthesis of regulations, the authors presented the general legal requirements for rotorcraft, which is limited to US regulations, because the vast majority of world regulations are based on them. The Institute of Aviation in Warsaw has developed requirements concerning the construction and operation of rotorcraft in Poland. These requirements constitute an important contribution to the regulations of the Civil Aviation Authority which are in force in the air space of the Republic of Poland. This paper presents the legal situation of rotorcraft and compares the requirements for helicopters and gyroplane. The conclusions highlighted the differences that arise from regulations between helicopters and rotorcraft. The authors have suggested the necessity to separate provisions for the group of windmills, which is implemented in the regulations of the Civil Aviation Authority. The presented work is the second of a planned series of publications in which authors intend to bring some of the issues to the reader about the design aspects of aircraft in selected global aviation regulations.
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Singh, Anvinder, and Varun Sharma. "DESIGN ANALYSIS AND CONSTRUCTION OF ENERGY HARVESTING COAXIAL HELICOPTER." Aviation 17, no. 4 (2013): 145–49. http://dx.doi.org/10.3846/16487788.2013.861230.
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With the growing need for technology, the tendency for errors has increased many times, which often results in loss of human lives. Our main aim of this paper is to show the implementation of a coaxial rotor aerial vehicle that can be controlled by a radio frequency transmitter. The helicopter is capable of manoeuvring in an area where real helicopters cannot. The area could be a flooded region, a place hit by an earthquake, or a building on fire. The main aim is to transmit video of that place to a base station by the camera attached to the helicopter. Various factors required to make a safe and successful coaxial helicopter are discussed and extensive flight testing proves that this flying machine is better in efficiency and performance than a traditional single rotor aerial vehicle. The relation of flight parameters like torque, induced power, rpm, pitch, and total power are discussed. A piezoelectric sensor is used to determine the vibrations occurring in the body so that they can be minimised. A successful attempt to convert the vibrations into a charge by piezoelectric energy harvesters is made.
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Smoak, Robert A., and Xavier R. Ollat. "Construction of control design models from engineering simulation models." Mathematical and Computer Modelling 14 (1990): 413–17. http://dx.doi.org/10.1016/0895-7177(90)90218-c.
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Jing, Fang, Li Ning Tan, Di Wang, and Ting Ting Zhang. "An Attitude Stabilization Method for Quadrotor Helicopter Using Brushless Motors." Applied Mechanics and Materials 427-429 (September 2013): 433–37. http://dx.doi.org/10.4028/www.scientific.net/amm.427-429.433.
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It is an important practical design problem for control system design of quadrotor helicopters with accurately actuator modeling, which is not mentioned in many previous works. In order to improve the performance of attitude stabilization control system, a new strategy is proposed in this paper. This control strategy is based on the accurately nonlinear modeling of the brushless motors using the Hammerstein series models. Furthermore the identification method to obtain such models from observed input-output data is presented. After models of four brushless motor are obtained, a backstepping attitude controller is designed to stabilize the quadrotor helicopter. Flight experiments show that the proposed control strategy can achieve higher performance than past ones.
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Clarkson, P. John, Caroline Simons, and Claudia Eckert. "Predicting Change Propagation in Complex Design." Journal of Mechanical Design 126, no. 5 (2004): 788–97. http://dx.doi.org/10.1115/1.1765117.
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In redesign and design for customization, products are changed. During this process a change to one part of the product will, in most cases, result in changes to other parts. The prediction of such change provides a significant challenge in the management of redesign and customization of complex products where many change propagation paths may be possible. This paper reports on an analysis of change behavior based on a case study in Westland Helicopters of rotorcraft design; the development of mathematical models to predict the risk of change propagation in terms of likelihood and impact of change; and the development of a prototype computer support tool to calculate such information for a specific product. With knowledge of likely change propagation paths and their impact on the delivery of the product, design effort can be directed towards avoiding change to “expensive” sub-systems and, where possible, allowing change where it is easier to implement while still achieving the overall changes required.
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Stenfelt, G., and U. Ringertz. "Design and construction of aeroelastic wind tunnel models." Aeronautical Journal 119, no. 1222 (2015): 1585–99. http://dx.doi.org/10.1017/s0001924000011416.
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AbstractThe design and building of accurately scaled aeroelastic wind-tunnel models is difficult, time consuming and very costly. With the increasing usefulness of computational methods for predicting aeroelastic phenomena, few complex models have been built in recent years. New fighter aircraft projects are also becoming more and more scarce, and transport aircraft have essentially the same configuration since half a decade. This also significantly reduces the need for aeroelastic wind-tunnel models. However, there still is an interest in the results from aeroelastic testing. In some cases new and radical configurations may warrant wind-tunnel testing and in other cases complex phenomena arising in fight testing may need carefully performed experiments to resolve problems. However, there is definitely a trend towards building models and performing testing in the support of the development of computational methods.The developments in computer technology do not only improve the computational methods for aeroelasticity. Modern Computer Aided Design and Manufacturing techniques can significantly improve the quality and efficiency of the design and build process for aeroelastic models. There have also been some recent improvements in measurement techniques which have proven very useful for testing of aeroelastic wind-tunnel models. The paper will present some new design and build techniques developed for the manufacturing of a large scale wind-tunnel model of a canard delta wing fighter aircraft configuration. In the build process fiber-reinforced composites will be used, hence, challenges and possible solutions concerning the ability to produce a model with well defined material properties and fiber angles will be discussed. Further challenges arise when both measurement equipment and adjustable control surfaces should be attached inside the model using techniques that are possible to describe with computational methods. In addition, equipment, such as pressure taps, and control surface mechanics need to fit and function in a flexible structure. As a result, the above requirements will lead to necessary compromises in the design, hence, the paper will present the choices taken during the build process and for which reasons. The use of an optical positioning measurement system will also be discussed for both the validation of model properties and non-contact measurement of model deformations during wind-tunnel testing.
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Huber, Gerald A., Xishun Zhang, and Robin Fontaine. "Superpave Models: Predicting Performance during Design and Construction." Transportation Research Record: Journal of the Transportation Research Board 1545, no. 1 (1996): 105–12. http://dx.doi.org/10.1177/0361198196154500114.
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The Strategic Highway Research Program (SHRP) spent $50 million researching asphalt binders and asphalt mixtures and provided three main products: an asphalt binder specification, an asphalt mixture specification, and Superpave, an asphalt mixture design system that encompasses both the binder and mixture specification. SHRP researchers have provided tools that promise more robust asphalt mixtures with reduced risk of premature failure. Implementation of the specifications and mix design system will require overcoming several obstacles. Superpave must be demonstrated to be practical and easy to use. The impact of Superpave aggregate requirements on aggregate availability must be determined. The Superpave gyratory compaction procedure has been uniquely defined and then calibrated to traffic volume. The reasonableness of this approach must be tested in widespread application. Perhaps the largest implementation hurdle exists in the performance models. Expensive test equipment is necessary to do the performance-based tests. The performance predictions must be established as reasonable to justify the cost. A highway reconstruction project containing three Superpave Level 1 mix designs is documented including quality control done with the Superpave gyratory compactor. Superpave Level 2 performance-based tests were carried out to predict permanent deformation of the design and the mixture as constructed. The performance-based engineering properties obtained from the tests are evaluated, and the reasonableness of the performance prediction models is discussed.
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Margolin, L. G., and W. J. Rider. "The design and construction of implicit LES models." International Journal for Numerical Methods in Fluids 47, no. 10-11 (2005): 1173–79. http://dx.doi.org/10.1002/fld.862.
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Hu, Bin, Xingyuan Chen, and Songchen Han. "Helicopter Takeoff and Landing Point Location in Cities for Emergency Services." Applied Sciences 12, no. 19 (2022): 9570. http://dx.doi.org/10.3390/app12199570.
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In low-altitude rescue, civilian helicopters, relying on their speed, efficiency and flexibility, play at center stage. Due to the terrain restrictions of the disaster area, it is difficult for helicopters to carry out safe and efficient rescue in cities. In order to facilitate emergency rescue, fixed helicopter takeoff and landing points for rescue missions must be selected strategically and wisely. However, the traditional method is to analyze the satellite data and conduct field surveys manually, which is rather subjective. A scientific, simple and efficient method of location selection is in urgent need. This paper analyzes the normativeness of the location of the helicopter’s take-off and landing point and establishes a model of the slope and undulation of the landing site. It utilizes ArcGIS software to build layers and selects for the terrain element models that meet the specifications. It also studies the rescue radius commonly used in the world and then maximizes the location range of the take-off and landing point based on the greedy algorithm. Considering the construction cost, the final optimized site selection result is obtained. The results show that the use of GIS space technology can effectively select suitable take-off and landing points and gain valuable time for low-altitude rescue.
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Kutt, Filip, Krzysztof Blecharz, and Dariusz Karkosiński. "Axial-Flux Permanent-Magnet Dual-Rotor Generator for a Counter-Rotating Wind Turbine." Energies 13, no. 11 (2020): 2833. http://dx.doi.org/10.3390/en13112833.
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Coaxial counter-rotating propellers have been widely applied in ships and helicopters for improving the propulsion efficiency and offsetting system reactive torques. Lately, the counter-rotating concept has been introduced into the wind turbine design. Distributed wind power generation systems often require a novel approach in generator design. In this paper, prototype development of axial-flux generator with a counter-rotating field and armature is presented. The design process was composed of three main steps: analytical calculation, FEM simulation and prototype experimental measurements. The key aspect in the prototype development was the mechanical construction of two rotating components of the generator. Sturdy construction was achieved using two points of contact between both rotors via the placement of the bearing between the inner and outer rotor. The experimental analysis of the prototype generator has been conducted in the laboratory at the dynamometer test stand equipped with a torque sensor. The general premise for the development of such a machine was an investigation into the possibility of developing a dual rotor wind turbine. The proposed solution had to meet certain criteria such as relatively simple construction of the generator and the direct coupling between the generator and the wind turbines. The simple construction and the lack of any gearbox would allow for such a system to be constructed relatively cheaply, which is a key aspect in further system development.
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Yik, Francis W. H., and Vincent K. C. Lam. "Chiller models for plant design studies." Building Services Engineering Research and Technology 19, no. 4 (1998): 233–41. http://dx.doi.org/10.1177/014362449801900407.
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Khemlani, Lachmi. "Building Product Models: Computer Environments Supporting Design and Construction." Automation in Construction 11, no. 4 (2002): 495–96. http://dx.doi.org/10.1016/s0926-5805(01)00082-6.
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Lenz, Gerold, Alexander Poisel, Markus Brandtner, Andreas Goricki, and Oliver K. Wagner. "Semmering Base Tunnel - Geotechnical models in design and construction." Geomechanics and Tunnelling 11, no. 5 (2018): 559–65. http://dx.doi.org/10.1002/geot.201800028.
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Nannoni, Fabio. "Invited Paper: Rotorcraft Design: The Crucial Influence of Safety from Concept to Fleet Support The 41st Alexander A. Nikolsky Honorary Lecture." Journal of the American Helicopter Society 67, no. 2 (2022): 1–19. http://dx.doi.org/10.4050/jahs.67.021001.
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It is an immense honor to have been selected to hold the prestigious 41st Nikolsky Lecture and to have the opportunity to synthesize my experiences with regards to the most important principle that permeates aeronautical engineering—"the concept of safety." Having worked in the rotary-wing field for 39 years, with growing levels of involvement and responsibilities, I have been involved in the design, development, and certification of many helicopter models at the Leonardo Helicopters Division (LHD; formerly Agusta and then AgustaWestland), such as A109, A119, EH101, A129, NH90, AW609. More recently, I had the full responsibility of design, development, certification, and entry into service of three new helicopter types within the "AW Family concept", specifically the AW139, AW189, and AW169. I am profoundly grateful for the mentors encountered in my professional life—Bruno Lovera and Santino Pancotti, both of whom were also honored with the Nikolsky Lectureship. In working with them, not a single day passed where the word "safety" was not mentioned. They taught me that "safety" shall be the mantra of every aeronautical engineer because it is our principal duty and responsibility, towards those who travel in, work on, and work with our products and entrust their lives to our work and professionalism daily. I have tried hard never to forget this lesson, and to convey this to the young engineers that I have had the chance and pleasure to work with. If I have been able to pass on this lesson successfully, through my work with others through this lectureship, it would be the greatest achievement of my life. In this vein, this paper is organized in three parts: (i) definitions and principles, along with some "philosophical" concepts; (ii) the application of these principles at Leonardo in the design of the latest generation of helicopters, and finally (iii) a discussion of emerging "safety technologies" that promise to improve the safety of future helicopters and operations.
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Guner, Feyyaz, and J. V. R. Prasad. "Combined Momentum Theory and Simple Vortex Theory Inflow Model for Multirotor Configurations." Journal of the American Helicopter Society 67, no. 2 (2022): 1–15. http://dx.doi.org/10.4050/jahs.67.022007.
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For conventional main/tail rotor helicopters, momentum theory-based inflow models are still popular for design trade studies and flight simulations. However, simple momentum theory-based inflow models are not readily applicable in design trade studies of multirotor configuration vehicles where complex flow interactions among rotors can have a significant impact on vehicle overall performance, and hence, can impact vehicle sizing. The use of empirically corrected ad hoc inflow models is not often satisfactory. In this study, momentum theory is combined with a simple vortex theory in the development of a combined momentum theory and simple vortex theory (CMTSVT) based inflow model that is readily applicable to generic multirotor configurations. The developed model is validated against some multirotor inflow models and experimental data from the literature through comparisons of inflow predictions and performance predictions for different dual-rotor configurations. Further, inflow predictions using the proposed inflow model for a partially overlapping quad-rotor configuration are presented to illustrate the significance of rotor-on-rotor flow interactions in multirotor vehicle configurations.
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Sarker, Bhaba R., Pius J. Egbelu, T. Warren Liao, and Junfang Yu. "Planning and design models for construction industry: A critical survey." Automation in Construction 22 (March 2012): 123–34. http://dx.doi.org/10.1016/j.autcon.2011.09.011.
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Puri, Nisha, and Yelda Turkan. "Bridge construction progress monitoring using lidar and 4D design models." Automation in Construction 109 (January 2020): 102961. http://dx.doi.org/10.1016/j.autcon.2019.102961.
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Gameiro, Marcio, Tomáš Gedeon, Shane Kepley, and Konstantin Mischaikow. "Rational design of complex phenotype via network models." PLOS Computational Biology 17, no. 7 (2021): e1009189. http://dx.doi.org/10.1371/journal.pcbi.1009189.
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We demonstrate a modeling and computational framework that allows for rapid screening of thousands of potential network designs for particular dynamic behavior. To illustrate this capability we consider the problem of hysteresis, a prerequisite for construction of robust bistable switches and hence a cornerstone for construction of more complex synthetic circuits. We evaluate and rank most three node networks according to their ability to robustly exhibit hysteresis where robustness is measured with respect to parameters over multiple dynamic phenotypes. Focusing on the highest ranked networks, we demonstrate how additional robustness and design constraints can be applied. We compare our results to more traditional methods based on specific parameterization of ordinary differential equation models and demonstrate a strong qualitative match at a small fraction of the computational cost.
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Lomas, K. J., D. P. Bloomfield, A. Cole, F. Parand, and A. A. Pinney. "Dynamic thermal models: Reliability for domestic building design." Building Services Engineering Research and Technology 12, no. 4 (1991): 115–28. http://dx.doi.org/10.1177/014362449101200401.
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Picanço Cruz, Eduardo, Carlos Navarro Fontanillas, Karen Possoli, and Martius Vicente Rodriguez y Rodriguez. "Association of Borda's method and analytic hierarchy process (AHP) for the acquisition of helicopters by the Brazilian Navy." Revista Gestão da Produção Operações e Sistemas 15, no. 4 (2020): 23–47. http://dx.doi.org/10.15675/gepros.v15i4.2432.
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Purpose – A combination of the Analytic Hierarchy Process (AHP) and the Borda’s Method as a suggestion for collective decision-making. By harmonizing the cardinal scale, resulting from the AHP, with the Borda’s Method, it is expected that the evaluations of the alternatives for new helicopters maximize the individual opinions in the construction of a collective decision. Design/methodology/approach – Qualitative and quantitative. The agents involved in the project of acquisition of helicopters for General Usage and Small Capacity for the Brazilian Navy were interviewed, ten pilots and six military engineers from Aeronautics Board of the Brazilian Navy in Rio de Janeiro. The data were treated by combining the cardinal scale resulting from the AHP with the method proposed by Borda. Findings – Analyzing the MGP’s obtained by AHP, it was possible to ascertain that judgment inconsistencies did not affect the result. It is considered that both methods are capable to promote a helpful decision aid inside the BN in the decision upon the purchase of an aircraft to substitute and enhance their naval aviation fleet. It is also considered that both methods can be applied in similar situation of decisions between mutually exclusive alternatives. Originality/value – The usage of hybrid decision aids (created by the combination of methods) in a multicriteria analysis helps organizations make the best use of available resources, especially in complex decision scenarios. This study helps decision-makers to reflect about the process’ tolerance limits. Keywords - Collective decisions; Multicriteria; Borda's Method; Analytic Hierarchy Process.
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Morris, Robert, K. Venable, Marco Pegoraro, and James Lindsey. "Local Search for Designing Noise-Minimal Rotorcraft Approach Trajectorie." Proceedings of the AAAI Conference on Artificial Intelligence 26, no. 2 (2012): 2311–16. http://dx.doi.org/10.1609/aaai.v26i2.18976.
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NASA and the international community are investing in the development of a commercial transportation infrastructure that includes the increased use of rotorcraft, specifically helicopters and civil tilt rotors. However, there is significant concern over the impact of noise on the communities surrounding the transportation facilities. One way to address the rotorcraft noise problem is by exploiting powerful search techniques coming from artificial intelligence coupled with simulation and field tests to design low-noise flight profiles which can be tested in simulation or through field tests. This paper investigates the use of simulation based on predictive physical models to facilitate the search for low-noise trajectories using local search combined with a robust noise simulator.
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Chen, Wei Tong. "Design Satisfaction Measurement." International Journal of Information Technology Project Management 4, no. 2 (2013): 75–91. http://dx.doi.org/10.4018/jitpm.2013040105.
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This study presents a novel model for evaluating design satisfaction (DS) for primary school construction projects. The proposed model consists of three aspects including Teaching space design, Campus planning and design, and Eco-awareness oriented and 19 DS evaluation items (DSEIs). Eco-awareness oriented was the most important aspect and must be exerted during the design phase of school construction based on the DS evaluation results of 10 schools. Additionally, special attention should be paid to design of natural lighting in classroom (DSEI5), utilization of color in classroom (DSEI7) and construction scheduling and planning (DSEI11) as they are important DSEIs that received low satisfaction scores. The results of this study contribute to the efforts to improve DS and the quality of primary school construction. The framework, methodology, and analytical tools used in the study can be applied to build similar models for other aspects of construction and service performance for school construction projects.
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Ahmadu, Hassan Adaviriku, Yahaya Makarfi Ibrahim, Ahmed Doko Ibrahim, and Muhammed Abdullahi. "Modelling building construction durations." Journal of Financial Management of Property and Construction 20, no. 1 (2015): 65–84. http://dx.doi.org/10.1108/jfmpc-02-2014-0004.
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Purpose – This paper aims to develop a multivariate model that will be applicable to the Nigeria construction industry. Design/methodology/approach – A self-administered questionnaire survey was used to source information on project scope factors and qualitative factors considered in the study. Principal component regression was used for data analysis and model development, using SPSS 16.0 for windows, while T-test was used for model testing and validation. Findings – The study found that delay in progress payment by owner, lateness in revising and approving design document by owner, delay in delivering the site to the contractor by the owner, change order by owner during construction, complexity of project design, poor site management and supervision by contractors, and rain effect on construction activities are qualitative/non-project scope factors with good predictive abilities. Research limitations/implications – Cost, gross floor area and number of floors were the only quantitative/project scope factors considered in the study. The developed models therefore do not account for any variation in duration which may arise from other project scope factors, such as location, procurement route and type of contract. Originality/value – The qualitative factors which emerged as predictors in the derived models increased the accuracy of the models. The models developed therefore serve as useful construction time prediction tools for both consultancy firms and contractor organizations in the Nigerian construction industry.
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Brown, Laura Alexandra, and Manuel Cresciani. "Adaptable design in Olympic construction." International Journal of Building Pathology and Adaptation 35, no. 4 (2017): 397–416. http://dx.doi.org/10.1108/ijbpa-12-2016-0030.
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Purpose The Olympic Games is the largest sporting mega event of its type, with deep cultural and historical roots. The event is short lived compared to the lifespan of the infrastructure required in host cities. The purpose of this paper is to examine models of adaptability in Olympic construction, using case studies in previous Olympic host cities of the Summer Olympic Games (Rome 1960, London 2012), to assess the impact of adaptability on future legacy. Design/methodology/approach A mixed methods approach (archival research, direct observation), was used in two case studies: Rome (Palazzetto dello Sport, Palazzo dello Sport), and London (London Olympic Velodrome, London Aquatics Centre). The case studies examined how adaptability was used in design to secure legacy. Findings In the selected case studies (Rome 1960, London 2012), adaptability has had a positive impact on the post-Games use of venues, all four of which remain in use today. However, there are multiple factors that contribute to post-Games legacy, and further research is necessary. Research limitations/implications Whilst some positive results were observed in this study, more research is necessary across a broader spectrum of sites and venues to make conclusive recommendations for architects designing for Mega Sporting events. Social implications The significance of this study to architectural practice, academia, and society is its potential to benefit future Olympic Games, International Olympic Committee policy, and be extended to other Mega Sporting events. Originality/value The originality of this research lies within its analysis of Olympic infrastructures and sustainability, of which there is a current lack of comparative studies in academic research.
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Flórez-Ruiz, Juan Fernando, Jorge Guillermo Díaz-Rodríguez, Alexander Ramírez-Dueñes, and Félix Antonio Pérez-Rondón. "Design, simulation and construction of a pellets transportation laboratory." ITECKNE 16, no. 2 (2019): 7–17. http://dx.doi.org/10.15332/iteckne.v16i2.2352.
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The article presents how three scaled down industrial machinery models were designed and built as an educational tool to present the transport of particulate material. The literature review showed calculation models for equipment at industrial level, not for laboratory level. There were chosen the most representative means of commercial transport for particulate materials: a conveyor screw, a conveyor belt and a bucket elevator. These three machines were calculated and built in polycarbonate to allow visualization of their internal functioning. The three devices are controlled by a programmable logic controller (PLC) and connected to each other by a SCADA network. The equipment is modular so as not to alter the order of operation, being able to obtain different work sequences. In addition, a man-machine graphic interface (HMI) was developed to supervise and to control the designed equipment. The results of particulate material mass flow obtained are approximately coincident with those estimated, validating the use of calculation models for much lower levels of work. Finally, it is emphasized that the system obtained is an environment for students to implement control techniques using the sensors and motors used in the designs.
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Jung, Eui S., and Dongseok Kang. "Construction of a Knowledge Base for Ergonomic Design with Human Models." Proceedings of the Human Factors and Ergonomics Society Annual Meeting 44, no. 38 (2000): 711–14. http://dx.doi.org/10.1177/154193120004403807.
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In order to economically evaluate products and workplaces from the early stage of design, it is essential to provide the designer with a variety of design and evaluation means. In Korea, incorporation of ergonomic design and evaluation into the computer-aided design process of product development in industry has been in great need. A number of ergonomic design models have been developed and are currently in use. Evaluation functions embedded in those models are, however, based mostly on predictive algorithms such as reach and visibility tests, whereas numerous ergonomic guidelines which constitute a major part of design knowledge have been rarely accommodated to such models. In this research, a knowledge base was constructed to expand the scope of ergonomic evaluation being made through those models. First, a new framework based on an object-oriented database for the model was suggested from the developer's standpoint. Second, the knowledge modeling was done based on the definition through the object-oriented database. Finally, the knowledge base was implemented in the prototype design model that enables to evaluate design alternatives, interactively. It is expected that the knowledge base proposed would lessen the burden of designers through efficient evaluations from the early stage of design.
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Woksepp, Stefan, and Thomas Olofsson. "Credibility and applicability of virtual reality models in design and construction." Advanced Engineering Informatics 22, no. 4 (2008): 520–28. http://dx.doi.org/10.1016/j.aei.2008.06.007.
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Wang, Haoqing, Wen Yi, and Yannick Liu. "Optimal Route Design for Construction Waste Transportation Systems: Mathematical Models and Solution Algorithms." Mathematics 10, no. 22 (2022): 4340. http://dx.doi.org/10.3390/math10224340.
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A huge amount of construction waste is generated in construction sites every day that needs to be transported by vehicle to disposal facilities for processing. Unlike in most typical transportation problems, once these vehicles are loaded with construction waste, they must travel directly to the disposal facility. Moreover, there are different types of construction waste that may require handling by different disposal facilities. In this paper, we develop a model and algorithm for identifying the optimal transportation routes specific to construction waste transportation. Our results can not only minimize the overall costs for both the logistics company and the contractor but also minimize the distance traveled, thus reducing urban traffic emissions.
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M. P., Iwundu,. "Construction of Modified Central Composite Designs for Non-standard Models." International Journal of Statistics and Probability 7, no. 5 (2018): 95. http://dx.doi.org/10.5539/ijsp.v7n5p95.
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The use of loss function in studying the reduction in determinant of information matrix due to missing observations has effectively produced designs that are robust to missing observations. Modified central composite designs are constructed for non-standard models using principles of the loss function or equivalently first compound of (I ) matrix associated with hat matrix . Although central composite designs (CCDs) are reasonably robust to model mis-specifications, efficient designs with fewer design points are more economical. By classifying the losses due to missing design points in the CCD portions, where there are multiple losses associated with specified CCD portions, the design points having less influence may be deleted from the full CCD. This leads to a possible increase in design efficiency and offers alternative designs, similar in the structure of CCDs, for non-standard models.