Temat: blade deformation - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Simulation investigation of rotor loads and blade deformations in steady states and at boundaries of helicopter flight envelope
Autorzy:: Stanisławski, J.
Powiązania:: https://bibliotekanauki.pl/articles/246484.pdf
Data publikacji:: 2017
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: helicopter
rotor loads
blade deformation
Opis:: Results of calculation of the helicopter main rotor loads and deformations of rotor blades are presented. The simulations concern level flight states and cases of boundary flight envelope such as wind gust, dive recovery and pull-up manoeuvre. The calculations were performed for data of the three-bladed articulated rotor of light helicopter. The method of analysis assumes modelling the rotor blades as elastic axes with sets of lumped masses of blade segments distributed along radius of blade. The model of deformable blade allows flap, lead-lag and pitch motion of blade including effects of out-of-plane bending, in-plane bending and torsion due to aerodynamic and inertial forces and moments acting on the blade. Equations of motion of rotor blades are solved applying Runge-Kutta method. Parameters of blade motion, according to Galerkin method, are considered as a combination of assumed torsion and bending eigen modes of the rotor blade. The rotor loads, in all considered cases of flight states, are calculated for quasi-steady conditions assuming the constant value of the following parameters: rotor rotational speed, position of the main rotor axis in air and position of swashplate due to rotor axis which defines the collective and cyclic control pitch angle of blades. The results of calculations of rotor loads and blade deflections are presented in form of timeruns and as distributions on rotor disk due to blade elements radial and azimuthal positions. The simulation investigation may help to collect data for prediction the fatigue strength of blade applying results for steady flight states and for definition the extreme loads for boundaries of helicopter flight envelope.
Źródło:: Journal of KONES; 2017, 24, 2; 239-246
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Performance requirements and simulation of rotor operation for high-mountain rescue helicopter
Autorzy:: Stanisławski, J.
Powiązania:: https://bibliotekanauki.pl/articles/243448.pdf
Data publikacji:: 2018
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: rescue helicopter
high-mountain operations
rotor blade deformation
Opis:: Simulation results concerning performance of helicopter suitable for high-mountain rescue operations are presented. Including operations in regions of the highest Himalaya Mountains, the possibility of hover ceiling out of ground effect (OGE) at 10,000 m above sea level is assumed. Demand of high ratio of developed lift to power required for hover leads to choice the coaxial rotor configuration as the best for rescue helicopter, which can operate in extremely high mountain environment, and gives good stability features in wind gust conditions in comparison with single main rotor helicopter. For performance calculations the simple model of helicopter is applied, which consists of fuselage point mass and rotor disk. The cases of partial and total power loss are considered to define range of H-V zones and possibilities of flight continuation due to height of landing surface over level of sea. The rotor blades and rotor loads are calculated applying detail model of elastic blade, which includes effects of its deflections due to out-of-plane bending, in plane bending, and torsion. The Runge-Kutta method is applied to solve equations of motion of rotor blades with taken into account effects of blade pitch control and variable deflections of blades. According to Galerkin method, the blade parameters of motion are treated as a combination of torsion and bending eigen modes of the rotor blades. Elastic blade model allows defining behaviour rotor blades in selected states of flight: hover, level flight, wind gust conditions, and pull-up manoeuvre. The results of simulation for upper and lower rotor for blade deflections and loads are shown in form of time-run plots and rotor disk distributions. The simulation investigation may be applied to define features of helicopter configuration suitable for operation in extremely high mountain conditions..
Źródło:: Journal of KONES; 2018, 25, 2; 341-348
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Simulation investigation of operational conditions of rotor for high-speed compound helicopter
Autorzy:: Stanisławski, J.
Powiązania:: https://bibliotekanauki.pl/articles/245640.pdf
Data publikacji:: 2018
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: compound helicopter
rotor loads
blade deformation
helikopter
obciążenia wirnika
deformacja ostrza
Opis:: The article presents results of simulations concerning possibilities of rotorcraft performance enhancements for compound helicopters with introduced additional wings and propellers. The simple model of helicopter including a point mass of fuselage and a rotor treated as a disk was used for calculations of helicopter flight equilibrium conditions. For the defined flight states, the more detailed model of elastic blade was applied to compute magnitude of rotor loads and level of blade deformations. The model of elastic blade includes out-of-plane bending, in plane bending, and torsion effects due to variable aerodynamic and inertial loads of rotor blades. Equations of motion of rotor blades are solved applying Runge-Kutta method. Taking into account Galerkin method, parameters of blade motion are computed as a combination of assumed torsion and bending Eigen modes of the rotor blade. The six-bladed rotor with stiff connections of blades and hub was applied for comparison of flight envelope for conventional helicopter and versions of compound rotorcraft with additional propellers and with wings and propellers. Simulations indicate that, in the case of compound helicopter configuration, achieving the operational flight conditions at high speed of 400 km/h is possible without generating excessive loads and blade deformations. The results of calculations of rotor loads and generated blade deflections are presented in form of time-run plots and as rotor disk distributions, which depend on radial and azimuthal positions of blade elements. The simulation Keywords: compound helicopter, rotor loads, blade deformation 1.Introduction For classical configuration of helicopter, with main rotor and anti-torque tail rotor, the speed of flight is limited in comparison to fixed wing aircraft. The maximum speed of conventional helicopter is restricted due to high drag associated with compressibility effects for advancing rotor blade and stall phenomenon, which occurs at retreating blade zone. A compound helicopter configuration with added lifting wings and separate source of thrust for propulsion may help to unload main rotor and enhance speed range of rotorcraft. Initial development programs of compound helicopters [6], such as the Bell 533, the Lockheed XH-51A fitted with wings and additional turbojet engines, or the Lockheed AH-56A Cheyenne with wings and pushing propeller and after flight tests were not passed to serial production. Emerging demands for improved performance and progress in composite materials and aerodynamics of rotor blades gave impulse to return to compound helicopter concept. In the last decade, the new experimental compound helicopters with additional propulsion were tested [3]: the American Piasecki X-49 Speedhawk, the Sikorsky X2 and the French Eurocopter X3. It should be mentioned that the Eurocopter X3 achieved speed of 472 km/h setting an unofficial speed record for propeller helicopters. Analytical and experimental researchworks were performed to examine features of compound helicopters, which included effects of varying main rotor tip speed [1], wing-rotor lift share [7, 8] and investigation of dynamic stability characteristics [2]. Basing on collected experiences, the next generation of operational compound helicopter designs are being developed. The American Sikorsky S-97 Raider made the maiden flight in 2015 [4] and the European Airbus Helicopter Racer’s configuration was revealed in 2017 [5]. investigation may help to define demands for rotor of high-speed helicopter.
Źródło:: Journal of KONES; 2018, 25, 1; 363-370
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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