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Numerical estimation of blade displacement due to air excitation
Mekhalfia, Mohammed Lamine; Procházka, Pavel; Tchawou Tchuisseu, Eder Batista; Hodboď, Robert; Maturkanič, Dušan
2021 - anglický
For the last few years, vibration measurement has taken an intense interest from research activities. For this reason, this article considers, besides vibration measurements, the impact of air forced excitation on blade motion, displacement and vibration through both simulation analysis and The Transformation of mathematical analysis that explain the interaction between fluid (Air) and the structure (Blade) into numerical setup along with FEM analysis through ANSYS Software. 3D Blade was created to meet the same characteristics of the real blade to enable real environment criteria for the simulation.
Klíčová slova:
displacement; Fluid structure interaction (FSI); air; blade
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Numerical estimation of blade displacement due to air excitation
For the last few years, vibration measurement has taken an intense interest from research activities. For this reason, this article considers, besides vibration measurements, the impact of air forced ...
Study of aeroacoustics noise of high-speed aircraft propellers and mitigation of the cause
Prasad, Chandra Shekhar
2021 - anglický
The project deals with the study of aeroacoustics noise generated by high-speed turboprop propellers and methods to minimize its causes. A reduced order flow solver with aeroacaustic noise capturing characteristics is developed for fast numerical analysis purpose. The acoustical performance will be also studied using flow visualization using article image velocimetry under rotation and acoustics noise will be measured by microphones for both conventional as well as unconventional propeller designs at diferent rotational speeds.
Klíčová slova:
aeroacoustics; aircraft propellers; tip-vortex interaction; low noise propeller; ROM-CFD/CAA
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Study of aeroacoustics noise of high-speed aircraft propellers and mitigation of the cause
The project deals with the study of aeroacoustics noise generated by high-speed turboprop propellers and methods to minimize its causes. A reduced order flow solver with aeroacaustic noise capturing ...
Dynamics of Machines and Mechanical Systems with Interactions, DYMAMESI 2021
Zolotarev, Igor; Pešek, Luděk; Kozień, M. S.
2021 - anglický
The aim of the DYMAMESI is to facilitate the exchange of up to date information and knowledge among specialists in structural and multibody dynamics, in coupled interacting systems as aero-elasticity, hydro-elasticity, biomechanics, systems with feedbacks and mechatronics. The colloquium DYMAMESI 2021 is cofunded by the Strategy AV21 initiative of the Czech Academy of Sciences of the Czech Republic, and in 2021 will be hosted by Cracow University of Technology, Institute of Applied Mechanics, Section of Dynamics of Systems.
Klíčová slova:
dynamics; vibrations of mechanical systems; vibrodiagnostics; energy transformations
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Dynamics of Machines and Mechanical Systems with Interactions, DYMAMESI 2021
The aim of the DYMAMESI is to facilitate the exchange of up to date information and knowledge among specialists in structural and multibody dynamics, in coupled interacting systems as aero-elasticity, ...
The new HPC results of 3D FE modelling of dry-friction damping at tie-boss couplings of bladed wheel - 6nd resonant mode
Pešek, Luděk; Šnábl, Pavel; Bula, Vítězslav
2021 - anglický
The paper is a direct continuation of our study published in the last colloquium DYMAMESI. This paper deals with the new results of dry-friction damping calculation of the bladed wheel with tie-boss couplings vibrating at a higher resonant mode, i.e. mode with 6 nodal diameters (ND). The numerical solution of the wheel based on 3D finite element method with surface-to-surface dry friction contact model is applied. Due to dry friction contacts and non-linear solution, it leads to HPC computations and long computation times. Therefore, the earlier proposed computational strategy for damping evaluation where the resonant attenuation is computed directly from the defined resonant initial conditions given by the 6ND mode is used. Comparison of experimental and numerical results of dynamical behaviour of the bladed wheel yields a reasonable agreement for the studied vibration mode.
Klíčová slova:
bladed wheel; dry-friction contacts; damping; tie-boss couplings
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
The new HPC results of 3D FE modelling of dry-friction damping at tie-boss couplings of bladed wheel - 6nd resonant mode
The paper is a direct continuation of our study published in the last colloquium DYMAMESI. This paper deals with the new results of dry-friction damping calculation of the bladed wheel with tie-boss ...
Verification of our deformation member for measuring axial force under torsional dynamic load
Šulc, Petr; Pešek, Luděk; Štěpánek, Ivo; Šnábl, Pavel; Bula, Vítězslav
2021 - anglický
This paper deals with experimental testing of hard rubbers under torsional harmonic loading on an axial torsional servohydraulic testing machine Instron 8852. In evaluating these experiments, we focused on obtaining axial forces and elongation, which is a confirmation of the so-called Poynting effect under torsional loading. An important result from these experiments is a comparison of axial forces from this device with the results from our designed and assembled torsion device with a deformation member for measuring axial forces, which brings us some verification of this device.
Klíčová slova:
axial force; torsion dynamic load; hard rubber; Poynting effect
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Verification of our deformation member for measuring axial force under torsional dynamic load
This paper deals with experimental testing of hard rubbers under torsional harmonic loading on an axial torsional servohydraulic testing machine Instron 8852. In evaluating these experiments, we ...
Numerical simulation of dynamic loading of a test blade in forced torsional vibration
Šidlof, P.; Vomáčko, V.; Lepičovský, Jan; Šimurda, David; Štěpán, M.; Luxa, Martin
2021 - anglický
Within a new project focused on blade flutter research, building on previous experience with the NASA Transonic Flutter Cascade facility, static blade cascade and airfoil flutter experiments realized in cooperation between the Institute of Thermomechanics and Technical University of Liberec, a new test facility is under development for the investigation of high subsonic and transonic flow in a blade cascade under forced torsional oscillation. Apart from aerodynamic loading of the blades, the oscillating blade will be exposed to significant structural stresses due to the highfrequency torsional vibration. In order to avoid structural integrity issues from high-cycle fatigue, a numerical simulation of the stress and displacement of the blade was realized. Regions where equivalent stress reaches maximum values were identified, and elastic deformations were computed. The limits in oscillation amplitude and frequency for the safe operation of the experimental setup were discussed.
Klíčová slova:
blade flutter; structural analysis; torsional vibration
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Numerical simulation of dynamic loading of a test blade in forced torsional vibration
Within a new project focused on blade flutter research, building on previous experience with the NASA Transonic Flutter Cascade facility, static blade cascade and airfoil flutter experiments realized ...
Návrh kompresorové mříže KOBRA
Fiala, Petr; Luxa, Martin; Šimurda, David
2021 - český
Prismatická profilová mříž má vyprojektovánu drenáž pro měření statických tlaků na profilech, které ohraničují její střední mezilopatkový kanál. Bočnice modelu jsou opatřeny sloty pro odsávání mezní vrstvy. Prismatic profile cascade has static pressure taps on suction and pressure side of profiles, which form the interblade channel in the middle of the cascade. The sidewalls of the cascade are equipped with slots for boundary layer control.
Klíčová slova:
compressor cascade; axial compressor; aerodynamic experiments; AVDR
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Návrh kompresorové mříže KOBRA
Prismatická profilová mříž má vyprojektovánu drenáž pro měření statických tlaků na profilech, které ohraničují její střední mezilopatkový kanál. Bočnice modelu jsou opatřeny sloty pro odsávání mezní ...
Identifikace materiálových konstant nových pryží tlumících segmentů z modální analýzy železničního pryží odpruženého kola
Šulc, Petr; Pešek, Luděk; Šnábl, Pavel; Bula, Vítězslav
2021 - český
Cílem modální analýzy bylo porovnat a identifikovat materiálové konstanty dvou navržených směsí pryžových tlumících segmentů železničního kola. Modální analýza byla řešena ve dvou etapách, a to experimentálně a následně numericky. Experimentální modální analýza probíhala v laboratoři ÚT s použitím jednobodového buzení (SIMO) na gumo-odpruženém kole, a to pro obě navržené varianty pryžových segmentů s označením 42809 a 46809. Z této dynamické analýzy byly získány vlastní frekvence a tvary kmitání kola v pásmu do 6,5kHz. Materiálové konstanty pryže byly získány na základě ladění materiálových parametrů pryžových segmentů, tj. modulu pružnosti a koeficientu speciálního modelu proporcionální tlumení, 3D MKP modelu železničního kola na hodnoty vlastních frekvencí a poměrných útlumů vybraných tvarů vlastního kmitání kol. The aim of the modal analysis was to compare and identify the material constants of two proposed mixtures of rubber damping segments of a railway wheel. The modal analysis was carried out in two stages, experimentally and then numerically. The experimental modal analysis was carried on a rubber-suspension wheel for the two proposed rubber types of segment , designated 42809 and 46809. From this dynamic analysis, the natural frequencies and eignemodes of the wheel oscillations were obtained in the frequency bandwidth up to 6.5kHz. The material constants of the rubber were obtained by tuning the material parameters of the rubber segments, i.e. elastic modulus and special proportional damping coefficient, of the 3D FEM model of the railway wheel to the values of natural frequencies and damping ratios of the selected wheel natural vibration modes.
Klíčová slova:
material constants; rubber; railway wheels; damping
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Identifikace materiálových konstant nových pryží tlumících segmentů z modální analýzy železničního pryží odpruženého kola
Cílem modální analýzy bylo porovnat a identifikovat materiálové konstanty dvou navržených směsí pryžových tlumících segmentů železničního kola. Modální analýza byla řešena ve dvou etapách, a to ...
A simple algorithm for probes positioning in BTT systems
Tchawou Tchuisseu, Eder Batista; Procházka, Pavel; Maturkanič, Dušan
2020 - anglický
The Blade Tip Timing (BTT), a non-contact method for measuring the blade tip displacement through the time of arrival, is studied in this article. This work proposes a simple algorithm based on the minimization of the coherence and the condition number of the sensingmatrix for defining the best probe positioning in the case of synchronous and asynchronous vibrations.
Klíčová slova:
BTT systems; probe positioning; condition number; coherence
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
A simple algorithm for probes positioning in BTT systems
The Blade Tip Timing (BTT), a non-contact method for measuring the blade tip displacement through the time of arrival, is studied in this article. This work proposes a simple algorithm based on the ...
Contribution to HPC FEM calculations of bladed disk dynamics with dry-friction contacts
Pešek, Luděk; Šnábl, Pavel; Bula, Vítězslav
2020 - anglický
The experimental set-up for studying dynamical behaviour of the bladed wheel with pre-stressed dry-friction contacts in tie-bosses was built. The numerical solution of the turbine bladed wheel with tie-bosses based on 3D finite element method with surface to surface dry-friction contact model is proposed. Comparison of experimental and preliminary numerical results of dynamical behaviour and damping estimation of our bladed wheel design yielded a reasonable agreement. Due to dry-friction contacts and non-linear solution of 3D FE model it, however, leads to HPC computations and long computation times. The contribution deals with description of computational strategy for damping evaluation and achieved results, too.
Klíčová slova:
bladed wheel; dry-friction contacts; damping; tie-boss couplings
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Contribution to HPC FEM calculations of bladed disk dynamics with dry-friction contacts
The experimental set-up for studying dynamical behaviour of the bladed wheel with pre-stressed dry-friction contacts in tie-bosses was built. The numerical solution of the turbine bladed wheel with ...
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