Wyniki wyszukiwania - BazTech

1

Methods of modern aircraft aeroelastic analyses in the institute of aviation

Chajec W.

Journal of KONES

|

2018

|

Vol. 25, No. 4

33--42

EN

The aeroelastic phenomena analysis methods used in the Institute of Aviation for aircraft, excluding helicopters, are presented in the article. In industrial practice, a typical approach to those analyses is a linear approach and flutter computation in the frequency domain based on normal modes, including rigid body modes and control system modes. They are determined by means of the finite element method (FEM) model of structure or a result of ground vibration test (GVT). In the GVT case, relatively great vibration amplitudes are applied for a good examination of a not truly linear structure. Instead or apart from the measure of generalized masses, a very theoretical model is used for mode shapes cross orthogonality inspection and improvement. The computed or measured normal mode sets are the basis for flutter analysis by means of several tools and methods, like MSC.Nastran and ZONA commercial software as well as our own low-cost software named JG2 for the flutter analysis of low speed aeroplanes and for a preliminary analyses of other aircraft. The differences between the methods lie in determining normal mode set, unsteady aerodynamic model, flutter equation formulation, time of analysis, costs, etc. Examples with results comparison obtained by means of distinguished methods are presented. Some works in the field of aeroelastic analysis with nonlinear unsteady aerodynamic in the time domain using Tau-code and ANSYS Fluent software were also performed. Aeroelastic properties of deformed structures, like a sailplane with deflected wings, can be also analysed. The simplest way of this analysis is the semi-linear approach in which the deflections modify the aircraft geometry for normal modes determination.

2

Identification of main helicopters resonances by ground vibration test

Wiśniowski W.

Journal of KONES

|

2015

|

Vol. 22, No. 2

287--291

EN

Six resonances of the helicopter body standing on the airport apron and at least two resonances of the free helicopters the frequencies of which are within the range of basic loadings by the helicopter rotor is called (8+) model. It was proposed to identify (8+) model with the use of resonance tests. It was indicated that (8+) model allows for detuning the resonances from the frequency of working loads, tracing the process of moving through resonances as well as taking off and landing. The paper presents: example of a helicopter on a test rig and visible vibrations inductors; induction of resonance vibrations, induction of resonance vibrations with the forms of pitching, yawing, rolling; induction of resonance vibrations with the forms of pitching with opposite pylon yawing and tipping with opposite pylon yawing; model of helicopter resonances; the multiplication of the resonance amplitude for various velocities of moving through with visible growth of the resonance frequency and reduction of vibrations amplitude; change of the frequencies at the taking off and landing.

3

Innovationality is the transfer process from the idea to commercialization

Wiśniewski W.

Journal of KONES

|

2010

|

Vol. 17, No. 1

485-488

EN

In today's world, innovationality is synonymous with modernity, development, good governance and strategic thinking. The country 's economy and whole of society should be innovative. The research and development process and the results of the work would be reviewed from the commercialization perspective. The all innovative projects should finish on thefree market, but majority of them end their lives at the research and development stage. The idea of spin-off corporations has to serve the subordination of the entire innovative project realization cycle to the vision of its commercialization. Innovative society and economy require implementation of both large and small innovations, created in large, medium and small R & D programs. In economically leading countries, the mega-programs play an important role in innovationality. small innovation programs are usually created by small research teams and individual inventors. For the balanced development of the country's economy, there is a needfor the variety, both small and large innovation programs. In the absence of an effective opportunity to realize one's own Polish mega-programs, it is worth to consider the mega-program named: ,,Provision of services on the International research market" as a Polish specialty. For 10 years the Warsaw's Institute of Aviation pursues this strategy. The Institute of Aviation employs about 800 specialists, which perform the advanced research of the new materials and designs for the new gas turbine engines and combustion systems.

4

Effect of changes in some design parameters on the dynamic properties of aircraft

Wiśniewski W.

Journal of KONES

|

2010

|

Vol. 17, No. 1

479-483

EN

The aim of the study presented in the paper was to examine the impact of changes related to aircraft modernization, the dynamic properties of an aircraft on the basis of five cases studied experimentally. Which changes in the dynamics of an aircraft structure occurred as a result of modernization can be experimentally tested by resonance tests. For this purpose, resonance tests should be carried out before the aircraft modernization and after its completion. In order to mapping the conditions of free flight the objects were suspended flexibly. The electrodynamics actuators were used to induce vibrations, piezoelectric transducers were used for the measurement of vibrations. The size and phase of extortion forces and their application points were selected individually for each resonance in order to get the best separation of it. The first stage of the study was based on recordings the frequency - amplitude characteristics. The second stage of the study was the Identification of individual frequencies and mode shapes of each resonance, which was implemented by choosing the size and the proportion of mutual phase shifts between the extortion forces. In the selection the criteria based on minimizing the phase difference of vibrations measured at several points of the structure were used. The final stage of this study was to register the frequency and shapes mode of the tested resonance and the resonance generalized masses and damping coefficients.

5

Application of transfer path analysis to airplane diagnostics.

Mendrok K., Lisowski W., Uhl T.

Zagadnienia Eksploatacji Maszyn

|

2003

|

Vol. 38, nr 3

83-93

EN

In this paper the operational modal analysis of the PZL M28 Skytruck airplane is presented as well as the transfer path analysis. The operational test was performed for several flight conditions and their results are compared. Comparison is focused on the natural frequency and damping ratio variation with flight conditions change. Additionally transfer path analysis of the airplane was performed.

PL

W artykule zaprezentowano eksploatacyjną analizę modalną samolotu PZL M28 Skytruck oraz analizę rozchodzenia się energii. Test eksploatacyjny został przeprowadzony dla kilku warunków lotu. Dla każdego stanu lotu przeprowadzono analizę, a ich wyniki porównano. Jako kryterium porównawcze przyjęto zmianę częstości drgań własnych i współczynników tłumienia wraz ze zmianą warunków lotu. Przeprowadzono też analizę rozchodzenia się energii w konstrukcjach i rozważano możliwość jej wykorzystania w diagnostyce lotniczej.