Paweł Lindstedt

Rotor Blades Condition Monitoring Method Based on the Elimination of the Environment Signal

Rotor Blades Condition Monitoring Method Based on the Elimination of the Environment Signal The paper presents fundamentals of a new method for monitoring of technical condition demonstrated by blades of rotor machines during operation thereof. The method involves the diagnostic model expressed as a quotient of the amplitude amplification for the diagnostic signal y(t) that results from the blade impact and the signal x(t) produced by the blade surrounding when the blade tip approaches the sensor, divided by the amplitude amplification of these signals when the blade tip has already passed the sensor position and moves away. The adopted diagnostic model takes account for current surrounding of the blade x(t) with no need of measurements of its parameters [12, 14, 15]. Thus, the model is sensitive to alterations of the technical condition demonstrated by the blade but very little vulnerable to variations in the blade surroundings. Consequently, the proposed method may be able to play an important role for diagnostics of rotor blades during operation thereof.

Prediction the Bearing Reliability on Basis Diagnostic Information

Prediction the Bearing Reliability on Basis Diagnostic Information The new complex method of diagnostics of helicopters turbine engine Allison 250 in work was. This method be bases on complex diagnostic signals of resulting with simultaneous use three autonomic methods of diagnosing (functional diagnosing, wibroacustic diagnosing and tribologic diagnosing) and of surroundings described with number of crossings of diagnostic sill timbers of these signals. This way of description permits to establish between diagnostic signals quantitative reports and the surroundings and the state of technical object. It the diagnostics was conducted of arrangement bearings two engines Allison 250 built-up on helicopter PZL - KANIA. It was showed, that captured in this way diagnostic signals can be used to prediction of reliability profiles of arrangement bearings. Predykcja Charakterystyk Niezawodnościowych Układu Łożyskowa W pracy przedstawiono nową kompleksową metodę diagnostyki turbinowego silnika śmigłowcowego Allison 250. Metoda ta bazuje na kompleksowych sygnałach diagnostycznych wynikających z jednoczesnego zastosowania sygnałów trzech autonomicznych metod diagnozowania (funkcjonalnej, wibroakustycznej i tribologicznej) i sygnałów otoczenia opisanych liczbą przekroczeń progów diagnostycznych tych sygnałów. Ten sposób opisu pozwala ustalić ilościowe relacje między sygnałami diagnostycznymi i otoczenia i stanu technicznego obiektu. Przeprowadzono diagnostykę układu łożyskowania dwóch silników Allison 250 zabudowanych na śmigłowcu PZL - KANIA. Wykazano, że ujęte w ten sposób sygnały diagnostyczne mogą być wykorzystane do predykcji charakterystyk niezawodnościowych układu łożyskowania.

Newtonian and Bergsonian time in technical diagnostics

Testing and reasoning are two main closely related diagnostic activities. Diagnostic testing is realized in Newtonian (short) time while diagnostic reasoning in (long) Bergsonian time. Both sort of time are used to analyze different kinds of problems in diagnostics and reliability of technical objects. Newtonian and Bersonian time differentiation needs some expert knowledge. In this paper, considerations are based on observation that Newtonian time of diagnostic testing is related to object maintenance (adjustment) and Bergsonian time is related to object is reliability. A significant change of the object’s technical condition (signals or parameters of the state) causes changes of its regulation state (quality indicators change) and the characteristics of reliability. As it is required for the operation and reliability to be always appropriate and permanent, the control should be adjusted to functional needs of the object, and the use should be adapted to the current characteristics of reliability. Therefore, change of the settings of the control device (made during the handling of the object) represents the change of technical condition and state of reliability. It is presumed that, during the operation of a technical object, the selection of the control settings for damaged object is impossible. This fact, when predicted, becomes the basis for the prediction of the object reliability.

A method of parametric evaluation of the technical object reliability

A Method of Parametric Evaluation of The Technical Object Reliability This work presents a practical and effective method to evaluate the reliability status of an object basing on the observation of changes in its functioning (automatics) and its technical condition (diagnostics). It has been observed that changes of the functioning condition potential could serve to determine the symptoms of transient (momentary) damages and the changes in the potential of the technical condition to determine the symptoms of parametric damages (non-total). Such an information, as it turns out, is sufficient to calculate reliability characteristics before dangerous catastrophic damages occur and to calculate reliability characteristics for every single object without having to deal with a numerous set of objects. The presented computer-aided method can be of a substantial practical importance in coordination of adjusting/control functions, diagnostics and reliability actions and thanks to that it can improve the level of organisation of a system operation. Metoda parametrycznej oceny stanu Niezawodności obiektów technicznych W artykule przedstawiono praktyczną i skuteczną metodę oceny stanu niezawodności obiektu, bazującą na obserwacji zmian jego stanu działania (automatyka) i stanu technicznego (diagnostyka). Dostrzeżono, że zmiany potencjału stanu działania mogą być podstawą do wyznaczania symptomów uszkodzeń przemijających (chwilowych), a zmiany potencjału stanu technicznego do wyznaczania symptomów uszkodzeń parametrycznych (niecałkowitych). Tak uzyskana informacja jest wystarczająca do obliczania charakterystyk niezawodnościowych w czasie przed pojawieniem się niebezpiecznych uszkodzeń katastroficznych oraz obliczania charakterystyki niezawodności dla każdego pojedynczego obiektu bez konieczności dysponowania licznym zbiorem obiektów.

The Method of Assessment of Suitability of the Bearing System Based on Parameters of Technical and Adjustment State

In the operation process, a complex method evaluating technical condition and regulatory status (activities) of the bearing system is used. The method of determination of technical parameters and operating status is known. This is achieved through the interaction of two coupled equations and [2, 3, 7]. It was demonstrated that, on the basis of waveform parameters of technical condition and operating status (respectively), the identification of parametric and momentary damage can be carried out. During the identification process of parametric and momentary damage, it is assumed that damage arises when a parameter threshold value at the time of operation is greater than current permissible value. It is shown how the threshold value of the parameter and its current permissible value, taking into account the number of measurements, are determined.

PREDICTION OF ESTIMATES OF TECHNICAL OBJECT'S RELIABILITY ON THE BASIS OF DAMAGE DETERMINED FROM LINDBERG LEVY'S CLAIM AND MULTIPLICITY OF THE SET SPECIFIED FROM ERGODICITY STREAM DAMAGE

During the exploitation one problem still unsolved is that of determining reliability characteristics for single (individual or small set) technical object. This particularly concerns identification of damage set (parametrical and momentary) as well as determination of substitute cardinality of objects set, where in fact this equals 1, 2, 3 at the most. The article presents a method of determining parametrical and momentary damages from iteration equations:

Examination of Operational Dependability Demonstrated by Turbine Reactive Engines

Examination of Operational Dependability Demonstrated by Turbine Reactive Engines The paper presents course and results of operational examination carried out for engines with particular consideration of land-based tests. It has been suggested that available, already recorded signals from the automatic and control systems can serve as a basis for assessment of the engine operability. The recorded signals can be analyzed in various manners, including the method that is based on the phase trajectory superposed with the Lyapunov function. It has been shown that analysis of signal interrelations presents substantial advantages, where the movement of the phase trajectory vector over the time period is subject to analysis and is related to successive values of the Lyapunov function that is calculated for subsequent moments of time (possibility to analyze both linear and non-linear systems, simultaneous analysis of three signals: operational, environment and feed), therefore the proposed method prevails over other approaches to analysis of signals. The final part of the paper deals with analysis of signals obtained from recorded waveforms from the automation and control systems of the K-15 engine. Eksploatacyjne Badania Stanu Zdatności Turbinowego Silnika Odrzutowego W pracy przedstawiono badania eksploatacyjne silnika ze szczególnym uwzględnieniem prób naziemnych. Zasugerowano, że podstawą oceny zdatności silnika są dostępne, zarejestrowane sygnały automatyki (regulacji). Przedstawiono różne metody analizy zarejestrowanych sygnałów, w tym metodę opartą na trajektorii fazowej z naniesioną funkcją Lapunowa. Wykazano przewagę analizy relacji między sygnałami, której podstawą jest badanie ruchu wektora trajektorii fazowej w czasie, względem kolejnych w czasie różnych wartości funkcji Lapunowa (możliwość badania układów liniowych i nieliniowych, jednoczesna analiza trzech sygnałów: użytkowego, otoczenia i zasilania) nad innymi metodami analizy sygnałów. Podano przykłady analizy sygnałów na podstawie zarejestrowanych przebiegów sygnałów automatyki (regulacji) silnika K-15.

Rotor Blades Diagnosis Method Based on Differences in Phase Shifts

In this work, an innovative diagnosis method of rotor blades is presented. A measurement signal of blade tip displacement is divided into two observation zones, in which two peaks of an additional template signal are introduced. Cross-correlation and power spectral density functions of the measurement and template signals in these two distinct zones are calculated. Next, the phase shift between the two cross-correlation functions is obtained by calculating the ratio of the two power spectral density functions. The changes in parameters of an analytical description of this phase shift are used to determine a distinct and easy-to-analyze image of the technical condition of the tested blade. A graphical portrait indicating the technical condition of all blades in the annulus is developed. Although not directly measured, environmental signals (e.g., external disturbances and sensor’s noise) affecting the diagnostic process are included in the method. It is demonstrated that, by using the proposed signal processing technique, a negative influence of these disturbances is eliminated and the reliability of the machine technical condition indications is improved. The approach is demonstrated using experimental results of turbine engine blade displacements. High effectiveness of the method and measurement equipment has been confirmed in a wide range of analyzed tip-timing results obtained in different periods of the measurement process.

Identification of Parametric and Momentary Damages on the Basis of Lindeberg-Levy’s Model

Article presents the innovative method for the assessment of reliability condition of the exploited system, based on the appropriate analysis of changes in the current parameters of technical condition aRb and the regulation condition aRc, determined from the compressed condition equation (1 and 2). While analyzing the course of momentary parameters for technical condition aRb and the regulation condition aRc, it was observed that the parametric and momentary damages can be identified on the basis of quantitative relations between momentary threshold value dpr and corresponding momentary permissible value dprdop, which are calculated from equation (7, 8, 9) resulting from Lindeberg-Levy’s theorem. It is assumed that the damages are prevailing, when for the moment θi: dpri>dpr dopi. With the number of damages (damage map), reliability parameters for each moment of exploitation of technical object (before the catastrophic damages will occur) can be determined. Parametric damages (expected lifetime E(T) and standard deviation of expected lifetime σE(T) provides the reasonable information for the appropriate planning of the servicing of exploitative objects.

The Concept of Monitoring Blades of Rotor Machines with the Identification of their Vibration Frequency

Abstract The paper presents the basis of a new method for monitoring the technical condition of rotating blades during their operation. Utilizing the measurement of blade tip instantaneous speed under subsequent sensors, enables direct determination of the blade vibration frequency. The method utilizes a diagnostic model in the form of amplitude amplification W2ij and phase shift φij of a diagnostic signal y(t) resulting from the operation of the blade and the signal from its environment, when the blade tip passes under a cascade of blade tip instantaneous speed sensors. The adopted diagnostic model, indirectly takes into account the current surrounding of a blade without the need to measure it [12, 14]. Evaluation of the blade technical condition in real time and static analysis shall be performed on the basis of the vibration process parameter analysis. The suggested method may play an important role in the diagnostics of rotor machine blades during their operation.