Article citation info: (*) Tekst artykułu w polskiej wersji językowej dostępny w elektronicznym wydaniu kwartalnika na stronie www.ein.org.pl Grądzki r, LindsTedT P. Method of assessment of technical object aptitude in environment of exploitation and service conditions. eksploatacja i niezawodnosc -Maintenance and reliability 2015; 17 (1): 54-63. rafał Grądzki Paweł LindsTedTMethod of assessMent of technical object aptitude in environMent of exploitation and service conditions Metoda oceny stanu zdatności obiektu technicznego w otoczeniu warunków użytkowania i jakości obsługi* In the article, results of exploitation research of three various technical objects (public transportation bus engines) are presented. Gathered data is presented in three sets (1 -concerning object, 2 -concerning driving conditions, 3 -concerning driver, where sets 2 and 3 are object environment) in form of points (expert number assessments). Relation between point information on object and point information on environment was described using coupled state interaction equations. Such approach allowed to determine the following for each moment of exploitation: technical condition parameter a T and operating condition parameter a R , therefore in each moment of exploitation data regarding operating and technical condition of exploited object (bus) is available.This data allows for identification of object aptitude condition and thus optimally control processes of exploitation and service of particular objects as element of set of objects and set of objects. Keywords: diagnostics, regulation, aptitude. W artykule przedstawiono wyniki badań eksploatacyjnych trzech różnych obiektów technicznych (silników autobusów komunikacji miejskiej). Zebrana informacja została przedstawiona w 3 zbiorach (1 -dotyczy obiektu, 2 -dotyczy warunków jazdy, 3 -dotyczy kierowcy; przy czym zbiory 2 i 3 stanowią otoczenie obiektu) w postaci umownych punktów (eksperckich liczbowych ocen). Relację między punktową informacją o obiekcie i punktową informacją o otoczeniu opisano za pomocą sprzężonych równań stanu. Takie podejście pozwoliło wyznaczyć dla każdej chwili eksploatacji: parametr stanu technicznego aT i parametr stanu działania aR, Zatem w każdej chwili eksploatacji może być dostępna informacja o stanie technicznym i stanie działania każdego eksploatowanego obiektu (autobusu). Informacja ta pozwala identyfikować w każdej chwili stan zdatności obiektu, a zatem pozwala optymanie sterować procesami użytkowania i obsługi poszczególnych obiektów jako elementu zbioru obiektów i zbiorem obiektów.Słowa kluczowe: diagnostyka, regulacja, zdatność. IntroductionLong term exploitation of machine leads to its gradual damage caused by decrease in its material properties and mechanical wear. Technical service is therefore tasked with constant (current) assessment of object technical condition and ability of proper operation of technical objects based on measured diagnostic signals, exploitation signals and conditions in which the object is exploited. This allows to observe chan...

Rotating machines are exposed to different faults such as shaft cracks, bearing failures, rotor misalignment, stator to rotor rub, etc. Therefore, turbogenerators, aircraft engines, compressors, pumps, and many other rotating machines should be constantly diagnosed to warn about the probable appearance of a possible rotor failure. Unfortunately, despite the ongoing work on various rotor fault detection methods, there are still very few techniques that can be considered as reliable and applicable in practical problems. The difficulty lies in the fact that usually the fault introduces very subtle local changes in the overall structure of the rotor. The symptoms of these changes must be isolated and extracted from a wide spectrum of vibration data obtained from sensors measuring the vibrations of the machine. The measured data are usually disturbed with some noise or other disturbances, and that is why the detection of a possible rotor fault is even more difficult. The paper presents a new rotor fault detection method. The method is based on a new diagnostic model of rotor signals and external disturbances. The model utilizes auto-correlation functions of measured rotor's vibrations. By proper processing of the measured vibration data, the influence of environmental disturbances is completely compensated and reliable indications of the possible rotor fault are obtained. The method has been tested numerically using the finite element model of

In the article, new method of monitoring of rotor machine blades technical condition is presented. This method is based on diagnostic model φT12T01 [ which uses phase shift difference of signal fragments resulting from blade operation y (t) during blade recession from sensor and during approach of blade tip towards the sensor as well as signal of its environment x (t) described using proper distribution. The assumed diagnostic model also indirectly includes actual blade environment x (t) without necessity of its measurement [3,. Contactless inductive sensor constantly measures the signal of operating blade transition below the sensor. However, several difficulties with determination of last sample of blade receding from the sensor with first sample of blade approaching the sensor exist. Additionally the problem occurs with measurement of space between blades. So far, the case was solved by use 90% of this space range (in order to eliminate the overlapping of adjacent blades signals). Hence the problem of assessment of measurement period breadth on obtained models (images) of blades. The possibility of blade damage detection by analysis of less than 90% signal course was tested.

This paper presents the bases of a new method of monitoring technical condition of turbomachine blades during their operation. The method utilizes diagnostic models such as a quotient of amplitude amplification and a phase shift of a diagnostic signal y(t) which is a result of blade operation as well as a signal x(t) of blade environment while a blade tip approaches a sensor, amplitude amplification and phase shift of these signals while the blade tip moves away from the sensor.The adopted diagnostic models indirectly take into account the existing environment of a blade, represented by the signal x(t), without the need to measure it [13,15]. Thus, the model is sensitive to the changes in technical condition of blades and practically insensitive to a change in environment. The suggested method may prove very important in diagnostics of rotor blades during turbomachines operation (compressors, turbines etc.).

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.