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]

X-ray computed tomography is more often applied in non-destructive testing the quality of construction elements significantly crucial for reliability and safety of device elements, machines and complex industrial systems. This article describes the computed tomography (CT) system used to inspect the technical condition of turbine blades of the aircraft engine. The impact of the experimental conditions on the correctness of the obtained results was determined. The appropriate selection of parameters for the experiment was given, and the correct test results of gas turbine blades were presented. Failures, manufacturing defects, material deviations of nickel-cobalt alloyed blades were identified. The thickness of walls was measured in the selected cross-sections with the accuracy of 0.01 mm, and selected manufacturing defects of cooling passages were diagnosed. It was demonstrated that the application of the CT system allows for detailed non-destructive inspection of the technical condition of machine parts. The test results proved that the X-ray computed tomography could be applied in the production and repairs of machines.

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.

No abstract

The reliability and operational safety of an aircraft engine gas turbine are extremely important in terms of its operation. In the course of operation, these turbines undergo complex thermal, mechanical, aerodynamic, and chemical exhaust gas loads. Due to such a load, particularly acting upon the rotor blades, they undergo various damages. Therefore, the maintenance processes continuously strive for enhancing diagnostic methods in order to improve the sensitivity and reliability of damage identification. The basic diagnostic method is a visual one, supported by an optoelectronic device. It only enables determining the fact of a damage, e.g., mechanical, thermal, or chemical. The turbine blade material degradation degree is very difficult to assess in a nondestructive manner in the course of engine operation. No objective, and yet nondestructive, diagnostic method enabling the assessment of blade alloy structural changes has been developed so far. Therefore, a thesis was put forward that it was possible to apply the visual method and correlate its results with the results of gas turbine blade microstructural change tests, which would enable detecting early damage phases and assessing their fitnesses. The tests were conducted with the laboratory method. The authors received new blades of the SO-3 aircraft gas turbine engine made of the EI-867 WD alloy and then subjected them to heating in a laboratory furnace, over a temperature range of T = 1123–1523 K, in increments of 100 K. Cooling took place in the furnace. Prior to and after heating, the blades were subjected to visual testing. Blade surface colour is a diagnostic symptom which indicates a change in the blades’ technical condition. The images were analysed using software developed for the MATLAB environment. The extracted surface image features are presented in the form of brightness distribution histograms for individual colour components RGB(red, green, and blue) and grayscale Sz. Histogram parameters — average value, standard deviation, maximum value and its position — were calculated. In consequence of conducted studies, it was concluded that an increase in blade heating temperature entailed changes in individual RGB colours and the grayscale (Sz) of their surface images, which indicate the overheating intensity.