Reconstructing the Load-Bearing Capacity of Deteriorated, Concrete Airfield Pavements Using Prefabricated Slabs

The age of currently operated concrete airfield pavements in Poland exceeds 30 years operation period many times. Such a long working life of airfield pavements forced to search for the efficient and fast technologies of their reconstruction. The article described in detail the technologies of fast reconstruction of airfield concrete slabs using prefabricated slabs. The addressed technology guarantees the reconstruction and even the improvement of the condition of loadbearing capacity of mentioned airfield slabs which was confirmed during laboratory tests, field tests and practically verified in the real operation in the International Airport Kraków-Balice.

Application Concept of the Active Magnetic Suspension Technology in the Aircraft Engine

The paper presents the results of work on control and monitoring systems of an active magnetic bearings for the aircraft engine. Mathematic model of the active homopolar electromechanical actuator with permanent magnets is expanded. Mathematical model of the test object is developed what allows to propose a control algorithm. The experimental verification of this theory was performed on the laboratory test stand. Moreover, special monitoring system is also designed. Presented comprehensive approach allows increasing reliability of the aircraft engines, as well as in wind turbines, electric drives and machine tools spindles.

The Impact of Technology on Poisson’s Ratio of Auxetic Polyurethane Foams

The article presents a method for measuring Poisson’s ratio of the polyurethane foam, including shapes of the auxetic foam. The impact of technology applied in Air Force Institute of Technology, that is a method for processing the selected polyurethane foams, on the value of Poisson’s ratio of the auxetic foam shape was presented. In order to manufacture the auxetic foam shapes, two methods; mechanical-thermal and mechanical-chemical-thermal, were applied.

Crew – Spacecraft – Environment Anthropotechnical System in View of Engineering Systems

The publication describes an example of the anthropotechnical system (crew-spacecraft-environment) in view of engineering systems, which enables to shape their dependability by simultaneously ensuring the safety of space flight operations and more economical operations. Further research on developing the anthropotechnical system should involve the implementation of the elements of artificial intelligence based on expert systems or artificial neural networks.

The Structure of Classifiers of Hand Gestures with the Use of the Active Contour Model and Fourier Descriptors

In this article, the research results of the usage of selected methods of the analysis of images for the recognition of hand gestures in human-computer interaction was depicted. The usage of this type of interaction is important in case of the so-called wearable computers (computer is integrated with the work clothing of an operator. For the recognition of gestures, the combination of two methods associated with the image processing was suggested and that is the Chan-Vese active contour model enabling to recognize objects on a given image, based on the curve evolution technique, Mumford-Shah functional, level-sets and the methods to create shapes with the use of Fourier descriptors. For the classification criteria as a compatibility measure a scalable Mahalanobis distance was used.

Evaluation of the Load-Bearing Capacity of Natural Airfield Pavements by Military Standard No-17-A503:2017

The article presents the evaluation methodology of the load-bearing capacity of natural airfield pavements in compliance with the Military Standard NO-17-A503:2017. There was addressed the problem frequently occurring on airfields regarding the insufficient load-bearing capacity of natural pavements, which has a direct impact on the safety of air operations by the military and civil aircraft. The approach of the authors of the standard to the complex evaluation of the load-bearing capacity of natural airfield pavements on individual airfield functional elements was described. Moreover, minimum requirements were provided that must be fulfilled to ensure the safety of air operations on natural airfield pavements.

Exemplification of Tomographic Method to Evaluate the Quality of Welded Joints Made from EN 5754-H22 Alloy

The quality of welded joints depends on many factors. The relevant standards stipulate technical conditions of welds quality assessment, which provides the basis for stating whether the given joint is compatible with the requirements or whether it is defective. In practice, making welded joints that are totally devoid of defects is extremely difficult. To conduct the control of inner structure of the given joint a non-destructive method with the application of industrial CT scanner might be applied. This modern diagnosing method combines the x-ray examination with advanced computer technology. The basic advantage of computer-assisted tomography consists in examining objects in three dimensions and the possibility to carry out three-dimensional reconstructions. The aim of this article is to discuss the use of this method to evaluate the quality of welded joints made of aluminium alloys. Capabilities of computer-assisted tomography were depicted by the case of weld probes constructed with TIG (ang. Tungsten Inert Gas) welding by different process variables. One has made the analysis of the quality of probes showing the smallest and the biggest internal and external welding defects.

Value-Focused Thinking Model to Evaluate SHM System Alternatives From Military end User Requirements Point of View

The article describes Value-Focused Thinking (VFT) model developed in order to evaluate various alternatives for implementation of Structural Health Monitoring (SHM) system on a military aircraft. Four SHM system alternatives are considered based on: visual inspection (current approach), piezoelectric (PZT) sensors, Fiber Bragg Grating (FBG) sensors and Comparative Vacuum Monitoring (CVM) sensors. A numerical example is shown to illustrate the model capability. Sensitivity analyses are performed on values such as Cost, Performance, Aircraft Availability and Technology Readiness Level in order to examine influence of these values on overall value of structural state of awareness provided by particular SHM system alternative.

Niezawodność Przykładowego Systemu Technicznego Dla Założonych Funkcji Gęstości Uszkodzeń

Streszczenie Analiza niezawodności strukturalnej systemu technicznego, a zwłaszcza wyznaczenie zmiany niezawodności systemu w czasie, wymaga znajomości funkcji gęstości lub dystrybuant (zawodności) elementów wchodzących w skład struktury. Bazując na zarejestrowanych w przeszłości danych dotyczących uszkodzeń elementów, można w miarę łatwo wyznaczyć średni czas zdatnej pracy elementu oraz odchylenie standardowe dla tego czasu. Natomiast określenie postaci rozkładu nastręcza pewne trudności. Otóż z reguły nie dysponujemy dostateczną liczbą danych do weryfikacji hipotezy o postaci rozkładu. Z tego powodu powszechnie, w zależności od rozpatrywanego przypadku, zakłada się postać funkcji gęstości uszkodzeń. Powstaje pytanie: czy błędne określenie rodzajów rozkładów elementów powoduje duży błąd wyników oszacowania niezawodności i trwałości systemu? Niniejszy artykuł nie odpowie w pełni na to pytanie, ale zostanie dokonane porównanie wyników obliczeń dla kilku przypadków. Obliczenia zostały przeprowadzone dla przykładowego systemu technicznego.

Egzemplifikacja Tomograficznej Metody Do Oceny Jakości Połączeń Spawanych Ze Stopu EN 5754 H22

Streszczenie Jakość połączeń spawanych zależna jest od wielu czynników. Przedmiotowe normy określają warunki techniczne oceny jakościowej spawów, co stanowi podstawę do uznania połączenia za zgodne z wymaganiami lub wadliwe. W praktyce wykonanie połączenia spawanego całkowicie pozbawionego wad jest trudne. Do kontroli wewnętrznej struktury połączenia wykorzystać można nieniszczącą metodę z zastosowaniem przemysłowego tomografu komputerowego. Ta nowoczesna metoda diagnozowania łączy badanie rentgenowskie z zaawansowaną technologią komputerową. Podstawową zaletą tomografii komputerowej jest badanie obiektów w trzech wymiarach oraz możliwość wykonania rekonstrukcji przestrzennych. Celem artykułu jest omówienie wykorzystania tej metody do oceny jakości połączeń spawanych stopów aluminium. Możliwości tomografii komputerowej przedstawiono na przykładzie próbek spawalniczych wykonanych metodą TIG przy różnych parametrach procesu. Dokonano analizy jakości próbek wykazujących najmniejsze i największe zewnętrzne, jak również wewnętrzne wady spawalnicze.