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1

Geogrid as an effective reinforcement of natural airfield pavements

Kowalewska Agata, Wesołowski Mariusz, Kłysz Sylwester

Journal of KONBiN

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2023

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Vol. 53, iss. 2

1--15

EN

The load-bearing capacity of natural airfield pavements is crucial for air operations safety. Taking into account the insufficient load-bearing capacity of natural airfield pavements, which is confirmed by the conducted tests in this field, the article presents a tangible impact of the application of geocells (geogrids) as an efficient way of their reinforcement with particular emphasis on the improvement of their load-bearing capacity. The recovery time of airfield operational capability compared to the currently applied reinforcement methods of natural pavements, such as mechanical or chemical surface stabilization or surface replacement, was showcased.

PL

Parametr nośności naturalnych nawierzchni lotniskowych ma istotne znaczenie w aspekcie bezpieczeństwa wykonywania operacji lotniczych. Mając na uwadze niedostateczną nośność naturalnych nawierzchni lotniskowych, co potwierdzają dotychczas przeprowadzone badania w tym zakresie, w artykule przedstawiono wymierny wpływ zastosowania geosyntetyków komórkowych (geokrat) jako skuteczny sposób ich wzmocnienia ze szczególnym uwzględnieniem poprawy ich nośności. Zwrócono także uwagę na zaletę geokrat, jaką jest czas przywrócenia zdolności operacyjnej lotniska, w porównaniu do aktualnie stosowanych sposobów wzmacniania nawierzchni naturalnych, jak np. stabilizacja mechaniczna i chemiczna gruntu czy wymiana gruntu.

2

Safety-overrunning clutch elastic torque operation characteristic study

Protsenko Vladyslav, Malashchenko Volodymyr, Kłysz Sylwester, Avramenko Oleksiy

Diagnostyka

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2023

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Vol. 24, No. 4

art. no. 2023415

EN

The article deals with ball-type safety-overrunning clutches' elastic characteristics in overload mode. Main semi-couplings geometric parameters, particularly ball stroke and semi-couplings twisted angles, affecting operation speed and clutch elastic torque considered and obtained expressions for this parameters determination. Main clutch parts force interaction features in the final overload operation period analyzed and ratios for the clutch final period load are obtained. Based on current and previous studies, the expressions for elastic torque in the overload operation period are estimated. Obtained results could become the tool for the dynamics analysis of studied clutch-equipped driving operation during the clutch reengagement in overload mode. It is shown the expedience of using in high-speed driving clutches with large values of grooves to clutch axis inclination angle to decrease dynamic loads in driving, because in little and middle angles values provide nosedive dropping of final stage torque which can become a source of intense oscillations in the driving equipped with clutch in overload mode.

3

Load capacity and design parameters of ball-type safetyoverrunning clutch with inclined grooves sides

Protsenko Vladyslav, Malashchenko Volodymyr, Kłysz Sylwester, Nastasenko Valentyn, Babiy Mykhaylo, Avramenko Oleksiy

Diagnostyka

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2022

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Vol. 23, No. 4

art. no. 2022403

EN

Article deals with safety-overrunning clutches for mechanical transmissions. Modern design of safetyoverrunning clutch with grooves sides inclined to semi-coupling radius has been described and researched in the article. It has practical value for creation modular-type machines. On the basis of the theoretic studies, the expressions for obtaining the main specific operation parameters have been proposed: rating torque, beginning and ending operation torques. As the result of the studies, the equations for estimation the clutch main operation characteristics have been received - rating torque exceeding coefficient, coefficients of clutch accuracy and sensitivity. On account of modeling and comparison with clutch where grooves sides are parallel to the radius made a number of important conclusions. The analysis performed demonstrates that clutches with inclined to radius grooves sides in general have higher operation characteristics compared with clutches with parallel to radius grooves sides, particularly higher accuracy coefficient and lower rating torque exceeding coefficient. Obtained results make it possible to recommend for highly loaded large-mass systems clutches with low values of grooves to clutch axe and grooves sides to radius inclination angles, because it provides balls contact with plane sides grooves surfaces and through this allows to decrease contact stresses compared with clutches with grooves sides parallel to radius; allows to provide high load capacity with low rating torque exceeding in overload mode; in clutches with inclined to radius grooves sides friction impact manifests less in operation with high rotation frequency.

4

Force parameters and operating characteristics of safety-overrunning balltype clutch

Malashchenko Volodymyr, Protsenko Vladyslav, Kłysz Sylwester, Nastasenko Valentyn, Babiy Mykhaylo

Diagnostyka

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2021

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Vol. 22, No. 3

43--50

EN

Article deals with the field of machinery, namely with the protecting of devices for mechanical driving systems. New construction of safety-overrunning clutch, operating on gearing principle, where safety and overrunning parts are mutually integrated, has been proposed and studied in the article. It has practical importance for building, based on modular principles, machines. As the result of the theoretic studies, the expressions to calculate the following specific clutch torques have been obtained: rating torque, torques of beginning and ending of operation. On the basis of the mentioned studies, the expressions to estimate the clutch main operation characteristics have been obtained - nominal torque exceeding coefficient, accuracy and sensitivity coefficients. These expressions are practically important for proposed clutch calculations. The analysis performed demonstrates that in order to increase the clutch load capacity, the grooves must be made with less inclination angles to clutch axis. Obtained results indicate the advisability of installing the clutch on low-speed shafts. It is shown that the clutch overload sensitivity could be increased by the reduction of the spring rigidity. The calculations performed also demonstrate that balls diameter reduction has a positive effect on the clutch operation parameters. Obtained expressions and numerical results are practically important for proposed clutch calculations. It is shown that in terms of the accuracy of operation, the studied coupling fully corresponds to the level of common and investigated designs of safety clutches.

5

Investigation of low- and high-cycle fatigue in Al 2024-T4 alloy

Kłysz Sylwester

Technical Sciences / University of Warmia and Mazury in Olsztyn

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2020

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nr 23(4)

309--321

EN

The article presents the results of low- (LCF) and high-cycle fatigue (HCF) analyses of 2024-T4 aluminum alloy which is used in aircraft construction, mainly for highly loaded structural components, including for plating, fuselage frames and rotor blade girders in helicopters. The alloy is used in structures where a high strength-to-weight ratio and high fatigue resistance are required. However, the alloy is poorly weldable and has low corrosion resistance. The tests were performed on hourglass and cylindrical samples with parallel and perpendicular orientation relative to the rolling direction. Samples for analysis were obtained from the production line of PZL-130 Orlik TC-II trainer aircraft. The results of the analysis were described by Manson- -Coffin and Morrow equations.

6

Mechanical Tests Applied to Structural Health Monitoring: An Overview of Previous Experience

Baran Marta, Nowakowski Dominik, Lisiecki Janusz, Kłysz Sylwester

Fatigue of Aircraft Structures

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2020

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Iss. 12

123--135

EN

Laboratory for Materials Strength Testing (LMST) has been conducting accredited mechanical research for aviation from 2003. Among accredited procedures are e.g. low and high cycle fatigue tests, fracture toughness tests and fatigue crack growth rate tests. The main goal of them is obtaining materials constants and characteristics. However knowledge how to conduct these tests could be used also in other applications, for instance in the work on development of Structural Health Monitoring systems (SHM). When cracks propagate in a controlled way in laboratory conditions, it allows verifying the operation of a single sensor or a network of sensors. In this paper, an overview of mechanical tests carried out at the Laboratory for Materials Strength Testing within Air Force Institute of Technology (AFIT) work on research and development of SHM systems is presented. Specimens prepared from materials such as aluminum alloys (among other withdrawn PZL-130 Orlik TC-II aircraft) and CFRP composite were tested under different mechanical loads, i.e., cycle and impact loads. In the presented research, both constant amplitude and spectrum loads were applied.

7

Examination of Honeycomb Core Compliance in Sandwich Structure

Nowakowski Dominik, Baran Marta, Lisiecki Janusz, Kłysz Sylwester, Synaszko Piotr

Fatigue of Aircraft Structures

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2019

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Iss. 11

19--27

EN

The objective of the research presented in this paper was to determine the honeycomb core compliance of a sandwich structure of the horizontal stabilizer of the MiG-29 fighter jet in the static compression test. The study of the specimen was conducted based on the ASTM C365/C365M standard. The article presents the results of experimentally determined dependencies and strength parameters, i.e. the force-displacement dependence, the compressive modulus and the honeycomb core deformations.

8

Comparative Study on Fatigue Life of CFRP Composites with Damages

Baran Marta, Synaszko Piotr, Lisiecki Janusz, Kłysz Sylwester

Fatigue of Aircraft Structures

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2019

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Iss. 11

28--38

EN

In this work, the compressive residual strength tests results, Compression After Impact (CAI), are presented. The specimens were made of carbon-epoxy prepreg E722-02 UHS 130-14. Two variants of specimens were tested: samples undamaged and samples with damage that was centrally introduced by a drop-weight impact, as per the ASTM D7136/7136M standard. An impactor with potential energy equal to 15J and the type of support required by the standard were used. The size of impacted damages, defined as an area of damage on a plane perpendicular to the impact direction, and the equivalent diameter were specified using the flash thermography method. The tests were performed using the fixtures manufactured according to the ASTM D7137/7137M standard. The specimens were compressed to determine the residual strength. This value was afterwards used to specify the force levels for the fatigue tests. The fatigue tests were carried out under force control – with a sinusoidal shape, stress ratio R equal to 0.1 and frequency f 1Hz. Maximum force in a loading cycle Pmax was being increased after each thousand of cycles N until its value was close to the residual strength determined in the previously mentioned tests. In this work, the following relationships were presented: force-displacement P-δ for both static and fatigue tests and displacement-loading cycles δ-N for fatigue tests. A method of conducting the fatigue tests of CFRP composite was proposed, in which both the CAI specimens and CAI fixture were used. This allowed researchers to accelerate making initial comparisons between the two groups of specimens with damages – grouped relative to the way of conditioning.

9

Investigation of the energy effectiveness of multistage differential gears when the speed is changed by the carrier

Malashchenko Volodymyr, Strilets Oleh, Strilets Volodymyr, Kłysz Sylwester

Diagnostyka

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2019

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Vol. 20, No. 4

57--64

EN

The energy effectiveness of the multistage gear differential in the device for speed change by carrier has been investigated with the determination of the efficiency. Considering complexity of the problem, the analytical methods of efficiency determining for two- and three-stage differential gears have been obtained and proposed using the potential power method, when the driving link is the first-stage sun gear, the driven link is the ring gear of the last stage or vice versa, and the links of the speed change control are the carriers of the individual stages. With the help of computer modeling of analytical expressions, graphical dependences of efficiency from the ratio of the multistage differential gear and the angular velocity of the control link - the carrier, have been obtained. The results obtained have practical application for the design of new devices by means of energy effectiveness, allow to evaluate the operation of multistage differential gears from the point of view of self-breaking and are of assistance for further research.