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1
Content available Application of Digital Radiography (Dr) in an Approach to Evaluate the Technical Condition of MiG-29’s Vertical Stabilizers
Luziński Rafał, Synaszko Piotr, Dragan Krzysztof
Fatigue of Aircraft Structures
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2021
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Iss. 13
1--7
EN
The purpose of the work presented was to evaluate the capabilities of digital radiography to detect cracks in the internal structure of MiG-29 vertical stabilizers. The test object was a stabilizer previously subjected to fatigue testing and partially torn down for the needs of visual inspection. An inspection of three regions containing cracked parts was performed, with use of a pulsed x-ray generator and digital detector array. The results confirmed the method could be used to detect cracks in an internal structure which could not be inspected with other methods without affecting the stabilizer’s integrity.
2
Content available Analysis of the Corrosion Resistance of Aircraft Structure Joints with Double-Sided Rivets and Single-Sided Rivets
Kamińska Paulina, Synaszko Piotr, Ciężak Patryk, Dragan Krzysztof
Fatigue of Aircraft Structures
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2020
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Iss. 12
57--68
EN
An important factor having a negative impact on the technical condition of aircraft structure elements is the adverse effect of the atmosphere, which causes formation of corrosion in aircraft structures, especially in riveted lap joints. The electric potential difference between the sheet material and the rivet, in the presence of humid air, may cause electrochemical corrosion. The paper presents specimens that imitate the repair on the Mi-24 helicopter with the use of blind rivets in places where solid double-sided rivets could not be used.The aim of the research was to assess the corrosion resistance of lap joints with the use of single-sided and double-sided rivets. The analysis of corrosion resistance was carried out based on accelerated aging tests in a salt spray chamber. The salt chamber tests were aimed at determining the changes taking place in the specimens exposed to the marine environment. In the course of periodic observations changes in the mass of the specimens and in the form of corrosion losses were recorded. These activities were aimed at determining whether the exposure of specimens in the salt chamber causes electrochemical corrosion or pillowing. In addition, the specimens were subjected to static strength tests to assess the effect of corrosion on the strength properties of riveted joints.
3
Content available 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.
4
Content available Comparison of Pulse Thermography (PT) and Step Heating (SH) Thermography in Non-Destructive Testing of Unidirectional GFRP Composites
Kamińska Paulina, Ziemkiewicz Jarosław, Synaszko Piotr, Dragan Krzysztof
Fatigue of Aircraft Structures
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2019
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Iss. 11
87--102
EN
This paper presents two techniques of active thermography i.e. the pulsed thermography technique and the step heating technique. The aim of this article is to compare these two techniques and present the possibilities, advantages and limitations of their use in the context of non-destructive testing of composite materials. The experimental section presents the results of tests carried out on samples of the polymer composites reinforced with glass fiber.
5
Content available 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.
6
Content available A Comparison of Composite Specimens Damage area Measurements Performed using Pulsed Thermography and Ultrasonic NDT Methods
Luziński Rafał, Ziemkiewicz Jarosław, Synaszko Piotr, Żyluk Andrzej, Dragan Krzysztof
Fatigue of Aircraft Structures
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2019
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Iss. 11
68--77
EN
Carbon fiber reinforced plastics (CFRPs) are widely used in aerospace structures due to their high stiffness, strength and good fatigue properties. They are however vulnerable to loads perpendicular to their plane and, while impacted, can suffer significant internal damage decreasing their overall strength. Detecting and sizing such damage is an important task of the non-destructive inspection (NDI) methods. This study was conducted to detect and quantify damage in a set of six impacted even rectangular CFRP specimens designed from a MiG-29 vertical stabilizer’s skin. The inspection was done using the ultrasonic (UT) method (based on mobile scanner – MAUS V) and the pulsed infrared thermographic (IRT) method. Each specimen’s inside and outside (impacted) surface was inspected separately with IRT, while the outside surface was then inspected with UT. UT provided the most precise measurements of the damage area, while the IRT inspection of the outside surface (which would be accessible on a real aircraft structure) provided underestimated values due to the damage’s depth and geometry.
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