<abstract xmlns="http://www.w3.org/1999/xhtml">

In this work, cast steel G17CrMoV5-10 was investigated. The material subject to investigation as part of this study is commonly used to manufacture steam turbine casings. Modern steam turbines operate under elevated temperature and complex oscillated loads. Thus, the focus of this study was to investigate material under behavior during low cycle fatigue (LCF) test performance at 500°C with and without hold time in tension. During all types of test, cyclic softening of cast steel was noticed. Increasing of total strain rate and applying hold time significantly reduce fatigue life. During hold time, due to temperature and tension the material creep what is confirmed by increasing inelastic stain accommodation.
</abstract>

Effect of Strain Range and Hold Time on High Temperature Fatigue Life of G17CrMoV5-10 Cast Alloy Steel

<abstract xmlns="http://www.w3.org/1999/xhtml">

The study investigates the sensitivity of numerical crack propagation estimations based on the Nasgro equation. The equation is widely used for crack propagation calculations since it considers the whole range of crack propagation speed from threshold to critical values of stress intensity factor range (Δ<italic>K</italic>). The presented investigation is based on the actual results of the full scale fatigue test (FSFT) of the PZL-130 ‘Orlik’ TC-II aircraft. We provide a brief description of the test and the general approach followed in crack propagation estimations originally carried out after the test. The obtained results are verified in terms of variation of the input data. Overall results are compared and discussed.
</abstract>

Sensitivity Analysis of the Nasgro Equation Based on the PZL-130 TC-II Orlik Trainer Aircraft Full Scale Fatigue Test

<abstract xmlns="http://www.w3.org/1999/xhtml">

Fibre metal laminates (FMLs) consisting of layers made of PA6 polyamide prepregs reinforced with glass and carbon fibres and an aluminium alloy core are the new variant of the other types used by aerospace FML materials such as GLARE or CARALL. By using a thermoplastic matrix, they can be shaped by stamping processes, which allows for a more efficient production process than classical laminating methods such as vacuum bagging. In addition to the improved impact energy absorption efficiency, the metallic core can be utilised to effectively bond the composite part to adjacent metallic structures. This article presents the influence of the material configuration of fibre-metal laminates consisting of continuous fibre-reinforced thermoplastic outer layers integrated with a layer of metallic aluminium alloy inserts—a number of layers, type and direction of reinforcing fibres—on the static and fatigue flexural properties. In this study, eight laminate configurations were prepared using a one-step variothermal consolidation process. The results showed that in the three-point flexural fatigue test, the samples exceeded 106 cycles at stresses &lt;30% of the static bending strength. Laminates with predominantly longitudinally reinforced layers showed the highest fatigue strength among the FML samples analysed. The type of reinforcing fibres and the number of layers were less affected on the analysed mechanical properties.
</abstract>

The Influence of Material Configuration of Fibre-Metal Laminates with Alumina Core on Flexural Strength

<abstract xmlns="http://www.w3.org/1999/xhtml">

In the present study it has been endeavored to estimate the fatigue crack propagation in V-notch Charpy specimens of 2024 T351 Al-alloy. For this purpose, a new application of fatigue crack growth (FCG) is developed based on the “Gamma function.” Experimental fatigue tests are conducted for stress ratios from 0.1 to 0.5 under constant amplitude loading. The empiric model depends principally on physical parameters and materials’ properties in non-dimensional form. Deviation percentage, prediction ratio, and band error are used for validation of the performance of the fatigue life. The results determined from Gamma application are in good agreement with experimental FCG rates and those obtained from using Paris law.
</abstract>

Prediction of Fatigue Cracks Using Gamma Function

<abstract xmlns="http://www.w3.org/1999/xhtml">

This work is focused on the checking of the correctness of the brazing process of honeycomb seals to stationary elements of aircraft turbine engines. It describes this process, paying attention to the aspects that have a fundamental impact on whether the seal will be brazed to the base as required, or whether unacceptable areas of non-brazing will appear. The aim of the study was to check the possibility of using the ultrasonic method to check the correctness of the brazing process of honeycomb seals and to compare the tests carried out using this method with the mostly used visual tests. The research carried out as part of the work showed very well that there are reasons to use the ultrasonic defectoscopy method to test the correctness of the brazing process of honeycomb seals in the elements of aircraft engines. This method also makes it possible to automate the checking process, fully document it and objectively assess the correctness of the connection. The results obtained in the study provide a very good starting point for further research, the aim of which will be to implement the ultrasonic defectoscopy method for testing the correctness of brazing honeycomb seals into practice in industrial conditions.
</abstract>

Checking the Correctness of the Process of Brazing of the Honeycomb Seal to the Base by Ultrasonic Method

<abstract xmlns="http://www.w3.org/1999/xhtml">

Blade vibrations in aircraft engines are a significant challenge that must be overcome during the design and development of modern turbine engines. Vibrations lead to cyclic displacements and result in alternating stress and strain in undesired environments (high temperatures, erosion, corrosion of the surface, etc.). Under resonance conditions, stress amplitudes can increase and exceed their safety limits, and in extreme cases, can lead to engine failure. One method to reduce resonance vibrations is to increase damping in the turbine assembly. This paper presents and describes vibration damping sources in the turbine, including aerodynamic, material, and friction damping. Additionally, typical damping values for each damping component are presented and compared.
</abstract>

Insight into Damping Sources in Turbines

<abstract xmlns="http://www.w3.org/1999/xhtml">

The fatigue is an important factor in aircraft operation. A correct estimation of structure fatigue life is crucial for user and payload safety. However, due to high amount of data gathered during a typical recording of load spectra for different types of flights, the overall results become prone to human error. The paper describes development of a software able to perform an automated, in-depth analysis of data recorded with onboard accelerometers. Using the Rainflow Cycle Counting method, it transforms received data points into a Markov matrix. The prepared array is then recalculated into a half-cycle matrix, which can be collapsed into scalar value of fatigue level using the Palmgren-Miner rule. The method was tested with loads recorded during a typical flight conducted according to the Polish NSTS-06 flight scenario and simulated camera mounting fixed to a multirotor.
</abstract>

Automation of Aircraft Fatigue Life Estimation

<abstract xmlns="http://www.w3.org/1999/xhtml">

Brakes are one of the most important safety systems in moving vehicles and machines. In vehicles such as cars or motorcycles brakes are used for stopping, controlling speed, and sometimes changing direction of travel. In aircraft, the main function of brakes is to reduce landing speed. As landing is one of the most dangerous maneuvers in aircraft operation, brakes must be efficient and reliable in order to ensure safety of the crew, passengers, and cargo. The most efficient brakes nowadays are friction brakes where velocity is controlled by friction of a pair of specially designed materials, which ensure stable and high friction coefficient over the course of the required braking process. The process itself is the dissipation of energy during aircraft movement which generates very high temperatures in friction materials during the time of the braking process. The materials and the whole brakes have to be temperature resistant, and we must ensure braking parameters are stable during the whole process. The same principle relates to the endurance/fatigue of the brake assemblies which must be durable enough to survive as high number of braking cycles as possible without any failure, which can result in fatal consequences. Every friction pair and every newly designed brake assembly must be laboratory tested for efficiency and endurance/fatigue in order to be used in an aircraft or vehicle. In this paper, we present the basic set of laboratory tests in the scope of friction materials and brake assemblies. Results of the tests are used as confirmations/proofs of proper and safe operation of the brakes for use in vehicles, especially in aircraft but also in land-based vehicles.
</abstract>

zbigniew.skorupka@ilot.lukasiewicz.gov.pl

Efficiency and Fatigue/Endurance Laboratory Tests of Aviation Friction Brakes

<abstract xmlns="http://www.w3.org/1999/xhtml">

The purpose of this article is to present the results of the investigation regarding the differences of the load spectra of two unmanned fixed-wing aircraft performing photogrammetry missions: X-8 (flying wing) and PW-ZOOM (conventional configuration). The focus was on the analysis of a number of load cycles for various load increments within the range of the operational loads. The load spectra were determined using the acceleration signal recorded in the autopilot logs as an input. This signal was transferred to the chain of local extreme values scaled in the form of discrete load levels, and then the transfer arrays were derived with use of the rainflow counting algorithm. On this basis, the incremental load spectra were determined for each flight. These load spectra were subjected to statistical analyses to determine the load spectra representative of the flight sessions in a few ways between non-conservative (i.e., focused on average load histories) and conservative (i.e., focused on the worst load histories observed during the flight session). Finally, the fatigue life was calculated by having the structural element of the assumed fatigue properties subjected to the load spectra of both airplanes. A large (exceeding one order of magnitude) difference in the number of load cycles for larger load increments in the analyzed load spectra was shown. This difference is related to the different dynamic characteristics of the two aircraft, in particular the gust response. As a result, there is a several-fold difference in fatigue life.
</abstract>

Comparative Analysis of the Load Spectra Recorded During Photogrammetric Missions of Lightweight Uavs in Tailless and Conventional Configurations

<abstract xmlns="http://www.w3.org/1999/xhtml">

This paper presents the results of a structure study of a dispersion composite on a silicone matrix with a filler in the form of multi-walled carbon nanotubes (MWCNTs). The study aims to determine the effect of the filler on the composite mechanical properties and electrical conductivity. Materials that are electrically conductive and exhibit high mechanical properties can find applications in high-strain sensors. During the study, the characteristic properties of the susceptible materials, silicone alone and silicone with different filler contents (4%, 6%, and 8% by weight), were determined after curing. Microscopic observations were performed to assess the influence of carbon fillers on the material structure and to determine the level of homogeneity of the material. Examination of mechanical properties facilitated the determination of the Shor A hardness (ShA), stiffness, and Poisson’s ratio of the cured composites, depending on the nanotubes’ content. In parallel with the study of mechanical properties, the effect of loading, and the associated deformation of the samples, on the conductivity of the composite was investigated. Based on the results obtained, a discussion was carried out on the type of conductivity characteristic of silicone with different filler content as well as depending on the level of deformation of the samples.
</abstract>

Impact of Carbon Nanotubes on the Mechanical and Electrical Properties of Silicone

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Fatigue of Aircraft Structures

 Print ISSN - 2081-7738Online ISSN - 2300-7591   The primary version of the journal is the online one.   Based on the decision of the Minister of Science of January 5, 2024, 40 points are awarded to the academic achievement for the scientific articles published in the journal.   The publication focuses on problems of aeronautical fatigue and structural integrity. The preferred topics include:    full-scale fatigue testing of aircraft and aircraft structural components,   fatigue of materials and structures,   advanced materials and innovative structural concepts,   damage tolerant design of aircraft structure,   life extension and management of ageing fleets,   structural health monitoring and loads,   fatigue crack growth and life prediction methods,   NDT inspections,   airworthiness considerations.        Why subscribe and read   Because, it gives information on recent works from the area of fatigue of aircraft structures. A lot of works are presented by domestic and worldwide researchers.   Why submit   Because, it gives you a chance for presentation your own works. Publication once a year. No publication charge.   Archiving   Sciendo archives the contents of this journal in Portico - digital long-term preservation service of scholarly books, journals and collections.   Plagiarism Policy   The editorial board is participating in a growing community of Similarity Check System's users in order to ensure that the content published is original and trustworthy. Similarity Check is a medium that allows for comprehensive manuscripts screening, aimed to eliminate plagiarism and provide a high standard and quality peer-review process. 