Papers by Grzegorz Moneta
Fatigue of Aircraft Structures
Blade vibrations in aircraft engines are a significant challenge that must be overcome during the... more 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.
Fatigue of Aircraft Structures, Dec 1, 2021
Refill Friction Stir Spot Welding (RFSSW) is a technology used for joining solid materials that w... more Refill Friction Stir Spot Welding (RFSSW) is a technology used for joining solid materials that was developed in Germany in 2002 by GKSS-GmbH as a variant of the conventional friction stir spot welding (FSSW) [1]. In the RFSSW technology, the welding tool consists of a fixed outer part and rotating inner parts, which are called a pin and a sleeve. The tool for RFSSW is designed to plasticize the material of the parts to be joined by means of a rotary movement. The design of the tool allows independent vertical movement of both elements of the welding tool. This allows obtaining spot welds without creating holes that could weaken the structure. The main advantage of RFSSW is the potential for replacing the technologies that add weight to the structure or create discontinuities, such as joining with screws or rivets. Thus, RFSSW has great potential in the automotive, shipbuilding and aviation industries. Furthermore, the technology can be used to join different materials that could not be connected using other joining methods. The main objective of this work is to understand the physical and mechanical aspects of the RFSSW method-including the residual stress state inside the weld and around the joint. The results of the investigations can help to determine optimal parameters that could increase the strength and fatigue performance of the joint and to prove the significant advantage of RFSSW connections over other types of joints. The work assumes the correlation of two mutually complementary investigation methods: numerical analyses and experimental studies carried out with diffraction methods. The comparison between numerical and experimental results makes potentially possible the determination of degree of fatigue degradation of the material by observing the macroscopic stress state and the broadening of the diffraction peak width (FWHM), which is an indicator of the existence of micro-stress related to the dislocation density and grain size.
Fatigue of Aircraft Structures, Dec 1, 2021
The greatest challenge of widely developed incremental manufacturing methods today is to obtain, ... more The greatest challenge of widely developed incremental manufacturing methods today is to obtain, as a result of the manufacturing process, such components that will have acceptable strength properties from the point of view of a given application. These properties are indirectly determined by three key characteristics: the level of surface residual stress, the roughness of the component and its porosity. Currently, the efforts of many research groups are focused on the problem of optimizing the parameters of incremental manufacturing so as to achieve the appropriate level of compressive residual stress, the lowest possible porosity and the lowest possible roughness of parts obtained by 3D methods. It is now recognized that determining the level of these three parameters is potentially possible using experimental X-ray diffraction methods. The use of this type of radiation, admittedly, is only used to characterize the surface layer of elements, but its undoubted advantage is its easy availability and relatively low cost compared to experiments carried out using synchrotron or neutron radiation.
Machine Dynamics Research, 2014
High Cycle Fatigue is one of most common mechanism of turbine blade failures. The reason are vibr... more High Cycle Fatigue is one of most common mechanism of turbine blade failures. The reason are vibrations, which cause cyclic displacements and though that also variable stresses and strains. The most dangerous are excitation frequencies around resonances – that can cause failure in a very short time. About 70 years of jet engine development and more than one century of steam turbine history, was not enough to fully eliminate that problem. This paper shows an influence of manufacturing tolerances and accuracy of manufacturing technology on blade frequencies. Additionally, few methods for avoiding resonances have been presented and its implementation effort have been compared.
Fatigue of Aircraft Structures, Dec 1, 2021
Despite of nearly 100 years of turbine engine development and design, blade vibrations remain a g... more Despite of nearly 100 years of turbine engine development and design, blade vibrations remain a great engineering challenge. The rotating turbine blades' vibrations lead to cyclic oscillations, which result in alternating stress and strain in harsh environments of high temperature and pressure. In modern aeroengines, high hot flow velocities might generate erosion and corrosion pitting on the metal surfaces, that leverage remarkably mean stresses. The combination of both mean and alternating stresses can lead to unexpected engine failures, especially under resonance conditions. Then, alternating stress amplitudes can exceed the safety endurance limit, what accelerates the high cyclic fatigue leading quickly to catastrophic failure of the blade. Concerning the existing state-of-the-art and new market demands, this paper revises forced vibrations with respect to excitation mechanisms related to three design levels: (i) a component like the blade design, (ii) turbine stage design consisting of vanes and blades and (iii) a system design of a combustor and turbine. This work reviews the best practices for preventing the crotating turbine and compressor blades from High Cyclic Fatigue in the design process. Finally, an engine commissioning is briefly weighed up all the pros and cons to the experimental validations and needed measuring equipment.
Challenges to national defence in contemporary geopolitical situation, Oct 31, 2022
The most notable machines that currently have the impact of eliminating humans from direct contac... more The most notable machines that currently have the impact of eliminating humans from direct contact with the enemy are various types of remotely controlled or autonomous drones. They wreak havoc and fear in the enemy camp, significantly affecting the outcome of current conflicts. The fact of increasing the advantage in the attack causes the need for adequate defense or rescue measures. Thus, the use of remote-controlled drones for rescue/medical purposes seems a natural or even necessary path for the development of military technology. The described drone is intended to be unmanned, designed to transport only one injured person to be evacuated from an area of intense combat with the usage of an onboard robot. It is intended that the drone will be electrically powered which will reduce the possibility of detection due to acoustic and heat signature.
Fatigue of Aircraft Structures, Dec 1, 2021
Methods of incremental manufacturing, i.e. 3D printing, have been experiencing significant growth... more Methods of incremental manufacturing, i.e. 3D printing, have been experiencing significant growth in recent years, both in terms of the development of modern technologies dedicated to various applications, and in terms of optimizing the parameters of the process itself so as to ensure the desired mechanical and strength properties of the parts produced in this way. High hopes are currently being pinned on the use of highly penetrating types of radiation, i.e. synchrotron and/or neutron radiation, for quantitative identification of parameters characterizing objects produced by means of 3D printing. Thanks to diffraction methodologies, it is feasible to obtain input information to optimize 3D printing procedures not only for finished prints but also to monitor in situ printing processes. Thanks to these methodologies, it is possible to obtain information on parameters that are critical from the perspective of application of such obtained elements as stresses generated during the printing procedure itself as well as residual stresses after printing. This parameter, from the point of view of tensile strength, compression strength as well as fatigue strength, is crucial and determines the possibility of introducing elements produced by incremental methods into widespread industrial use.
Fatigue of Aircraft Structures, Dec 1, 2017
The motivation of the article is fatigue and fretting issue of the compressor rotor blades and di... more The motivation of the article is fatigue and fretting issue of the compressor rotor blades and disks. These phenomena can be caused by high contact pressures leading to fretting occurring on contact faces in the lock (blade-disk connection, attachment of the blade to the disk). Additionally, geometrical notches and high cyclic loading can initiate cracks and lead to engine failures. The paper presents finite element static and modal analyses of the axial compressor 3 rd rotor stage (disk and blades) of the K-15 turbine engine. The analyses were performed for the original trapezoidal/dovetail lock geometry and its two modifications (new lock concepts) to optimize the stress state of the disk-blade assembly. The cyclic symmetry formulation was used to reduce modelling and computational effort.
Challenges to national defence in contemporary geopolitical situation
The most notable machines that currently have the impact of eliminating humans from direct contac... more The most notable machines that currently have the impact of eliminating humans from direct contact with the enemy are various types of remotely controlled or autonomous drones. They wreak havoc and fear in the enemy camp, significantly affecting the outcome of current conflicts. The fact of increasing the advantage in the attack causes the need for adequate defense or rescue measures. Thus, the use of remote-controlled drones for rescue/medical purposes seems a natural or even necessary path for the development of military technology. The described drone is intended to be unmanned, designed to transport only one injured person to be evacuated from an area of intense combat with the usage of an onboard robot. It is intended that the drone will be electrically powered which will reduce the possibility of detection due to acoustic and heat signature.
Fatigue of Aircraft Structures
Methods of incremental manufacturing, i.e. 3D printing, have been experiencing significant growth... more Methods of incremental manufacturing, i.e. 3D printing, have been experiencing significant growth in recent years, both in terms of the development of modern technologies dedicated to various applications, and in terms of optimizing the parameters of the process itself so as to ensure the desired mechanical and strength properties of the parts produced in this way. High hopes are currently being pinned on the use of highly penetrating types of radiation, i.e. synchrotron and/or neutron radiation, for quantitative identification of parameters characterizing objects produced by means of 3D printing. Thanks to diffraction methodologies, it is feasible to obtain input information to optimize 3D printing procedures not only for finished prints but also to monitor in situ printing processes. Thanks to these methodologies, it is possible to obtain information on parameters that are critical from the perspective of application of such obtained elements as stresses generated during the print...
Fatigue of Aircraft Structures
Refill Friction Stir Spot Welding (RFSSW) is a technology used for joining solid materials that w... more Refill Friction Stir Spot Welding (RFSSW) is a technology used for joining solid materials that was developed in Germany in 2002 by GKSS-GmbH as a variant of the conventional friction stir spot welding (FSSW) [1]. In the RFSSW technology, the welding tool consists of a fixed outer part and rotating inner parts, which are called a pin and a sleeve. The tool for RFSSW is designed to plasticize the material of the parts to be joined by means of a rotary movement. The design of the tool allows independent vertical movement of both elements of the welding tool. This allows obtaining spot welds without creating holes that could weaken the structure. The main advantage of RFSSW is the potential for replacing the technologies that add weight to the structure or create discontinuities, such as joining with screws or rivets. Thus, RFSSW has great potential in the automotive, shipbuilding and aviation industries. Furthermore, the technology can be used to join different materials that could no...
Fatigue of Aircraft Structures
The greatest challenge of widely developed incremental manufacturing methods today is to obtain, ... more The greatest challenge of widely developed incremental manufacturing methods today is to obtain, as a result of the manufacturing process, such components that will have acceptable strength properties from the point of view of a given application. These properties are indirectly determined by three key characteristics: the level of surface residual stress, the roughness of the component and its porosity. Currently, the efforts of many research groups are focused on the problem of optimizing the parameters of incremental manufacturing so as to achieve the appropriate level of compressive residual stress, the lowest possible porosity and the lowest possible roughness of parts obtained by 3D methods. It is now recognized that determining the level of these three parameters is potentially possible using experimental X-ray diffraction methods. The use of this type of radiation, admittedly, is only used to characterize the surface layer of elements, but its undoubted advantage is its easy...
Fatigue of Aircraft Structures
Despite of nearly 100 years of turbine engine development and design, blade vibrations remain a g... more Despite of nearly 100 years of turbine engine development and design, blade vibrations remain a great engineering challenge. The rotating turbine blades’ vibrations lead to cyclic oscillations, which result in alternating stress and strain in harsh environments of high temperature and pressure. In modern aeroengines, high hot flow velocities might generate erosion and corrosion pitting on the metal surfaces, that leverage remarkably mean stresses. The combination of both mean and alternating stresses can lead to unexpected engine failures, especially under resonance conditions. Then, alternating stress amplitudes can exceed the safety endurance limit, what accelerates the high cyclic fatigue leading quickly to catastrophic failure of the blade. Concerning the existing state-of-the-art and new market demands, this paper revises forced vibrations with respect to excitation mechanisms related to three design levels: (i) a component like the blade design, (ii) turbine stage design consi...
Machine Dynamics Research, 2014
High Cycle Fatigue is one of most common mechanism of turbine blade failures. The reason are vibr... more High Cycle Fatigue is one of most common mechanism of turbine blade failures. The reason are vibrations, which cause cyclic displacements and though that also variable stresses and strains. The most dangerous are excitation frequencies around resonances – that can cause failure in a very short time. About 70 years of jet engine development and more than one century of steam turbine history, was not enough to fully eliminate that problem. This paper shows an influence of manufacturing tolerances and accuracy of manufacturing technology on blade frequencies. Additionally, few methods for avoiding resonances have been presented and its implementation effort have been compared.
ilot.edu.pl
36 ZJAWISKO FRETTINGU W KONSTRUKCJACH LOTNICZYCH Jerzy Jachimowicz, Piotr Kozłowski, Grzegorz Mon... more 36 ZJAWISKO FRETTINGU W KONSTRUKCJACH LOTNICZYCH Jerzy Jachimowicz, Piotr Kozłowski, Grzegorz Moneta, Elżbieta Szymczyk Wojskowa Akademia Techniczna Jerzy Kaniowski Instytut Lotnictwa Streszczenie Zmęczenie cierne często jest przyczyną przedwczesnego ...
Fatigue of Aircraft Structures, 2017
The motivation of the article is fatigue and fretting issue of the compressor rotor blades and di... more The motivation of the article is fatigue and fretting issue of the compressor rotor blades and disks. These phenomena can be caused by high contact pressures leading to fretting occurring on contact faces in the lock (blade-disk connection, attachment of the blade to the disk). Additionally, geometrical notches and high cyclic loading can initiate cracks and lead to engine failures. The paper presents finite element static and modal analyses of the axial compressor 3rd rotor stage (disk and blades) of the K-15 turbine engine. The analyses were performed for the original trapezoidal/dovetail lock geometry and its two modifications (new lock concepts) to optimize the stress state of the disk-blade assembly. The cyclic symmetry formulation was used to reduce modelling and computational effort.
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Papers by Grzegorz Moneta