Adam Martowicz | AGH University of Science and Technology (original) (raw)

Papers by Adam Martowicz

Research paper thumbnail of Thermal Characterization of a Gas Foil Bearing—A Novel Method of Experimental Identification of the Temperature Field Based on Integrated Thermocouples Measurements

Sensors

Maintenance of adequate thermal properties is critical for correct operation of a gas foil bearin... more Maintenance of adequate thermal properties is critical for correct operation of a gas foil bearing. In this work, the authors present the results of the experimentally conducted thermal characterization of a prototype installation of the bearing. A novel method of temperature identification, based on integrated thermocouples readings, has been employed to determine the thermal properties of the specialized sensing top foil mounted in the tested bearing. Two measurement campaigns have been subsequently completed, applying freely-suspended and two-node support configurations, to gather complementary knowledge regarding the bearing’s operation. Apart from the rotational speed and temperature field measurements, the authors have also studied the friction torque and the shaft’s journal trajectories based on its radial displacements. The temporal courses for the above-mentioned quantities have enabled inference on the effects present during run-up, run-out and stable state operation at a ...

Research paper thumbnail of Thermal Characterization of a Gas Foil Bearing—A Novel Method of Experimental Identification of the Temperature Field Based on Integrated Thermocouples Measurements

Sensors

Maintenance of adequate thermal properties is critical for correct operation of a gas foil bearin... more Maintenance of adequate thermal properties is critical for correct operation of a gas foil bearing. In this work, the authors present the results of the experimentally conducted thermal characterization of a prototype installation of the bearing. A novel method of temperature identification, based on integrated thermocouples readings, has been employed to determine the thermal properties of the specialized sensing top foil mounted in the tested bearing. Two measurement campaigns have been subsequently completed, applying freely-suspended and two-node support configurations, to gather complementary knowledge regarding the bearing’s operation. Apart from the rotational speed and temperature field measurements, the authors have also studied the friction torque and the shaft’s journal trajectories based on its radial displacements. The temporal courses for the above-mentioned quantities have enabled inference on the effects present during run-up, run-out and stable state operation at a ...

Research paper thumbnail of Uncertainty propagation for vehicle detections in experimentally validated radar model for automotive application

2019 24th International Conference on Methods and Models in Automation and Robotics (MMAR)

The paper is devoted to the development and experimental validation of a radar model elaborated f... more The paper is devoted to the development and experimental validation of a radar model elaborated for an automotive application. The described numerical model takes into account the physical properties of a typical automotive radar, the environmental conditions as well as the properties of targeted objects. Moreover, a dedicated, very efficient algorithm of geometric transformations - implemented in the radar model for simulation of wave scattering phenomena - is presented. A phenomenological model of uncertainty is enclosed to the algorithm to represent more effectively radar detections. The solution presented by the authors is thus ready to be used in hardware-in-the-loop simulations of various road traffic scenarios.

Research paper thumbnail of Gas Foil Bearing Technology Enhanced with Smart Materials

Applied Sciences

The paper discusses a perspective of the usage of various types of smart materials to enhance the... more The paper discusses a perspective of the usage of various types of smart materials to enhance the operational properties of Gas Foil Bearings. The authors, referring to the current investigation on thermomechanical characteristics of the above-mentioned bearing type, have focused on the concept of using Shape Memory Alloys, Piezoelectric Transducers, Thermoelectric Modules and Thermocouples to improve both mechanical and thermal behavior of the bearings. Based on the available literature and the authors’ experience, the present work provides an overview of the known and perspective applications of smart materials to Gas Foil Bearings. In particular, a discussion on their capabilities, limitations and effectiveness is conducted, taking into account the unique characteristics and requirements of the studied type of bearings.

Research paper thumbnail of Gas Foil Bearing Technology Enhanced with Smart Materials

Applied Sciences

The paper discusses a perspective of the usage of various types of smart materials to enhance the... more The paper discusses a perspective of the usage of various types of smart materials to enhance the operational properties of Gas Foil Bearings. The authors, referring to the current investigation on thermomechanical characteristics of the above-mentioned bearing type, have focused on the concept of using Shape Memory Alloys, Piezoelectric Transducers, Thermoelectric Modules and Thermocouples to improve both mechanical and thermal behavior of the bearings. Based on the available literature and the authors’ experience, the present work provides an overview of the known and perspective applications of smart materials to Gas Foil Bearings. In particular, a discussion on their capabilities, limitations and effectiveness is conducted, taking into account the unique characteristics and requirements of the studied type of bearings.

Research paper thumbnail of Phase transformation in shape memory alloys: a numerical approach for thermomechanical modeling via peridynamics

Meccanica

The work is devoted to the numerical aspects of the modeling tool elaborated to simulate the phen... more The work is devoted to the numerical aspects of the modeling tool elaborated to simulate the phenomenon of solid phase transformation in shape memory alloys. Particularly, a nonlocal approach, namely the bond based variant of peridynamics, is of concern to handle material model nonlinearities conveniently. The proposed model considers thermomechanical coupling which governs kinetics of the process of phase change. The phenomenological peridynamic model of a shape memory alloy is based on the Gibbs free energy concept and thermoelasticity. The work focuses on the superelasticity effect which can be observed when a tested material is subjected to a mechanical load. As a demanded application scope for the proposed smart material model, its scheduled future use in the study of operational conditions for a gas foil bearing is considered. The motivation of the work has primarily originated from the perspective of more accurate, i.e., more physical, modeling of the structural components which employ shape memory alloys to stabilize the bearing operation. The authors conduct a preliminary investigation regarding the properties of the newly proposed numerical multiphysics approach. Specifically, the scope of the work covers description of the developed computational framework as well as detailed derivation of its stability criteria. Exemplary numerical results complement the paper providing with determination of the stress–strain relation and adequate parametric study.

Research paper thumbnail of Phase transformation in shape memory alloys: a numerical approach for thermomechanical modeling via peridynamics

Meccanica

The work is devoted to the numerical aspects of the modeling tool elaborated to simulate the phen... more The work is devoted to the numerical aspects of the modeling tool elaborated to simulate the phenomenon of solid phase transformation in shape memory alloys. Particularly, a nonlocal approach, namely the bond based variant of peridynamics, is of concern to handle material model nonlinearities conveniently. The proposed model considers thermomechanical coupling which governs kinetics of the process of phase change. The phenomenological peridynamic model of a shape memory alloy is based on the Gibbs free energy concept and thermoelasticity. The work focuses on the superelasticity effect which can be observed when a tested material is subjected to a mechanical load. As a demanded application scope for the proposed smart material model, its scheduled future use in the study of operational conditions for a gas foil bearing is considered. The motivation of the work has primarily originated from the perspective of more accurate, i.e., more physical, modeling of the structural components which employ shape memory alloys to stabilize the bearing operation. The authors conduct a preliminary investigation regarding the properties of the newly proposed numerical multiphysics approach. Specifically, the scope of the work covers description of the developed computational framework as well as detailed derivation of its stability criteria. Exemplary numerical results complement the paper providing with determination of the stress–strain relation and adequate parametric study.

Research paper thumbnail of Multi-domain approach to modeling pantograph-catenary interaction

Eksploatacja i Niezawodnosc - Maintenance and Reliability

When a railway pantograph interacts with a catenary during the movement of a rail vehicle, severa... more When a railway pantograph interacts with a catenary during the movement of a rail vehicle, several physical phenomena, both mechanical and electrical, occur in the system. These phenomena affect the quality of power supply of a train from traction devices. The unfavourable arcing occurring when there are disturbances of contact between the pantograph’s slider and the catenary contact wire. In turn, it results in energy loss and increased wear of the components of the system. When designing new solutions, computational models are helpful to predict the quality of interaction between the components of the pantograph-contact line system already at the virtual prototyping stage. In this paper, the authors comprehensively present a multi-domain (multiphysics) model, which takes into account necessary conditions for interaction between pantograph elements and a catenary. Finally, the impact of the individual physical domains are analysed and the ones which have a significant impact on the...

Research paper thumbnail of Multi-domain approach to modeling pantograph-catenary interaction

Eksploatacja i Niezawodnosc - Maintenance and Reliability

When a railway pantograph interacts with a catenary during the movement of a rail vehicle, severa... more When a railway pantograph interacts with a catenary during the movement of a rail vehicle, several physical phenomena, both mechanical and electrical, occur in the system. These phenomena affect the quality of power supply of a train from traction devices. The unfavourable arcing occurring when there are disturbances of contact between the pantograph’s slider and the catenary contact wire. In turn, it results in energy loss and increased wear of the components of the system. When designing new solutions, computational models are helpful to predict the quality of interaction between the components of the pantograph-contact line system already at the virtual prototyping stage. In this paper, the authors comprehensively present a multi-domain (multiphysics) model, which takes into account necessary conditions for interaction between pantograph elements and a catenary. Finally, the impact of the individual physical domains are analysed and the ones which have a significant impact on the...

Research paper thumbnail of Improving Capabilities of Constitutive Modeling of Shape Memory Alloys for Solving Dynamic Problems Via Application of Neural Networks

Springer Proceedings in Mathematics & Statistics, 2022

Research paper thumbnail of Zastosowanie sytemu rozproszonego do wspomagania optymalizacji złożonych konstrukcji mechanicznych

Research paper thumbnail of Improving Capabilities of Constitutive Modeling of Shape Memory Alloys for Solving Dynamic Problems Via Application of Neural Networks

Springer Proceedings in Mathematics & Statistics, 2022

Research paper thumbnail of MARTOWICZ , ROSIEK , UHL , SHM system based on impedance measurements 3 SHM SYSTEM BASED ON IMPEDANCE MEASUREMENTS

The paper presents the results of laboratory testing procedure applied for the SHM system develop... more The paper presents the results of laboratory testing procedure applied for the SHM system developed at AGH-UST Department of Robotics and Mechatronics, Poland. Experimental setup has allowed for the measurement of electromechanical impedance with piezoelectric transducers bonded on an aluminum panel. In the paper there are presented the principle of nondestructive testing based on the impedance measurement, the description of developed SHM system and the results of performed experiments. It is shown how local changes introduced into the panel properties influence measured electromechanical impedance.

Research paper thumbnail of Zastosowanie sytemu rozproszonego do wspomagania optymalizacji złożonych konstrukcji mechanicznych

Research paper thumbnail of MARTOWICZ , ROSIEK , UHL , SHM system based on impedance measurements 3 SHM SYSTEM BASED ON IMPEDANCE MEASUREMENTS

The paper presents the results of laboratory testing procedure applied for the SHM system develop... more The paper presents the results of laboratory testing procedure applied for the SHM system developed at AGH-UST Department of Robotics and Mechatronics, Poland. Experimental setup has allowed for the measurement of electromechanical impedance with piezoelectric transducers bonded on an aluminum panel. In the paper there are presented the principle of nondestructive testing based on the impedance measurement, the description of developed SHM system and the results of performed experiments. It is shown how local changes introduced into the panel properties influence measured electromechanical impedance.

Research paper thumbnail of Numerical identification of the dynamic characteristics of a nonlinear foil bearing structure: Effect of the excitation force amplitude and the assembly preload

Journal of Sound and Vibration, 2021

Research paper thumbnail of Numerical identification of the dynamic characteristics of a nonlinear foil bearing structure: Effect of the excitation force amplitude and the assembly preload

Journal of Sound and Vibration, 2021

Research paper thumbnail of Study on the temperature and strain fields in gas foil bearings – measurement method and numerical simulations

Eksploatacja i Niezawodnosc - Maintenance and Reliability, 2021

Gas foil bearings belong to the group of slide bearings and are used in devices in which operatio... more Gas foil bearings belong to the group of slide bearings and are used in devices in which operation at high rotational speeds of the shafts are of key importance, e.g., in gas turbines. The air film developed on the surface of the bearing’s top foil allows this structural component to be separated from the shaft. This ensures a non-contact operation of the bearing. In the case of the mentioned type of bearings, their resultant operational properties are influenced by both thermal and mechanical phenomena. The current work presents a model of a gas foil bearing developed making use of the Finite Element Method. The model takes into account thermomechanical couplings which are necessary for the correct simulation of the operation of physical components of the modeled system. The paper reports the results of numerical analyzes conducted for the elaborated model as well as the relevant conclusions concerning thermomechanical couplings present in gas foil bearings. The method for the expe...

Research paper thumbnail of Study on the temperature and strain fields in gas foil bearings – measurement method and numerical simulations

Eksploatacja i Niezawodnosc - Maintenance and Reliability, 2021

Gas foil bearings belong to the group of slide bearings and are used in devices in which operatio... more Gas foil bearings belong to the group of slide bearings and are used in devices in which operation at high rotational speeds of the shafts are of key importance, e.g., in gas turbines. The air film developed on the surface of the bearing’s top foil allows this structural component to be separated from the shaft. This ensures a non-contact operation of the bearing. In the case of the mentioned type of bearings, their resultant operational properties are influenced by both thermal and mechanical phenomena. The current work presents a model of a gas foil bearing developed making use of the Finite Element Method. The model takes into account thermomechanical couplings which are necessary for the correct simulation of the operation of physical components of the modeled system. The paper reports the results of numerical analyzes conducted for the elaborated model as well as the relevant conclusions concerning thermomechanical couplings present in gas foil bearings. The method for the expe...

Research paper thumbnail of Study on the Importance of a Slicer Selection for the 3D Printing Process Parameters via the Investigation of G-Code Readings

Machines, 2021

The work deals with the investigation of the variation of the selected 3D printing process proper... more The work deals with the investigation of the variation of the selected 3D printing process properties that originate from the choice of a slicer. Specifically, the main aim of the present study was to assess the induced changes of the kinematic and geometric properties considered by the slicer for the printing process making use of the G-code readings. The paper provides adequate definitions and formulas required to characterize the slicer’s configuration. Next, the selected cases of the process parameters’ changes were studied, primarily taking into account varying layer height and infill. The authors performed a detailed analysis regarding the geometric implications at the mesoscale due to the slicer’s settings. Appropriate modifications of the slicer’s properties were also proposed and verified, making it possible to match the geometric and kinematic characteristics of the printed part.

Research paper thumbnail of Thermal Characterization of a Gas Foil Bearing—A Novel Method of Experimental Identification of the Temperature Field Based on Integrated Thermocouples Measurements

Sensors

Maintenance of adequate thermal properties is critical for correct operation of a gas foil bearin... more Maintenance of adequate thermal properties is critical for correct operation of a gas foil bearing. In this work, the authors present the results of the experimentally conducted thermal characterization of a prototype installation of the bearing. A novel method of temperature identification, based on integrated thermocouples readings, has been employed to determine the thermal properties of the specialized sensing top foil mounted in the tested bearing. Two measurement campaigns have been subsequently completed, applying freely-suspended and two-node support configurations, to gather complementary knowledge regarding the bearing’s operation. Apart from the rotational speed and temperature field measurements, the authors have also studied the friction torque and the shaft’s journal trajectories based on its radial displacements. The temporal courses for the above-mentioned quantities have enabled inference on the effects present during run-up, run-out and stable state operation at a ...

Research paper thumbnail of Thermal Characterization of a Gas Foil Bearing—A Novel Method of Experimental Identification of the Temperature Field Based on Integrated Thermocouples Measurements

Sensors

Maintenance of adequate thermal properties is critical for correct operation of a gas foil bearin... more Maintenance of adequate thermal properties is critical for correct operation of a gas foil bearing. In this work, the authors present the results of the experimentally conducted thermal characterization of a prototype installation of the bearing. A novel method of temperature identification, based on integrated thermocouples readings, has been employed to determine the thermal properties of the specialized sensing top foil mounted in the tested bearing. Two measurement campaigns have been subsequently completed, applying freely-suspended and two-node support configurations, to gather complementary knowledge regarding the bearing’s operation. Apart from the rotational speed and temperature field measurements, the authors have also studied the friction torque and the shaft’s journal trajectories based on its radial displacements. The temporal courses for the above-mentioned quantities have enabled inference on the effects present during run-up, run-out and stable state operation at a ...

Research paper thumbnail of Uncertainty propagation for vehicle detections in experimentally validated radar model for automotive application

2019 24th International Conference on Methods and Models in Automation and Robotics (MMAR)

The paper is devoted to the development and experimental validation of a radar model elaborated f... more The paper is devoted to the development and experimental validation of a radar model elaborated for an automotive application. The described numerical model takes into account the physical properties of a typical automotive radar, the environmental conditions as well as the properties of targeted objects. Moreover, a dedicated, very efficient algorithm of geometric transformations - implemented in the radar model for simulation of wave scattering phenomena - is presented. A phenomenological model of uncertainty is enclosed to the algorithm to represent more effectively radar detections. The solution presented by the authors is thus ready to be used in hardware-in-the-loop simulations of various road traffic scenarios.

Research paper thumbnail of Gas Foil Bearing Technology Enhanced with Smart Materials

Applied Sciences

The paper discusses a perspective of the usage of various types of smart materials to enhance the... more The paper discusses a perspective of the usage of various types of smart materials to enhance the operational properties of Gas Foil Bearings. The authors, referring to the current investigation on thermomechanical characteristics of the above-mentioned bearing type, have focused on the concept of using Shape Memory Alloys, Piezoelectric Transducers, Thermoelectric Modules and Thermocouples to improve both mechanical and thermal behavior of the bearings. Based on the available literature and the authors’ experience, the present work provides an overview of the known and perspective applications of smart materials to Gas Foil Bearings. In particular, a discussion on their capabilities, limitations and effectiveness is conducted, taking into account the unique characteristics and requirements of the studied type of bearings.

Research paper thumbnail of Gas Foil Bearing Technology Enhanced with Smart Materials

Applied Sciences

The paper discusses a perspective of the usage of various types of smart materials to enhance the... more The paper discusses a perspective of the usage of various types of smart materials to enhance the operational properties of Gas Foil Bearings. The authors, referring to the current investigation on thermomechanical characteristics of the above-mentioned bearing type, have focused on the concept of using Shape Memory Alloys, Piezoelectric Transducers, Thermoelectric Modules and Thermocouples to improve both mechanical and thermal behavior of the bearings. Based on the available literature and the authors’ experience, the present work provides an overview of the known and perspective applications of smart materials to Gas Foil Bearings. In particular, a discussion on their capabilities, limitations and effectiveness is conducted, taking into account the unique characteristics and requirements of the studied type of bearings.

Research paper thumbnail of Phase transformation in shape memory alloys: a numerical approach for thermomechanical modeling via peridynamics

Meccanica

The work is devoted to the numerical aspects of the modeling tool elaborated to simulate the phen... more The work is devoted to the numerical aspects of the modeling tool elaborated to simulate the phenomenon of solid phase transformation in shape memory alloys. Particularly, a nonlocal approach, namely the bond based variant of peridynamics, is of concern to handle material model nonlinearities conveniently. The proposed model considers thermomechanical coupling which governs kinetics of the process of phase change. The phenomenological peridynamic model of a shape memory alloy is based on the Gibbs free energy concept and thermoelasticity. The work focuses on the superelasticity effect which can be observed when a tested material is subjected to a mechanical load. As a demanded application scope for the proposed smart material model, its scheduled future use in the study of operational conditions for a gas foil bearing is considered. The motivation of the work has primarily originated from the perspective of more accurate, i.e., more physical, modeling of the structural components which employ shape memory alloys to stabilize the bearing operation. The authors conduct a preliminary investigation regarding the properties of the newly proposed numerical multiphysics approach. Specifically, the scope of the work covers description of the developed computational framework as well as detailed derivation of its stability criteria. Exemplary numerical results complement the paper providing with determination of the stress–strain relation and adequate parametric study.

Research paper thumbnail of Phase transformation in shape memory alloys: a numerical approach for thermomechanical modeling via peridynamics

Meccanica

The work is devoted to the numerical aspects of the modeling tool elaborated to simulate the phen... more The work is devoted to the numerical aspects of the modeling tool elaborated to simulate the phenomenon of solid phase transformation in shape memory alloys. Particularly, a nonlocal approach, namely the bond based variant of peridynamics, is of concern to handle material model nonlinearities conveniently. The proposed model considers thermomechanical coupling which governs kinetics of the process of phase change. The phenomenological peridynamic model of a shape memory alloy is based on the Gibbs free energy concept and thermoelasticity. The work focuses on the superelasticity effect which can be observed when a tested material is subjected to a mechanical load. As a demanded application scope for the proposed smart material model, its scheduled future use in the study of operational conditions for a gas foil bearing is considered. The motivation of the work has primarily originated from the perspective of more accurate, i.e., more physical, modeling of the structural components which employ shape memory alloys to stabilize the bearing operation. The authors conduct a preliminary investigation regarding the properties of the newly proposed numerical multiphysics approach. Specifically, the scope of the work covers description of the developed computational framework as well as detailed derivation of its stability criteria. Exemplary numerical results complement the paper providing with determination of the stress–strain relation and adequate parametric study.

Research paper thumbnail of Multi-domain approach to modeling pantograph-catenary interaction

Eksploatacja i Niezawodnosc - Maintenance and Reliability

When a railway pantograph interacts with a catenary during the movement of a rail vehicle, severa... more When a railway pantograph interacts with a catenary during the movement of a rail vehicle, several physical phenomena, both mechanical and electrical, occur in the system. These phenomena affect the quality of power supply of a train from traction devices. The unfavourable arcing occurring when there are disturbances of contact between the pantograph’s slider and the catenary contact wire. In turn, it results in energy loss and increased wear of the components of the system. When designing new solutions, computational models are helpful to predict the quality of interaction between the components of the pantograph-contact line system already at the virtual prototyping stage. In this paper, the authors comprehensively present a multi-domain (multiphysics) model, which takes into account necessary conditions for interaction between pantograph elements and a catenary. Finally, the impact of the individual physical domains are analysed and the ones which have a significant impact on the...

Research paper thumbnail of Multi-domain approach to modeling pantograph-catenary interaction

Eksploatacja i Niezawodnosc - Maintenance and Reliability

When a railway pantograph interacts with a catenary during the movement of a rail vehicle, severa... more When a railway pantograph interacts with a catenary during the movement of a rail vehicle, several physical phenomena, both mechanical and electrical, occur in the system. These phenomena affect the quality of power supply of a train from traction devices. The unfavourable arcing occurring when there are disturbances of contact between the pantograph’s slider and the catenary contact wire. In turn, it results in energy loss and increased wear of the components of the system. When designing new solutions, computational models are helpful to predict the quality of interaction between the components of the pantograph-contact line system already at the virtual prototyping stage. In this paper, the authors comprehensively present a multi-domain (multiphysics) model, which takes into account necessary conditions for interaction between pantograph elements and a catenary. Finally, the impact of the individual physical domains are analysed and the ones which have a significant impact on the...

Research paper thumbnail of Improving Capabilities of Constitutive Modeling of Shape Memory Alloys for Solving Dynamic Problems Via Application of Neural Networks

Springer Proceedings in Mathematics & Statistics, 2022

Research paper thumbnail of Zastosowanie sytemu rozproszonego do wspomagania optymalizacji złożonych konstrukcji mechanicznych

Research paper thumbnail of Improving Capabilities of Constitutive Modeling of Shape Memory Alloys for Solving Dynamic Problems Via Application of Neural Networks

Springer Proceedings in Mathematics & Statistics, 2022

Research paper thumbnail of MARTOWICZ , ROSIEK , UHL , SHM system based on impedance measurements 3 SHM SYSTEM BASED ON IMPEDANCE MEASUREMENTS

The paper presents the results of laboratory testing procedure applied for the SHM system develop... more The paper presents the results of laboratory testing procedure applied for the SHM system developed at AGH-UST Department of Robotics and Mechatronics, Poland. Experimental setup has allowed for the measurement of electromechanical impedance with piezoelectric transducers bonded on an aluminum panel. In the paper there are presented the principle of nondestructive testing based on the impedance measurement, the description of developed SHM system and the results of performed experiments. It is shown how local changes introduced into the panel properties influence measured electromechanical impedance.

Research paper thumbnail of Zastosowanie sytemu rozproszonego do wspomagania optymalizacji złożonych konstrukcji mechanicznych

Research paper thumbnail of MARTOWICZ , ROSIEK , UHL , SHM system based on impedance measurements 3 SHM SYSTEM BASED ON IMPEDANCE MEASUREMENTS

The paper presents the results of laboratory testing procedure applied for the SHM system develop... more The paper presents the results of laboratory testing procedure applied for the SHM system developed at AGH-UST Department of Robotics and Mechatronics, Poland. Experimental setup has allowed for the measurement of electromechanical impedance with piezoelectric transducers bonded on an aluminum panel. In the paper there are presented the principle of nondestructive testing based on the impedance measurement, the description of developed SHM system and the results of performed experiments. It is shown how local changes introduced into the panel properties influence measured electromechanical impedance.

Research paper thumbnail of Numerical identification of the dynamic characteristics of a nonlinear foil bearing structure: Effect of the excitation force amplitude and the assembly preload

Journal of Sound and Vibration, 2021

Research paper thumbnail of Numerical identification of the dynamic characteristics of a nonlinear foil bearing structure: Effect of the excitation force amplitude and the assembly preload

Journal of Sound and Vibration, 2021

Research paper thumbnail of Study on the temperature and strain fields in gas foil bearings – measurement method and numerical simulations

Eksploatacja i Niezawodnosc - Maintenance and Reliability, 2021

Gas foil bearings belong to the group of slide bearings and are used in devices in which operatio... more Gas foil bearings belong to the group of slide bearings and are used in devices in which operation at high rotational speeds of the shafts are of key importance, e.g., in gas turbines. The air film developed on the surface of the bearing’s top foil allows this structural component to be separated from the shaft. This ensures a non-contact operation of the bearing. In the case of the mentioned type of bearings, their resultant operational properties are influenced by both thermal and mechanical phenomena. The current work presents a model of a gas foil bearing developed making use of the Finite Element Method. The model takes into account thermomechanical couplings which are necessary for the correct simulation of the operation of physical components of the modeled system. The paper reports the results of numerical analyzes conducted for the elaborated model as well as the relevant conclusions concerning thermomechanical couplings present in gas foil bearings. The method for the expe...

Research paper thumbnail of Study on the temperature and strain fields in gas foil bearings – measurement method and numerical simulations

Eksploatacja i Niezawodnosc - Maintenance and Reliability, 2021

Gas foil bearings belong to the group of slide bearings and are used in devices in which operatio... more Gas foil bearings belong to the group of slide bearings and are used in devices in which operation at high rotational speeds of the shafts are of key importance, e.g., in gas turbines. The air film developed on the surface of the bearing’s top foil allows this structural component to be separated from the shaft. This ensures a non-contact operation of the bearing. In the case of the mentioned type of bearings, their resultant operational properties are influenced by both thermal and mechanical phenomena. The current work presents a model of a gas foil bearing developed making use of the Finite Element Method. The model takes into account thermomechanical couplings which are necessary for the correct simulation of the operation of physical components of the modeled system. The paper reports the results of numerical analyzes conducted for the elaborated model as well as the relevant conclusions concerning thermomechanical couplings present in gas foil bearings. The method for the expe...

Research paper thumbnail of Study on the Importance of a Slicer Selection for the 3D Printing Process Parameters via the Investigation of G-Code Readings

Machines, 2021

The work deals with the investigation of the variation of the selected 3D printing process proper... more The work deals with the investigation of the variation of the selected 3D printing process properties that originate from the choice of a slicer. Specifically, the main aim of the present study was to assess the induced changes of the kinematic and geometric properties considered by the slicer for the printing process making use of the G-code readings. The paper provides adequate definitions and formulas required to characterize the slicer’s configuration. Next, the selected cases of the process parameters’ changes were studied, primarily taking into account varying layer height and infill. The authors performed a detailed analysis regarding the geometric implications at the mesoscale due to the slicer’s settings. Appropriate modifications of the slicer’s properties were also proposed and verified, making it possible to match the geometric and kinematic characteristics of the printed part.