Rafał Grzejda - Profile on Academia.edu (original) (raw)
Papers by Rafał Grzejda
Materials, 2025
The paper presents the effect of the symmetric and asymmetric semi-metallic gasket core shape on ... more The paper presents the effect of the symmetric and asymmetric semi-metallic gasket core shape on the tightness level in bolted flange joints. Experimental tests, as well as numerical calculations based on the finite element method, revealed that the asymmetric gasket core provides a higher strain on the sealing graphite layer and leads to a more uniform distribution of strain on the particular ridges of the core. Furthermore, the leakage rate of the asymmetric gasket was reduced by approximately 60% compared to the symmetric gasket. It was also observed that the uniformity of pressure and strain distribution in a gasket with an asymmetric core occurs over about 80% of the gasket width. The leakage reduction effect in a flange joint sealed with a gasket with an asymmetric core was theoretically explained. As shown, the main leakage flows through the porous structure of the graphite layer, while the leakage path at the interface between the metal rough profile and the graphite layer is several orders of magnitude smaller.
Coatings, 2025
Among the biggest challenges in modern manufacturing techniques is deliberately shaping the surfa... more Among the biggest challenges in modern manufacturing techniques is deliberately shaping the surface layer of a part to suit the conditions in which it will be used. The degree of difficulty increases with the increase in the functional requirements of the items to be manufactured and with the complexity of the technology developed. Hybrid machining processes allow functional surfaces to be shaped by combining different machining operations into a single operation. The values of the amplitude and length parameters of the resulting surface geometrical texture are largely determined by the technological parameters of the combined machining operations. However, it is the tool guidance and kinematic-geometric conditions during the hybrid machining process that are responsible for the surface texture. This paper describes the results of an investigation into the influence of the milling tool guidance strategy during shaping milling and tooling guidance during burnishing of workpieces made of 42CrMo4 steel tempered to a hardness of 35 ± 2 HRC-a material commonly used in the construction of machine parts. It was shown that running the burnishing with two crossing passes oriented obliquely to the marks left by the cutter was the most favourable of the burnishing strategies tested.
WSEAS transactions on applied and theoretical mechanics, Jun 22, 2023
Advances in Science and Technology Research Journal, 2025
This paper presents the results of model tests related to the process of forming a pipeline arch ... more This paper presents the results of model tests related to the process of forming a pipeline arch by mechanical mandrel bending. The problems that occur during the pipeline manufacturing process and the methods and instrumentation used in forming the bent section of a pipeline, in particular the so-called mandrel bending, are presented. The main part of the paper consists of the results of model tests of stresses and deformations arising from the process of forming the arc of a mechanically bent pipeline using the proposed version of the mandrel with a torus-shaped forming part. These studies included an analysis of the effect of the pre-positioning of the mandrel on the values of deformations and stresses occurring in the cross-section of the bent pipe arch as a function of changes in the wall thickness and external diameter of the pipe and the bending radius. Based on the test results obtained, criteria were established enabling the selected pipe bending method to be used so that the resulting stresses and dimensions in the cross-sections of the bent pipe section are within the limits imposed by the normative recommendations. It was also shown that the criterion determining the efficiency of the bending process is the allowable recommended value of the ovalisation of the pipe cross-section.
Materials, 2025
Fiber-reinforced composites are widely utilized across various industries, including aerospace, a... more Fiber-reinforced composites are widely utilized across various industries, including aerospace, automotive, and marine, due to their outstanding mechanical properties and lightweight characteristics. Natural fibers, as promising reinforcements, have the potential to replace synthetic fibers in certain areas to meet the growing demand for environmental protection and sustainability. These biocomposites offer numerous benefits, including reduced carbon footprints, diminished reliance on non-renewable resources, and increased natural biodegradability. In addition, utilizing such eco-friendly materials is a critical strategy for balancing industry progress and environmental protection. Kenaf fiber, a superior bast fiber known for its excellent mechanical properties and high cellulose content, presents considerable advantages for enhancing the performance of biocomposites. This review explores the potential of kenaf fiber-reinforced biocomposites for marine applications, focusing on their fabrication and testing methods to evaluate their physicochemical and mechanical properties. This paper examines the chemical composition and mechanical properties of the kenaf fiber, investigates the excellent performance advantages of kenaf fiber-based biocomposites by hybridization manufacturing, and provides an overview of the status and challenges of applying such biocomposites in marine environments. Based on this review, it is evident that kenaf fiber-reinforced biocomposites have significant superiority for marine applications with the advancement of manufacturing techniques.
WSEAS Transactions on Applied and Theoretical Mechanics, 2025
The paper presents a piece of research carried out on the development of modelling and calculatio... more The paper presents a piece of research carried out on the development of modelling and calculation methods for multi-bolted connections. The influence of the modelling of the separated bolted joint on the value of the working load in the bolt was considered. A stiffness analysis of the bolted joint for selected linear and non-linear models was carried out. Guidelines for the selection of the modelling method for the analysis of working loads occurring in a bolted joint are discussed.
TTS Technika Transportu Szynowego, 2014
Applied Sciences, 2025
The design process is a complex task in which different goals and properties have to be achieved.... more The design process is a complex task in which different goals and properties have to be achieved. Nowadays, end-of-life issues are increasingly being considered in addition to typical design properties such as durability, appearance or quality. This article presents the product design process in relation to its recycling and mechanical properties. A plate connection in two design versions was chosen as the product: in the form of a multi-bolted connection and a multi-riveted connection. An analysis was conducted for several vari-ants of these connections. Recycling properties were considered using various measures calculated from the Recycling Product Model, a type of product model that includes its re-cycling properties. Selected mechanical properties were determined using the Finite Ele-ment Method. Removing one bolt from the connection resulted in a stiffness reduction of almost 11%, while removing two bolts from the connection resulted in a stiffness reduction of almost 26%. In contrast, the removal of one rivet from the connection led to a stiffness reduction of about 3%, while the removal of two rivets from the connection led to a stiff-ness reduction of less than 5%.
Lubricants, 2024
Due to the need to form a surface layer with specific operating properties, recent years have see... more Due to the need to form a surface layer with specific operating properties, recent years have seen an increased interest in surface strengthening treatment, which aims to create a surface layer that improves the durability of parts. With a view to the economics of the machining process, it is common to combine shaping milling, characterised by high volu-metric efficiency, with finishing burnishing, during which significant forces are applied. In the literature, one of the important limitations of such technological operations is the value of residual stresses, excessive values of which can lead to the flaking and falling off of surface fragments. In the present study, the authors put forward the research hypothesis that, in addition to stresses, the geometry of the machining roughness is also important and may contribute to faster tribological wear than stresses. It has been shown that what is important in hybrid machining is not so much the height of the resulting irregularities and the effectiveness of their levelling by burnishing, but the geometry of the irregularities. Af-ter milling, surfaces with small, regular irregularities with smooth peaks and shallow val-leys were found to be the best in tribological tests. Such roughness can be plastically lev-elled out during burnishing. On the basis of the experimental studies carried out, it was shown that a higher burnishing force does not always lead to higher wear resistance.
Advances in Science and Technology Research Journal, 2025
The presented paper proposes a some concept of an evacuation drone that could pick up the wounded... more The presented paper proposes a some concept of an evacuation drone that could pick up the wounded from the battlefield and transport them to their final destination for adequate medical care. The existing state of the art of drones and their equipment is described, as well as the possibility of using current technology to build a new drone. This paper presents a vision of the ‘future/ideal drone’ and the ‘technically/reasonably achievable drone today’, and consequently the levels of its development. The main rationale for choosing a drone configuration, including the basic characteristic sizes, is discussed. In view of the purpose of the drone, i.e. need to perform basic medical activities, current robots used
in remote surgery were analysed. Due to the fact that the final version of the drone is to take up the wounded without the participation of a third party, design aspects related to this are presented and examples of solutions are proposed.
Metals, 2024
This study investigates the application of Phased Array Corrosion Mapping (PACM) as a non-destruc... more This study investigates the application of Phased Array Corrosion Mapping (PACM) as a non-destructive testing (NDT) method for detecting and monitoring corrosion growth on hot stainless steel (SS) surfaces, specifically focusing on SS 304 and SS 316. Conducted across a temperature range of 30 ◦C to 250 ◦C, the research evaluates the effectiveness of PACM in high-temperature environments typical of the petrochemical industry. Experiments were conducted using specimens with machined slots and flat-bottom holes (FBHs) to simulate corrosion defects. The results demonstrate that PACM effectively detects and maps corrosion indicators, with color-coded C-scan data facilitating easy
interpretation. Temperature variations significantly influenced ultrasound signal characteristics, leading to observable changes in FBH indications, particularly at elevated temperatures. Increased ultrasound attenuation necessitated adjustments in decibel settings to maintain accuracy. SS 304
and SS 316 exhibited distinct responses to temperature changes, with SS 316 showing higher dB values and unique signal behaviors, including increased scattering and noise echoes at elevated temperatures. Detected depths for slots and FBHs correlated closely with designed depths, with
deviations generally less than 0.5 mm; however, some instances showed deviations exceeding 2 mm, underscoring the need for careful interpretation. At temperatures above 230 ◦C, the disbanding
of probe elements led to weak or absent signals, complicating data interpretation and requiring adjustments in testing protocols. This study highlights the feasibility and effectiveness of PACM for corrosion detection on hot SS surfaces, providing critical insights into material behavior under thermal conditions. Future research should include physical examination of samples using Scanning Electron Microscopy (SEM) to validate and enhance the reliability of the findings. The integration of non-contact NDT methods and optimization of calibration techniques are essential for improving PACM performance at elevated temperatures.
Materials, 2024
Natural composites are emerging as promising alternative materials for 3D printing in biomedical ... more Natural composites are emerging as promising alternative materials for 3D printing in biomedical applications due to their biocompatibility, sustainability, and unique mechanical properties. The use of natural composites offers several advantages, including reduced environmental impact, enhanced biodegradability, and improved tissue compatibility. These materials can be processed into filaments or resins suitable for various 3D printing techniques, such as fused deposition modeling (FDM). Natural composites also exhibit inherent antibacterial properties, making them particularly suitable for applications in tissue engineering, drug delivery systems, and biomedical implants. This review explores the potential of utilizing natural composites in additive manu-facturing for biomedical purposes, discussing the historical development of 3D printing tech-niques, the types of manufacturing methods, and the optimization of material compatibility, printability, and mechanical properties to fully utilize the potential of using natural fibers in 3D printing for biomedical applications.
WSEAS Transactions on Applied and Theoretical Mechanics, 2024
Finite element modeling of multi-bolted foundation connections applied in the case of seating of ... more Finite element modeling of multi-bolted foundation connections applied in the case of seating of heavy machines or devices is reported. Connections performed by means of 3 different types of chocks were investigated. Characteristics of stiffness for the assumed models of multi-bolted foundation connections at the assembling phase were outlined and discussed. Conclusions of great relevance to engineering design were presented.
Materials, 2024
This paper presents a method for modelling the permeability of fluid at the interface formed betw... more This paper presents a method for modelling the permeability of fluid at the interface formed between flat parallel plates and the sharp-edged ridges of a metal gasket. This work was divided into three stages. In the first stage, numerical calculations simulating the deformation (compression of the gasket) were performed. The calculations were carried out using thermomechanical static analysis with commercial software. The purpose of these calculations was to determine the contact area of the gasket ridges with the plates, the deformation of the gasket ridges, and the reaction force resulting from the degree of compression of the gasket. In the second part of this work, analytical calculations were performed to estimate the tightness level. The analytical model proposed in this paper was based on Darcy's equation, simulating fluid flow through a ring-shaped porous layer. The analytical model also took into account the shape of the roughness profile of the sealed surfaces. A mathematical Ausloos-Berman function based on fractal theory was used to represent it. In the last part of this work, experimental tests were carried out to determine the actual fluid permeability and thus verify the numerical and analytical calculations.
Journal of Composites Science, 2024
Highly efficient fiber-reinforced composites find extensive application in diverse industries. Ye... more Highly efficient fiber-reinforced composites find extensive application in diverse industries. Yet, conventional fiber-reinforced composites have significant environmental impacts during both manufacturing and disposal. Environmentally friendly fiber-reinforced composites have garnered significant attention within the framework of sustainable development. Utilizing natural fibers in place of synthetic fibers and progressively decreasing the use of synthetic fibers are the main approaches to achieving a balance between economic progress and environmental quality. At-tention is increasingly being drawn to natural fiber-reinforced biocomposites that exhibit out-standing environmental performance, exceptional physical and mechanical capabilities, and bi-ological features. The lightweight and high-strength characteristics of these biocomposites enable them to significantly decrease the weight of structures, making them increasingly popular in many industries. The objective of this review is to evaluate the effectiveness of hybrid fiber-reinforced biocomposites in marine applications, specifically examining their mechanical characteristics, resistance to seawater, and ability to absorb moisture, all while advocating for sustainable ma-terial methodologies. To achieve this objective, the paper delineates the distinction between synthetic and natural fibers, examines the benefits of hybrid fiber-reinforced biocomposite ma-terials, and addresses the obstacles and effective approaches in their production and application in seawater. Considering the review analysis, it can be inferred that the use of fiber-reinforced bi-ocomposites in maritime applications shows significant potential and has abundant untapped growth prospects in the future years.
Applied Sciences, 2024
Modern technology allows ductile cast iron parts to be efficiently machined while ensuring a rela... more Modern technology allows ductile cast iron parts to be efficiently machined while ensuring a rela-tively long tool life. One of the basic indices describing the susceptibility of ductile cast irons to change in volume, shape, and dimensions under machining conditions is their machinability. Machinability can be expressed directly in terms of the values of basic quantities such as periodic cutting speed and roughness. At the same time, machinability is a relative quantity evaluated alternatively. This means that the machinability of ductile cast iron can be good, allowing high cutting speeds to be achieved, but it can also be poor, expressed in terms of poor surface quality. In the experimental research carried out, an attempt was made to determine the limit values of the cutting speed, beyond which one should not exceed, in order to increase the efficiency of the machining process. The surface roughness, unlike the periodic cutting speed, is a quantity defined in the product design docu-mentation, so its limits must be observed. In addition to the usual indices of surface geometric texture, the research analysed alternative indices for determining the condition of surface geometric texture and the influence of periodic cutting speed on their values. In the conclusions, valuable recommendations are given for designers and technologists on the purpose and functionality of product surfaces and how to define them. Methods of specifying tribological characteristics, hy-drophobic or hydrophilic properties, as well as the ability to retain fluids and maintain protective coatings of ductile cast iron parts after machining are described, for which relative values, depending on the machining parameters used, can vary from about 10 to even 30%.
Modelling, 2024
Finite element modelling of multi-bolted foundation connections used for the foundation of heavy ... more Finite element modelling of multi-bolted foundation connections used for the foundation of
heavy machinery or equipment is presented. Connections made using different types of shims, with
particular emphasis on polymer–steel shims, are investigated. The stiffness characteristics for the
adopted models of multi-bolted foundation connections at the installation stage are described and
compared. It is shown that the use of polymer–steel shims can result in a significant improvement in
the stiffness of a multi-bolted foundation connection compared to a connection with a polymer shim,
and in achieving a multi-bolted foundation connection with a stiffness similar to that of a connection
with a steel shim (at a sufficiently low polymer layer thickness).
Precision Engineering, 2024
The paper presents the procedures developed to correctly assess the geometric condition of large ... more The paper presents the procedures developed to correctly assess the geometric condition of large crankshafts using a novel measurement system equipped with a specially designed prism support system with computer monitoring of support reaction forces. These procedures were developed for three variants of measurement execution corresponding to conditions: non-referenced (fixing of the shaft to be measured with the outer extremes of the faces in the spherical prisms and supporting the shaft in the central part with a set of supports referred to as ‘elastic’), referenced (fixing of the shaft to be measured by the outer extremes of the main journals in prisms and support of the crankshaft in the central part, as in the case of the previous variant, by a set of supports referred to as ‘elastic’) and realised in conditions similar to the traditional ones (fixing and support of the crankshaft by a set of prism supports maintaining a constant height position). Considering the utilitarian potential of the developed procedures, exemplary applications of their practical use in the measurement of large crankshafts are presented.
Advances in Science and Technology Research Journal, 2024
The escalating global population and subsequent demand for agricultural products have led to a su... more The escalating global population and subsequent demand for agricultural products have led to a surge in agricultural waste generation, posing significant disposal challenges. Conventional disposal methods such as burning
and dumping not only harm the environment but also jeopardize human health and safety. Recognizing the urgent need for sustainable waste management, researchers have increasingly focused on repurposing agricultural
plant waste as a valuable resource. This paper presents a comprehensive review of the potential of agricultural
plant waste in wealth creation and sustainable development. It highlights the detrimental impacts of current
disposal methods and emphasizes the necessity for alternative approaches. By analyzing the physical, mechanical, and chemical properties of plant fibers, particularly cellulose, hemicellulose, and lignin, this review underscores their suitability for diverse applications. Moreover, it explores the emerging trend of utilizing pineapple
leaf fiber, a sustainable and lightweight material, in structural applications, such as UAV construction. With its
exceptional mechanical properties and biodegradability, pineapple leaf fiber holds promise as a viable alternative to traditional materials, contributing to a more sustainable future. In conclusion, this review advocates for
a paradigm shift towards embracing agricultural plant waste as a valuable asset for economic prosperity and
environmental sustainability. It underscores the importance of continued research and technological advancements to unlock the full potential of agricultural waste in fostering a circular economy and driving sustainable
development globally.
Modelling of Multi-Bolted Systems at the Pretension Stage – Part 1: Mechanical Characteristics of the Contact between the Joined Elements
Archives of Metallurgy and Materials, Jun 21, 2024
The subject of the paper is the modelling of multi-bolted connections that are at the pretensioni... more The subject of the paper is the modelling of multi-bolted connections that are at the pretensioning stage. taking a systematic approach to the modelling issue, the connection was treated as a composite of four subsystems: a bolt set, a pair of joined elements and a contact layer between them. the first part of the paper describes experimental studies to determine the contact stiffness of a pair of elements separated from an exemplary asymmetric multi-bolted connection. the normal loading and unloading direction of the contact joint was considered. the tests were performed with the use of an iNstRoN 8850 servo-hydraulic testing machine equipped with an extensometer. a normal stiffness characteristic in the form of an exponential function was proposed for the tested contact joint. it will be applied in the second part of the paper, in which finite element modelling of the multi-bolted connection will be presented.
Materials, 2025
The paper presents the effect of the symmetric and asymmetric semi-metallic gasket core shape on ... more The paper presents the effect of the symmetric and asymmetric semi-metallic gasket core shape on the tightness level in bolted flange joints. Experimental tests, as well as numerical calculations based on the finite element method, revealed that the asymmetric gasket core provides a higher strain on the sealing graphite layer and leads to a more uniform distribution of strain on the particular ridges of the core. Furthermore, the leakage rate of the asymmetric gasket was reduced by approximately 60% compared to the symmetric gasket. It was also observed that the uniformity of pressure and strain distribution in a gasket with an asymmetric core occurs over about 80% of the gasket width. The leakage reduction effect in a flange joint sealed with a gasket with an asymmetric core was theoretically explained. As shown, the main leakage flows through the porous structure of the graphite layer, while the leakage path at the interface between the metal rough profile and the graphite layer is several orders of magnitude smaller.
Coatings, 2025
Among the biggest challenges in modern manufacturing techniques is deliberately shaping the surfa... more Among the biggest challenges in modern manufacturing techniques is deliberately shaping the surface layer of a part to suit the conditions in which it will be used. The degree of difficulty increases with the increase in the functional requirements of the items to be manufactured and with the complexity of the technology developed. Hybrid machining processes allow functional surfaces to be shaped by combining different machining operations into a single operation. The values of the amplitude and length parameters of the resulting surface geometrical texture are largely determined by the technological parameters of the combined machining operations. However, it is the tool guidance and kinematic-geometric conditions during the hybrid machining process that are responsible for the surface texture. This paper describes the results of an investigation into the influence of the milling tool guidance strategy during shaping milling and tooling guidance during burnishing of workpieces made of 42CrMo4 steel tempered to a hardness of 35 ± 2 HRC-a material commonly used in the construction of machine parts. It was shown that running the burnishing with two crossing passes oriented obliquely to the marks left by the cutter was the most favourable of the burnishing strategies tested.
WSEAS transactions on applied and theoretical mechanics, Jun 22, 2023
Advances in Science and Technology Research Journal, 2025
This paper presents the results of model tests related to the process of forming a pipeline arch ... more This paper presents the results of model tests related to the process of forming a pipeline arch by mechanical mandrel bending. The problems that occur during the pipeline manufacturing process and the methods and instrumentation used in forming the bent section of a pipeline, in particular the so-called mandrel bending, are presented. The main part of the paper consists of the results of model tests of stresses and deformations arising from the process of forming the arc of a mechanically bent pipeline using the proposed version of the mandrel with a torus-shaped forming part. These studies included an analysis of the effect of the pre-positioning of the mandrel on the values of deformations and stresses occurring in the cross-section of the bent pipe arch as a function of changes in the wall thickness and external diameter of the pipe and the bending radius. Based on the test results obtained, criteria were established enabling the selected pipe bending method to be used so that the resulting stresses and dimensions in the cross-sections of the bent pipe section are within the limits imposed by the normative recommendations. It was also shown that the criterion determining the efficiency of the bending process is the allowable recommended value of the ovalisation of the pipe cross-section.
Materials, 2025
Fiber-reinforced composites are widely utilized across various industries, including aerospace, a... more Fiber-reinforced composites are widely utilized across various industries, including aerospace, automotive, and marine, due to their outstanding mechanical properties and lightweight characteristics. Natural fibers, as promising reinforcements, have the potential to replace synthetic fibers in certain areas to meet the growing demand for environmental protection and sustainability. These biocomposites offer numerous benefits, including reduced carbon footprints, diminished reliance on non-renewable resources, and increased natural biodegradability. In addition, utilizing such eco-friendly materials is a critical strategy for balancing industry progress and environmental protection. Kenaf fiber, a superior bast fiber known for its excellent mechanical properties and high cellulose content, presents considerable advantages for enhancing the performance of biocomposites. This review explores the potential of kenaf fiber-reinforced biocomposites for marine applications, focusing on their fabrication and testing methods to evaluate their physicochemical and mechanical properties. This paper examines the chemical composition and mechanical properties of the kenaf fiber, investigates the excellent performance advantages of kenaf fiber-based biocomposites by hybridization manufacturing, and provides an overview of the status and challenges of applying such biocomposites in marine environments. Based on this review, it is evident that kenaf fiber-reinforced biocomposites have significant superiority for marine applications with the advancement of manufacturing techniques.
WSEAS Transactions on Applied and Theoretical Mechanics, 2025
The paper presents a piece of research carried out on the development of modelling and calculatio... more The paper presents a piece of research carried out on the development of modelling and calculation methods for multi-bolted connections. The influence of the modelling of the separated bolted joint on the value of the working load in the bolt was considered. A stiffness analysis of the bolted joint for selected linear and non-linear models was carried out. Guidelines for the selection of the modelling method for the analysis of working loads occurring in a bolted joint are discussed.
TTS Technika Transportu Szynowego, 2014
Applied Sciences, 2025
The design process is a complex task in which different goals and properties have to be achieved.... more The design process is a complex task in which different goals and properties have to be achieved. Nowadays, end-of-life issues are increasingly being considered in addition to typical design properties such as durability, appearance or quality. This article presents the product design process in relation to its recycling and mechanical properties. A plate connection in two design versions was chosen as the product: in the form of a multi-bolted connection and a multi-riveted connection. An analysis was conducted for several vari-ants of these connections. Recycling properties were considered using various measures calculated from the Recycling Product Model, a type of product model that includes its re-cycling properties. Selected mechanical properties were determined using the Finite Ele-ment Method. Removing one bolt from the connection resulted in a stiffness reduction of almost 11%, while removing two bolts from the connection resulted in a stiffness reduction of almost 26%. In contrast, the removal of one rivet from the connection led to a stiffness reduction of about 3%, while the removal of two rivets from the connection led to a stiff-ness reduction of less than 5%.
Lubricants, 2024
Due to the need to form a surface layer with specific operating properties, recent years have see... more Due to the need to form a surface layer with specific operating properties, recent years have seen an increased interest in surface strengthening treatment, which aims to create a surface layer that improves the durability of parts. With a view to the economics of the machining process, it is common to combine shaping milling, characterised by high volu-metric efficiency, with finishing burnishing, during which significant forces are applied. In the literature, one of the important limitations of such technological operations is the value of residual stresses, excessive values of which can lead to the flaking and falling off of surface fragments. In the present study, the authors put forward the research hypothesis that, in addition to stresses, the geometry of the machining roughness is also important and may contribute to faster tribological wear than stresses. It has been shown that what is important in hybrid machining is not so much the height of the resulting irregularities and the effectiveness of their levelling by burnishing, but the geometry of the irregularities. Af-ter milling, surfaces with small, regular irregularities with smooth peaks and shallow val-leys were found to be the best in tribological tests. Such roughness can be plastically lev-elled out during burnishing. On the basis of the experimental studies carried out, it was shown that a higher burnishing force does not always lead to higher wear resistance.
Advances in Science and Technology Research Journal, 2025
The presented paper proposes a some concept of an evacuation drone that could pick up the wounded... more The presented paper proposes a some concept of an evacuation drone that could pick up the wounded from the battlefield and transport them to their final destination for adequate medical care. The existing state of the art of drones and their equipment is described, as well as the possibility of using current technology to build a new drone. This paper presents a vision of the ‘future/ideal drone’ and the ‘technically/reasonably achievable drone today’, and consequently the levels of its development. The main rationale for choosing a drone configuration, including the basic characteristic sizes, is discussed. In view of the purpose of the drone, i.e. need to perform basic medical activities, current robots used
in remote surgery were analysed. Due to the fact that the final version of the drone is to take up the wounded without the participation of a third party, design aspects related to this are presented and examples of solutions are proposed.
Metals, 2024
This study investigates the application of Phased Array Corrosion Mapping (PACM) as a non-destruc... more This study investigates the application of Phased Array Corrosion Mapping (PACM) as a non-destructive testing (NDT) method for detecting and monitoring corrosion growth on hot stainless steel (SS) surfaces, specifically focusing on SS 304 and SS 316. Conducted across a temperature range of 30 ◦C to 250 ◦C, the research evaluates the effectiveness of PACM in high-temperature environments typical of the petrochemical industry. Experiments were conducted using specimens with machined slots and flat-bottom holes (FBHs) to simulate corrosion defects. The results demonstrate that PACM effectively detects and maps corrosion indicators, with color-coded C-scan data facilitating easy
interpretation. Temperature variations significantly influenced ultrasound signal characteristics, leading to observable changes in FBH indications, particularly at elevated temperatures. Increased ultrasound attenuation necessitated adjustments in decibel settings to maintain accuracy. SS 304
and SS 316 exhibited distinct responses to temperature changes, with SS 316 showing higher dB values and unique signal behaviors, including increased scattering and noise echoes at elevated temperatures. Detected depths for slots and FBHs correlated closely with designed depths, with
deviations generally less than 0.5 mm; however, some instances showed deviations exceeding 2 mm, underscoring the need for careful interpretation. At temperatures above 230 ◦C, the disbanding
of probe elements led to weak or absent signals, complicating data interpretation and requiring adjustments in testing protocols. This study highlights the feasibility and effectiveness of PACM for corrosion detection on hot SS surfaces, providing critical insights into material behavior under thermal conditions. Future research should include physical examination of samples using Scanning Electron Microscopy (SEM) to validate and enhance the reliability of the findings. The integration of non-contact NDT methods and optimization of calibration techniques are essential for improving PACM performance at elevated temperatures.
Materials, 2024
Natural composites are emerging as promising alternative materials for 3D printing in biomedical ... more Natural composites are emerging as promising alternative materials for 3D printing in biomedical applications due to their biocompatibility, sustainability, and unique mechanical properties. The use of natural composites offers several advantages, including reduced environmental impact, enhanced biodegradability, and improved tissue compatibility. These materials can be processed into filaments or resins suitable for various 3D printing techniques, such as fused deposition modeling (FDM). Natural composites also exhibit inherent antibacterial properties, making them particularly suitable for applications in tissue engineering, drug delivery systems, and biomedical implants. This review explores the potential of utilizing natural composites in additive manu-facturing for biomedical purposes, discussing the historical development of 3D printing tech-niques, the types of manufacturing methods, and the optimization of material compatibility, printability, and mechanical properties to fully utilize the potential of using natural fibers in 3D printing for biomedical applications.
WSEAS Transactions on Applied and Theoretical Mechanics, 2024
Finite element modeling of multi-bolted foundation connections applied in the case of seating of ... more Finite element modeling of multi-bolted foundation connections applied in the case of seating of heavy machines or devices is reported. Connections performed by means of 3 different types of chocks were investigated. Characteristics of stiffness for the assumed models of multi-bolted foundation connections at the assembling phase were outlined and discussed. Conclusions of great relevance to engineering design were presented.
Materials, 2024
This paper presents a method for modelling the permeability of fluid at the interface formed betw... more This paper presents a method for modelling the permeability of fluid at the interface formed between flat parallel plates and the sharp-edged ridges of a metal gasket. This work was divided into three stages. In the first stage, numerical calculations simulating the deformation (compression of the gasket) were performed. The calculations were carried out using thermomechanical static analysis with commercial software. The purpose of these calculations was to determine the contact area of the gasket ridges with the plates, the deformation of the gasket ridges, and the reaction force resulting from the degree of compression of the gasket. In the second part of this work, analytical calculations were performed to estimate the tightness level. The analytical model proposed in this paper was based on Darcy's equation, simulating fluid flow through a ring-shaped porous layer. The analytical model also took into account the shape of the roughness profile of the sealed surfaces. A mathematical Ausloos-Berman function based on fractal theory was used to represent it. In the last part of this work, experimental tests were carried out to determine the actual fluid permeability and thus verify the numerical and analytical calculations.
Journal of Composites Science, 2024
Highly efficient fiber-reinforced composites find extensive application in diverse industries. Ye... more Highly efficient fiber-reinforced composites find extensive application in diverse industries. Yet, conventional fiber-reinforced composites have significant environmental impacts during both manufacturing and disposal. Environmentally friendly fiber-reinforced composites have garnered significant attention within the framework of sustainable development. Utilizing natural fibers in place of synthetic fibers and progressively decreasing the use of synthetic fibers are the main approaches to achieving a balance between economic progress and environmental quality. At-tention is increasingly being drawn to natural fiber-reinforced biocomposites that exhibit out-standing environmental performance, exceptional physical and mechanical capabilities, and bi-ological features. The lightweight and high-strength characteristics of these biocomposites enable them to significantly decrease the weight of structures, making them increasingly popular in many industries. The objective of this review is to evaluate the effectiveness of hybrid fiber-reinforced biocomposites in marine applications, specifically examining their mechanical characteristics, resistance to seawater, and ability to absorb moisture, all while advocating for sustainable ma-terial methodologies. To achieve this objective, the paper delineates the distinction between synthetic and natural fibers, examines the benefits of hybrid fiber-reinforced biocomposite ma-terials, and addresses the obstacles and effective approaches in their production and application in seawater. Considering the review analysis, it can be inferred that the use of fiber-reinforced bi-ocomposites in maritime applications shows significant potential and has abundant untapped growth prospects in the future years.
Applied Sciences, 2024
Modern technology allows ductile cast iron parts to be efficiently machined while ensuring a rela... more Modern technology allows ductile cast iron parts to be efficiently machined while ensuring a rela-tively long tool life. One of the basic indices describing the susceptibility of ductile cast irons to change in volume, shape, and dimensions under machining conditions is their machinability. Machinability can be expressed directly in terms of the values of basic quantities such as periodic cutting speed and roughness. At the same time, machinability is a relative quantity evaluated alternatively. This means that the machinability of ductile cast iron can be good, allowing high cutting speeds to be achieved, but it can also be poor, expressed in terms of poor surface quality. In the experimental research carried out, an attempt was made to determine the limit values of the cutting speed, beyond which one should not exceed, in order to increase the efficiency of the machining process. The surface roughness, unlike the periodic cutting speed, is a quantity defined in the product design docu-mentation, so its limits must be observed. In addition to the usual indices of surface geometric texture, the research analysed alternative indices for determining the condition of surface geometric texture and the influence of periodic cutting speed on their values. In the conclusions, valuable recommendations are given for designers and technologists on the purpose and functionality of product surfaces and how to define them. Methods of specifying tribological characteristics, hy-drophobic or hydrophilic properties, as well as the ability to retain fluids and maintain protective coatings of ductile cast iron parts after machining are described, for which relative values, depending on the machining parameters used, can vary from about 10 to even 30%.
Modelling, 2024
Finite element modelling of multi-bolted foundation connections used for the foundation of heavy ... more Finite element modelling of multi-bolted foundation connections used for the foundation of
heavy machinery or equipment is presented. Connections made using different types of shims, with
particular emphasis on polymer–steel shims, are investigated. The stiffness characteristics for the
adopted models of multi-bolted foundation connections at the installation stage are described and
compared. It is shown that the use of polymer–steel shims can result in a significant improvement in
the stiffness of a multi-bolted foundation connection compared to a connection with a polymer shim,
and in achieving a multi-bolted foundation connection with a stiffness similar to that of a connection
with a steel shim (at a sufficiently low polymer layer thickness).
Precision Engineering, 2024
The paper presents the procedures developed to correctly assess the geometric condition of large ... more The paper presents the procedures developed to correctly assess the geometric condition of large crankshafts using a novel measurement system equipped with a specially designed prism support system with computer monitoring of support reaction forces. These procedures were developed for three variants of measurement execution corresponding to conditions: non-referenced (fixing of the shaft to be measured with the outer extremes of the faces in the spherical prisms and supporting the shaft in the central part with a set of supports referred to as ‘elastic’), referenced (fixing of the shaft to be measured by the outer extremes of the main journals in prisms and support of the crankshaft in the central part, as in the case of the previous variant, by a set of supports referred to as ‘elastic’) and realised in conditions similar to the traditional ones (fixing and support of the crankshaft by a set of prism supports maintaining a constant height position). Considering the utilitarian potential of the developed procedures, exemplary applications of their practical use in the measurement of large crankshafts are presented.
Advances in Science and Technology Research Journal, 2024
The escalating global population and subsequent demand for agricultural products have led to a su... more The escalating global population and subsequent demand for agricultural products have led to a surge in agricultural waste generation, posing significant disposal challenges. Conventional disposal methods such as burning
and dumping not only harm the environment but also jeopardize human health and safety. Recognizing the urgent need for sustainable waste management, researchers have increasingly focused on repurposing agricultural
plant waste as a valuable resource. This paper presents a comprehensive review of the potential of agricultural
plant waste in wealth creation and sustainable development. It highlights the detrimental impacts of current
disposal methods and emphasizes the necessity for alternative approaches. By analyzing the physical, mechanical, and chemical properties of plant fibers, particularly cellulose, hemicellulose, and lignin, this review underscores their suitability for diverse applications. Moreover, it explores the emerging trend of utilizing pineapple
leaf fiber, a sustainable and lightweight material, in structural applications, such as UAV construction. With its
exceptional mechanical properties and biodegradability, pineapple leaf fiber holds promise as a viable alternative to traditional materials, contributing to a more sustainable future. In conclusion, this review advocates for
a paradigm shift towards embracing agricultural plant waste as a valuable asset for economic prosperity and
environmental sustainability. It underscores the importance of continued research and technological advancements to unlock the full potential of agricultural waste in fostering a circular economy and driving sustainable
development globally.
Modelling of Multi-Bolted Systems at the Pretension Stage – Part 1: Mechanical Characteristics of the Contact between the Joined Elements
Archives of Metallurgy and Materials, Jun 21, 2024
The subject of the paper is the modelling of multi-bolted connections that are at the pretensioni... more The subject of the paper is the modelling of multi-bolted connections that are at the pretensioning stage. taking a systematic approach to the modelling issue, the connection was treated as a composite of four subsystems: a bolt set, a pair of joined elements and a contact layer between them. the first part of the paper describes experimental studies to determine the contact stiffness of a pair of elements separated from an exemplary asymmetric multi-bolted connection. the normal loading and unloading direction of the contact joint was considered. the tests were performed with the use of an iNstRoN 8850 servo-hydraulic testing machine equipped with an extensometer. a normal stiffness characteristic in the form of an exponential function was proposed for the tested contact joint. it will be applied in the second part of the paper, in which finite element modelling of the multi-bolted connection will be presented.
Proc. of the XXXI International Conference CAD in Machinery Design Implementation and Educational Issues (Supraśl, Poland, 26-28 X 2023), 2024
The paper deals with the modelling of multi-bolted connections under preload conditions in a syst... more The paper deals with the modelling of multi-bolted connections under preload conditions in a systemic approach. A modelling procedure based on the finite element method is presented. According to it, the connection was treated as a combination of four subsystems: a bolt-nut set, a pair of joined components and a contact layer between them. The contact layer model used allows the actual mechanical properties of the contact joint to be taken into account. The application of the method is illustrated using the example of an asymmetric connection. First, its solid model was built, followed by a discrete model in which the bolt-nut set was replaced by a hybrid model with a non-deformable bolt head and nut and a deformable bolt shank. Finally, selected results of connection calculations are also provided. The utilitarian relevance of a systemic approach to modelling multi-bolted connections and the opportunities it delivers for connection assessment is presented.
Fundamentals of machine design. Selected problems, 2020
The paper is related to modeling of multi-bolted connections treated as a system in the assembly ... more The paper is related to modeling of multi-bolted connections treated as a system in the assembly state. The model of the connection with various models of the contact layer between joined elements is presented. The system has been pretensioned in accordance with the specified tightening sequence of bolts and in several tightening cycles. Sample calculations were made for the selected asymmetrical flange connection. As a result of these calculations, the preload distributions in one of the bolts are shown.
AIP Conference Proceedings, 2019
The paper is related to modeling of multi-bolted joints treated as a system. The model of the joi... more The paper is related to modeling of multi-bolted joints treated as a system. The model of the joint with various substitute models of bolts is presented. The system was pre-tensioned and externally loaded with normal forces. Calculations were made for an exemplary asymmetric joint. As a result of these calculations, distributions of operational forces in the bolts are shown.
IEEE Conferences, Proc. of the 2018 International Interdisciplinary PhD Workshop (IIPhDW 2018) (Świnoujście, Poland, 9-12 May 2018), Szczecin, ZUT w Szczecinie 2018, 2018
Modelling and calculations of a bolted flange connection located under elevated temperature condi... more Modelling and calculations of a bolted flange connection located under elevated temperature conditions are presented. Analysis of forces acting on the bolt and the joined elements on the basis of analytical formulas and using the finite element method (FEM) is performed. In the case of theoretical calculations the recommendations given in books on the fundamentals of machine design are applied. For a case of numerical calculations a simplified model of the bolt is used. The obtained results of calculations are checked in terms of fulfilment of the adopted strength criterion associated with acceptable thermal stress in the bolt. Selected results of simulation studies of the connection FEM-model in the form of temperature distribution in the model are shown. On the basis of the comparison of the theoretical and numerical analyses results, the usefulness of the simplified bolt model for calculations of forces in the bolts in flange connections under elevated temperature conditions is determined.
Modelling normal properties of a nonlinear contact in multi-bolted systems
Proc. of the 22nd International Scientific Conference “MECHANIKA 2017“ (Birštonas, Lithuania, 19 May 2017), Kaunas, Kaunas University of Technology 2017, 114-117.
The paper deals with modelling and calculations of a contact layer between elements joined in a m... more The paper deals with modelling and calculations of a contact layer between elements joined in a multi-bolted joint for the assembly condition. The physical mod-el of the multi-bolted joint is based on a system consisting of a flexible flange element that is joined with a flexible support by means of the rigid body bolt model. The contact layer between joined elements is described as the nonlinear Winkler model. The contact joint model considering an experimental normal elastic characteristic is presented. Examples of normal contact pressure distributions are contained.
Impact of nonlinearity on bolt forces in multi-bolted systems: a case of the assembly state
Proc. of the 22nd International Scientific Conference “MECHANIKA 2017“ (Birštonas, Lithuania, 19 May 2017), Kaunas, Kaunas University of Technology 2017, 110-113.
The paper deals with modelling and calculations of asymmetrical multi-bolted joints treated as a ... more The paper deals with modelling and calculations of asymmetrical multi-bolted joints treated as a system composed of four subsystems at the assembly stage. These subsystems are: a couple of joined elements, a contact layer between the elements, and a set of bolts. The contact layer is formed as the Winkler model, and the set of bolts are modeled using simplified beam models. The truth of the theorem has been tested, according to which nonlinearity of the contact layer has a negligible impact on the final values of the bolt forces in the case of sequential tightening of the multi-bolted joint.
Aktualne problem naukowo-techniczne budownictwa
The theme of the paper is to determine effective methods of contemporary building structures vibr... more The theme of the paper is to determine effective methods of contemporary building structures vibration analysis. The results of application of the experimental modal analysis in order to assign the modal parameters of the model, mapping a typical column-beam-plate structure founded on a rigid base, is presented. The study is carried out in the form of a impulse test. Based on the test results analysis modal parameters of the model as a set of natural frequencies and corresponding mode shapes as well as modal attenuation coefficients are estimated. The model is validated using the MAC (Modal Assurance Criterion).
Palenica P., Powałka B., Grzejda R.: Assessment of modal parameters of a building structure model, Springer Proceedings in Mathematics & Statistics, vol. 181, 319-325., Sep 2016
This paper relates to the field of vibrations of contemporary building structures. The aim of thi... more This paper relates to the field of vibrations of contemporary building structures. The aim of this study is to develop methods to estimate the safety of use of buildings subjected to dynamic loads. Calculations are carried out based on selected computational models of the column-beam-plate system used at the design stage of monolithic building structures. For modeling, the finite element method (FEM) is used. The results of calculations are compared with laboratory tests of the special model mapping of a building structure.
Grzejda R.: Comparative analysis of selected methods for seating of machines using foundation bolted joints, Proc. of the XXV International Conference on Theory of Machines and Mechatronic Systems (Nowy Sącz – Rytro, Poland, 18-21 IX 2016), Sep 18, 2016
Finite element modelling of foundation bolted joints applied in the case of seating of heavy mach... more Finite element modelling of foundation bolted joints applied in the case of seating of heavy machines or devices is presented. The joints made with the use of three different types of chocks are examined. Stiffness characteristics for the adopted models of the foundation bolted joint at the assembly stage are described and compared. Conclusions of paramount importance to the engineering practice are created.
Proc. of the 15th International Scientific Conference “Engineering for Rural Development 2016“ (Jelgava, Latvia, 25-27 May 2016), Jelgava, Latvia University of Agriculture 2016, 336-341.
The report deals with modelling and calculations of asymmetrical multi-bolted connections at the ... more The report deals with modelling and calculations of asymmetrical multi-bolted connections at the operational stage. The physical model of the joint is based on a flexible flange element that is connected with a rigid support by means of the spider bolt models. Between the joined elements the nonlinear Winkler model of a contact layer is taken into consideration. A computational model of the system is proposed, which makes it possible to analyze any preloaded multi-bolted connection subjected to an eccentric normal load. The sample results obtained from the calculations are presented.
Proc. of the 15th International Scientific Conference “Engineering for Rural Development 2016“ (Jelgava, Latvia, 25-27 May 2016), Jelgava, Latvia University of Agriculture 2016, 329-335.
The article deals with modelling and calculations of asymmetrical multi-bolted connections at the... more The article deals with modelling and calculations of asymmetrical multi-bolted connections at the assembly stage. The physical model of the joint is based on a flexible flange element that is connected with a rigid support by means of the spider bolt models. Between the joined elements the nonlinear Winkler model of a contact layer is taken into consideration. A computational model of the system is proposed, which makes it possible to analyze how the tightening sequence affects the distribution of preload both during the multi-bolted connection assembly and after it has been completed. The sample results obtained from the calculations are presented.
Advances in Mechanics: Theoretical, Computational and Interdisciplinary Issues, Proc. of the 3rd Polish Congress of Mechanics (PCM) and 21st International Conference on Computer Methods in Mechanics (CMM) (Gdansk, Poland, 8-11 September 2015), Leiden, CRC Press/Balkema 2016, 213-216.
Multi-bolted connections are systems of many bodies being in a contact. These systems are compose... more Multi-bolted connections are systems of many bodies being in a contact. These systems are composed of: fasteners, joined elements and contact joints between them. There are known methods for modelling and calculation of parts of typical multi-bolted connections, which are geometrically symmetrical or symmetrically loaded. A novelty is a treatment of the multi-bolted connection as a system consisting of components, which can be considered, modelled and calculateted as separate subsystems using methods adequate to their properties. The aim of this paper is to present the concept of a new modelling method of multi-bolted connections dealing with as multi-bolted systems. The model assumptions and modelling bases of separate subsystems of a physical model of the multi-bolted connection are given. The outcome of actions described in this paper is establishment of the equilibrium equations, which can be applied for any condition of the multi-bolted system. Calculations results of a selected multi-bolted connection are presented.