Szymon Duda - Academia.edu (original) (raw)

Papers by Szymon Duda

Composite Structures, Jun 1, 2023

Composite Structures, Aug 1, 2022

International Journal of Fracture, Jul 9, 2021

Fiber metal laminates (FML) are hybrid materials consisting of metal and composite layers. They h... more Fiber metal laminates (FML) are hybrid materials consisting of metal and composite layers. They have great mechanical and fatigue properties. However, interface between metal and composite layers can be critical for their final properties. In this paper, process of determination of some fracture parameters of this interface in unusual FML material is described. Experimental tests following ASTM norm were conducted using Double Cantilever Beam (DCB). However, due to asymmetry, fracture energy cannot be obtained directly from the force-displacement curve. Finite element method simulations were carried out using cohesive elements and cohesive surfaces approach. The cohesive behavior of interface layers were modelled using traction separation law. Key properties of this law were obtained-maximal traction and fracture energy. In this particular case cohesive approach was better in reflecting experimental results. Determined values can be used in later research tasks (like modelling big structures containing this material) as material properties. The presented approach can be used successfully to obtain fracture energy in cases of materials for which standard approach is insufficient.

Materials, Apr 17, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Structural integrity, 2022

Engineering Failure Analysis, Mar 1, 2022

Materials

Polyurethane (PU) has been used in a variety of industries during the past few years due to its e... more Polyurethane (PU) has been used in a variety of industries during the past few years due to its exceptional qualities, including strong mechanical strength, good abrasion resistance, toughness, low-temperature flexibility, etc. More specifically, PU is easily “tailored” to satisfy particular requirements. There is a lot of potential for its use in broader applications due to this structure–property link. Ordinary polyurethane items cannot satisfy people’s increased demands for comfort, quality, and novelty as living standards rise. The development of functional polyurethane has recently received tremendous commercial and academic attention as a result. In this study, the rheological behavior of a polyurethane elastomer of the PUR (rigid polyurethane) type was examined. The study’s specific goal was to examine stress relaxation for various bands of specified strains. We also suggested the use of a modified Kelvin–Voigt model to describe the stress relaxation process from the perspect...

Archives of Civil and Mechanical Engineering

In this paper, pultruded GFRP bars are investigated to determine their fracture properties. The d... more In this paper, pultruded GFRP bars are investigated to determine their fracture properties. The double cantilever beam test (DCB) is used to assess fracture behavior under mode I loading conditions. However, due to the presence of the R-curve effect (variable fracture energy dependent on the length of the crack), it is necessary to introduce a nonstandard approach to determine fracture properties. The mixed experimental–numerical approach is proposed to deal with this issue. Numerical simulations were carried out in Simulia Abaqus, and with Python scripting it was possible to generate models and obtain R-curve for the material. The numerical model built based on the experimental results has very good agreement with it (force–displacement and delamination length–time characteristics) which allows the use of the mentioned model in the analysis of more complex structures. Acoustic emission analysis was introduced as an auxiliary technique. The delamination obtained from both the numeri...

International Journal of Fracture, 2021

Fiber metal laminates (FML) are hybrid materials consisting of metal and composite layers. They h... more Fiber metal laminates (FML) are hybrid materials consisting of metal and composite layers. They have great mechanical and fatigue properties. However, interface between metal and composite layers can be critical for their final properties. In this paper, process of determination of some fracture parameters of this interface in unusual FML material is described. Experimental tests following ASTM norm were conducted using Double Cantilever Beam (DCB). However, due to asymmetry, fracture energy cannot be obtained directly from the force–displacement curve. Finite element method simulations were carried out using cohesive elements and cohesive surfaces approach. The cohesive behavior of interface layers were modelled using traction separation law. Key properties of this law were obtained—maximal traction and fracture energy. In this particular case cohesive approach was better in reflecting experimental results. Determined values can be used in later research tasks (like modelling big s...

Archives of Computational Methods in Engineering, Sep 6, 2022

Fibre metal laminates (FML) are layered materials consisting of both metal and reinforced composi... more Fibre metal laminates (FML) are layered materials consisting of both metal and reinforced composite layers. Due to numerous possibilities of configuration, constituent materials, etc., designing and testing such materials can be time-and costconsuming. In addition to that, some parameters cannot be obtained directly from the experiment campaign. These problems are often overcome by using numerical simulation. In this article, the authors reviewed different approaches to finite element analysis of fibre metal laminates based on published articles and their own experiences. Many aspects of numerical modelling of FMLs can be similar to approaches used for classic laminates. However, in the case of fibre metal laminates, the interface between the metal and the composite layer is very relevant both in experimental and numerical regard. Approaches to modelling this interface have been widely discussed. Numerical simulations of FMLs are often complementary to experimental campaigns, so an experimental background is presented. Then, the software used in numerical analysis is discussed. In the next two chapters, both static and fatigue failure modelling are discussed including several key aspects like dimensionality of the model, approaches to the material model of constituents and holistic view of the material, level of homogenization, type of used finite elements, use of symmetry, and more. The static failure criteria used for both fibres and matrix are discussed along with different damage models for metal layers. In the chapter dedicated to adhesive interface composite-metal, different modelling strategies are discussed including cohesive element, cohesive surfaces, contact with damage formulation and usage of eXtended Finite Element Method. Also, different ways to assess the failure of this layer are described with particular attention to the Cohesive Zone Model with defined Traction-Separation Law. Furthermore, issues related to mixed-mode loading are presented. In the next chapter other aspects of numerical modelling are described like mesh sensitivity, friction, boundary conditions, steering, user-defined materials, and validation. The authors in this article try to evaluate the quality of the different approaches described based on literature review and own research.

Materials

This paper presents the results of a study of polyurethane rigid (PUR) elastomers in terms of the... more This paper presents the results of a study of polyurethane rigid (PUR) elastomers in terms of the constitutive law identification, and analyses the effect of polyurethane elastomers’ hardness on fatigue properties. The research objects were PUR materials based on 4,4′-diphenylmethane diisocyanate (MDI) with the hardness of 80 ShA and 90 ShA, typically used in various industrial applications. Based on the performed experimental campaign under static and cyclic loading, the constitutive model proposed by Ogden is most appropriate. In addition, a hybrid numerical–experimental analysis (using FEM-DIC) of diabolo specimens’ behaviour is carried out in fatigue tests. Based on the performed fatigue test, it is worth noting that the energy approach describes the fatigue process synonymously compared to the displacement or strain approach. Finally, simple fatigue characteristics were analyzed and statistically validated for both PUR material configurations.

International Journal of Fatigue

Polymers

Fire resistance is a major issue concerning composite materials for safe operation in many indust... more Fire resistance is a major issue concerning composite materials for safe operation in many industrial sectors. The design process needs to meet safety requirements for buildings and vehicles, where the use of composites has increased. There are several solutions to increasing the flame resistance of polymeric materials, based on either chemical modification or physical additions to the material’s composition. Generally, the used flame retardants affect mechanical properties either in a positive or negative way. The presented research shows the influence of the mixed-mode behavior of epoxy resin. Fracture toughness tests on epoxy resin samples were carried out, to investigate the changes resulting from different inorganic filler contents of aluminum trihydroxide (ATH). Three-point bending and asymmetric four-point bending tests, with different loading modes, were performed, to check the fracture behavior in a complex state of loading. The results showed that the fracture toughness of...

This paper presents the experimental results of composite rebars based on GFRP manufactured by a ... more This paper presents the experimental results of composite rebars based on GFRP manufactured by a pultrusion system. The bending and radial compression strength of rods was determined. The elastic modulus of GFRP rebars is significantly lower than for steel rebars, while the static flexural properties are higher. The microstructure of the selected rebars was studied and discussed in light of the obtained results—failure processes such as the delamination and fibers fracture can be observed. The bending fatigue test was performed under a constant load amplitude sinusoidal waveform. All rebars were subjected to fatigue tests under the R = 0.1 condition. As a result, the S-N curve was obtained, and basic fatigue characteristics were determined. The fatigue mechanism of bar failure under bending was further analyzed using SEM microscopy. It is worth noting that the failure and fracture mechanism plays a crucial role as a material quality indicator in the manufacturing process. The main m...

The problem with composite rebars in the civil engineering industry is often described as the mat... more The problem with composite rebars in the civil engineering industry is often described as the material’s brittleness while overloaded. To overcome this drawback, researchers pay attention to the pseudo-ductility effect. The paper presents four-point bending tests of pure unidirectional (UD) rods with additional composite layers obtained by filament winding and hand braiding techniques. Two types of core materials, glass FRP (fibre reinforced polymer) and carbon FRP, were used. Regarding the overwrapping material, the filament winding technique utilized carbon and glass roving reinforcement in the epoxy matrix, while in the case of hand braiding, the carbon fibre sleeve was applied with the epoxy matrix. Microstructural analysis using scanning electron microscopy (SEM) and computed tomography (CT) was performed to reveal the structural differences between the two proposed methods. Mechanical test results showed good material behaviour exhibiting the pseudo-ductility effect after the ...

Composite Structures, Jun 1, 2023

Composite Structures, Aug 1, 2022

International Journal of Fracture, Jul 9, 2021

Fiber metal laminates (FML) are hybrid materials consisting of metal and composite layers. They h... more Fiber metal laminates (FML) are hybrid materials consisting of metal and composite layers. They have great mechanical and fatigue properties. However, interface between metal and composite layers can be critical for their final properties. In this paper, process of determination of some fracture parameters of this interface in unusual FML material is described. Experimental tests following ASTM norm were conducted using Double Cantilever Beam (DCB). However, due to asymmetry, fracture energy cannot be obtained directly from the force-displacement curve. Finite element method simulations were carried out using cohesive elements and cohesive surfaces approach. The cohesive behavior of interface layers were modelled using traction separation law. Key properties of this law were obtained-maximal traction and fracture energy. In this particular case cohesive approach was better in reflecting experimental results. Determined values can be used in later research tasks (like modelling big structures containing this material) as material properties. The presented approach can be used successfully to obtain fracture energy in cases of materials for which standard approach is insufficient.

Materials, Apr 17, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Structural integrity, 2022

Engineering Failure Analysis, Mar 1, 2022

Materials

Polyurethane (PU) has been used in a variety of industries during the past few years due to its e... more Polyurethane (PU) has been used in a variety of industries during the past few years due to its exceptional qualities, including strong mechanical strength, good abrasion resistance, toughness, low-temperature flexibility, etc. More specifically, PU is easily “tailored” to satisfy particular requirements. There is a lot of potential for its use in broader applications due to this structure–property link. Ordinary polyurethane items cannot satisfy people’s increased demands for comfort, quality, and novelty as living standards rise. The development of functional polyurethane has recently received tremendous commercial and academic attention as a result. In this study, the rheological behavior of a polyurethane elastomer of the PUR (rigid polyurethane) type was examined. The study’s specific goal was to examine stress relaxation for various bands of specified strains. We also suggested the use of a modified Kelvin–Voigt model to describe the stress relaxation process from the perspect...

Archives of Civil and Mechanical Engineering

In this paper, pultruded GFRP bars are investigated to determine their fracture properties. The d... more In this paper, pultruded GFRP bars are investigated to determine their fracture properties. The double cantilever beam test (DCB) is used to assess fracture behavior under mode I loading conditions. However, due to the presence of the R-curve effect (variable fracture energy dependent on the length of the crack), it is necessary to introduce a nonstandard approach to determine fracture properties. The mixed experimental–numerical approach is proposed to deal with this issue. Numerical simulations were carried out in Simulia Abaqus, and with Python scripting it was possible to generate models and obtain R-curve for the material. The numerical model built based on the experimental results has very good agreement with it (force–displacement and delamination length–time characteristics) which allows the use of the mentioned model in the analysis of more complex structures. Acoustic emission analysis was introduced as an auxiliary technique. The delamination obtained from both the numeri...

International Journal of Fracture, 2021

Fiber metal laminates (FML) are hybrid materials consisting of metal and composite layers. They h... more Fiber metal laminates (FML) are hybrid materials consisting of metal and composite layers. They have great mechanical and fatigue properties. However, interface between metal and composite layers can be critical for their final properties. In this paper, process of determination of some fracture parameters of this interface in unusual FML material is described. Experimental tests following ASTM norm were conducted using Double Cantilever Beam (DCB). However, due to asymmetry, fracture energy cannot be obtained directly from the force–displacement curve. Finite element method simulations were carried out using cohesive elements and cohesive surfaces approach. The cohesive behavior of interface layers were modelled using traction separation law. Key properties of this law were obtained—maximal traction and fracture energy. In this particular case cohesive approach was better in reflecting experimental results. Determined values can be used in later research tasks (like modelling big s...

Archives of Computational Methods in Engineering, Sep 6, 2022

Fibre metal laminates (FML) are layered materials consisting of both metal and reinforced composi... more Fibre metal laminates (FML) are layered materials consisting of both metal and reinforced composite layers. Due to numerous possibilities of configuration, constituent materials, etc., designing and testing such materials can be time-and costconsuming. In addition to that, some parameters cannot be obtained directly from the experiment campaign. These problems are often overcome by using numerical simulation. In this article, the authors reviewed different approaches to finite element analysis of fibre metal laminates based on published articles and their own experiences. Many aspects of numerical modelling of FMLs can be similar to approaches used for classic laminates. However, in the case of fibre metal laminates, the interface between the metal and the composite layer is very relevant both in experimental and numerical regard. Approaches to modelling this interface have been widely discussed. Numerical simulations of FMLs are often complementary to experimental campaigns, so an experimental background is presented. Then, the software used in numerical analysis is discussed. In the next two chapters, both static and fatigue failure modelling are discussed including several key aspects like dimensionality of the model, approaches to the material model of constituents and holistic view of the material, level of homogenization, type of used finite elements, use of symmetry, and more. The static failure criteria used for both fibres and matrix are discussed along with different damage models for metal layers. In the chapter dedicated to adhesive interface composite-metal, different modelling strategies are discussed including cohesive element, cohesive surfaces, contact with damage formulation and usage of eXtended Finite Element Method. Also, different ways to assess the failure of this layer are described with particular attention to the Cohesive Zone Model with defined Traction-Separation Law. Furthermore, issues related to mixed-mode loading are presented. In the next chapter other aspects of numerical modelling are described like mesh sensitivity, friction, boundary conditions, steering, user-defined materials, and validation. The authors in this article try to evaluate the quality of the different approaches described based on literature review and own research.

Materials

This paper presents the results of a study of polyurethane rigid (PUR) elastomers in terms of the... more This paper presents the results of a study of polyurethane rigid (PUR) elastomers in terms of the constitutive law identification, and analyses the effect of polyurethane elastomers’ hardness on fatigue properties. The research objects were PUR materials based on 4,4′-diphenylmethane diisocyanate (MDI) with the hardness of 80 ShA and 90 ShA, typically used in various industrial applications. Based on the performed experimental campaign under static and cyclic loading, the constitutive model proposed by Ogden is most appropriate. In addition, a hybrid numerical–experimental analysis (using FEM-DIC) of diabolo specimens’ behaviour is carried out in fatigue tests. Based on the performed fatigue test, it is worth noting that the energy approach describes the fatigue process synonymously compared to the displacement or strain approach. Finally, simple fatigue characteristics were analyzed and statistically validated for both PUR material configurations.

International Journal of Fatigue

Polymers

Fire resistance is a major issue concerning composite materials for safe operation in many indust... more Fire resistance is a major issue concerning composite materials for safe operation in many industrial sectors. The design process needs to meet safety requirements for buildings and vehicles, where the use of composites has increased. There are several solutions to increasing the flame resistance of polymeric materials, based on either chemical modification or physical additions to the material’s composition. Generally, the used flame retardants affect mechanical properties either in a positive or negative way. The presented research shows the influence of the mixed-mode behavior of epoxy resin. Fracture toughness tests on epoxy resin samples were carried out, to investigate the changes resulting from different inorganic filler contents of aluminum trihydroxide (ATH). Three-point bending and asymmetric four-point bending tests, with different loading modes, were performed, to check the fracture behavior in a complex state of loading. The results showed that the fracture toughness of...

This paper presents the experimental results of composite rebars based on GFRP manufactured by a ... more This paper presents the experimental results of composite rebars based on GFRP manufactured by a pultrusion system. The bending and radial compression strength of rods was determined. The elastic modulus of GFRP rebars is significantly lower than for steel rebars, while the static flexural properties are higher. The microstructure of the selected rebars was studied and discussed in light of the obtained results—failure processes such as the delamination and fibers fracture can be observed. The bending fatigue test was performed under a constant load amplitude sinusoidal waveform. All rebars were subjected to fatigue tests under the R = 0.1 condition. As a result, the S-N curve was obtained, and basic fatigue characteristics were determined. The fatigue mechanism of bar failure under bending was further analyzed using SEM microscopy. It is worth noting that the failure and fracture mechanism plays a crucial role as a material quality indicator in the manufacturing process. The main m...

The problem with composite rebars in the civil engineering industry is often described as the mat... more The problem with composite rebars in the civil engineering industry is often described as the material’s brittleness while overloaded. To overcome this drawback, researchers pay attention to the pseudo-ductility effect. The paper presents four-point bending tests of pure unidirectional (UD) rods with additional composite layers obtained by filament winding and hand braiding techniques. Two types of core materials, glass FRP (fibre reinforced polymer) and carbon FRP, were used. Regarding the overwrapping material, the filament winding technique utilized carbon and glass roving reinforcement in the epoxy matrix, while in the case of hand braiding, the carbon fibre sleeve was applied with the epoxy matrix. Microstructural analysis using scanning electron microscopy (SEM) and computed tomography (CT) was performed to reveal the structural differences between the two proposed methods. Mechanical test results showed good material behaviour exhibiting the pseudo-ductility effect after the ...