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Detta examensarbete vid Konstfack inom Inredningsarkitektur och Möbeldesign har kommit att handla om en vilja att lära sig något nytt och utmanas inom det en tidigare inte gjort. Inom arbetet har det kommit att bli en undersökning av ett Perstorpsbord från 1960-talet. Det har varit en källa till inspiration och visat på lärdomar inom möbelkonstruktion och möbelformgivning. Projektets tyngd ligger i att förstå och se samband mellan de två aspekterna. Med detta som grund har en transformation skett där Perstorpsbordet har kommit att bli ett nytt, med förändringar inom form, material och konstruktion. Avsikten har varit att gestalta det nya bordet kallat NAVET, för en ungdom som ofta flyttar emellan boenden. Med det i åtanke så har behov av bordet blivit fastställda som sedan kommit att bli en del av utformningen. Jag jobbar med Perstorpsbordets befintliga funktioner samtidigt som det ska placeras i samtiden och därmed utvecklas. Därav ändras bordets form, material och kulör, samtidigt som jag behåller de aspekter med Perstorpsbordet som utifrån mina undersökningar ansågs vara fungerande hos bordet ännu idag. Det var viktigt för mig att gå igenom en gestaltningsprocess av en möbel från start till slut. Från ett undersökande med nyfikenhet och öppna ögon, så var syftet att ta det vidare igenom en process av arbete som skisser, anteckningar, mock-up, prototyper och samtal med mera. För att leda fram till att själv stå i verkstaden och försöka förverkliga denna idé av ett bord i full skala. Mitt mål är att personligen utveckla mer kunskap om såväl en möbel, som dess relation till fältet samt hur jag själv jobbar. Jag upptäckte en för mig ny förundran inför möbler tack vare denna djupdykning och en förståelse för det arbete som ligger bakom. Jag anser därför att detta projekt har gett mig möjligheten att bli bättre som inredningsarkitekt och möbeldesigner., This thesis project at Konstfack in Interior Architecture and Furniture Design has centered on a desire to learn something new and be challenged in areas I have not previously explored. During this work, it has become an investigation of a Perstorp table from the 1960s. It has been a source of inspiration, providing insights into furniture construction and design. The project’s core lies in understanding and seeing the connections between these two aspects. Using this as a foundation, a transformation has taken place where the Perstorp table has become a new piece, with changes in form, material, and construction. The intention has been to design the new table, called NAVET (The Hub), for a young person who frequently moves between homes. With this in mind, the needs of the table were identified and subsequently incorporated into the design. I am working with the existing functions of the Perstorp table while also aiming to place it in a contemporary context and thus develop it further. Therefore, the table’s shape, material, and color have been changed, while retaining the aspects of the Perstorp table that my research showed to be still functional today. It was important for me to go through a design process for a piece of furniture from start to finish. Starting with exploration driven by curiosity and open-mindedness, the goal was to advance through a work process involving sketches, notes, mock-ups, prototypes, and discussions, among other things, leading to the point where I am in the workshop, attempting to realize this idea of a table in full scale. My goal is to personally develop more knowledge about a piece of furniture, its relation to the field, and how I work. I discovered a newfound admiration for furniture thanks to this deep dive and gained an understanding of the work involved. Therefore, I believe this project has given me the opportunity to become a better interior architect and furniture designer.

Detta examensarbete vid Konstfack inom Inredningsarkitektur och Möbeldesign har kommit att handla om en vilja att lära sig något nytt och utmanas inom det en tidigare inte gjort. Inom arbetet har det kommit att bli en undersökning av ett Perstorpsbord från 1960-talet. Det har varit en källa till inspiration och visat på lärdomar inom möbelkonstruktion och möbelformgivning. Projektets tyngd ligger i att förstå och se samband mellan de två aspekterna. Med detta som grund har en transformation skett där Perstorpsbordet har kommit att bli ett nytt, med förändringar inom form, material och konstruktion. Avsikten har varit att gestalta det nya bordet kallat NAVET, för en ungdom som ofta flyttar emellan boenden. Med det i åtanke så har behov av bordet blivit fastställda som sedan kommit att bli en del av utformningen. Jag jobbar med Perstorpsbordets befintliga funktioner samtidigt som det ska placeras i samtiden och därmed utvecklas. Därav ändras bordets form, material och kulör, samtidigt som jag behåller de aspekter med Perstorpsbordet som utifrån mina undersökningar ansågs vara fungerande hos bordet ännu idag. Det var viktigt för mig att gå igenom en gestaltningsprocess av en möbel från start till slut. Från ett undersökande med nyfikenhet och öppna ögon, så var syftet att ta det vidare igenom en process av arbete som skisser, anteckningar, mock-up, prototyper och samtal med mera. För att leda fram till att själv stå i verkstaden och försöka förverkliga denna idé av ett bord i full skala. Mitt mål är att personligen utveckla mer kunskap om såväl en möbel, som dess relation till fältet samt hur jag själv jobbar. Jag upptäckte en för mig ny förundran inför möbler tack vare denna djupdykning och en förståelse för det arbete som ligger bakom. Jag anser därför att detta projekt har gett mig möjligheten att bli bättre som inredningsarkitekt och möbeldesigner., This thesis project at Konstfack in Interior Architecture and Furniture Design has centered on a desire to learn something new and be challenged in areas I have not previously explored. During this work, it has become an investigation of a Perstorp table from the 1960s. It has been a source of inspiration, providing insights into furniture construction and design. The project’s core lies in understanding and seeing the connections between these two aspects. Using this as a foundation, a transformation has taken place where the Perstorp table has become a new piece, with changes in form, material, and construction. The intention has been to design the new table, called NAVET (The Hub), for a young person who frequently moves between homes. With this in mind, the needs of the table were identified and subsequently incorporated into the design. I am working with the existing functions of the Perstorp table while also aiming to place it in a contemporary context and thus develop it further. Therefore, the table’s shape, material, and color have been changed, while retaining the aspects of the Perstorp table that my research showed to be still functional today. It was important for me to go through a design process for a piece of furniture from start to finish. Starting with exploration driven by curiosity and open-mindedness, the goal was to advance through a work process involving sketches, notes, mock-ups, prototypes, and discussions, among other things, leading to the point where I am in the workshop, attempting to realize this idea of a table in full scale. My goal is to personally develop more knowledge about a piece of furniture, its relation to the field, and how I work. I discovered a newfound admiration for furniture thanks to this deep dive and gained an understanding of the work involved. Therefore, I believe this project has given me the opportunity to become a better interior architect and furniture designer.

This article explores wood-fiber-based fabrics containing Lyocell yarn in the warp and Spinnova–Lyocell (60%/40%) yarn in the weft, which are used to form unidirectional all-cellulose composites (ACC) through partial dilution in a NaOH–urea solution. The aim is to investigate the role of the yarn orientation in composites, which was conducted by measuring the tensile properties in both the 0° and 90° directions. As a reference, thermoplastic biocomposites were prepared from the same fabrics, with biobased polypropylene (PP) as the matrix. We also compared the mechanical and thermal properties of the ACC and PP biocomposites. The following experiments were carried out: tensile test, TGA, DSC, DMA, water absorption test and SEM. The study found no significant difference in tensile strength regarding the Spinnova–Lyocell orientation between ACC and PP biocomposites, while the composite tensile strength was clearly higher in the warp (Lyocell) direction for both composite variants. Elongation at break doubled in ACC in the Lyocell direction compared with the other samples. Thermal analysis showed that mass reduction started at a lower temperature for ACC, but the thermal stability was higher compared with the PP biocomposites. Maximum thermal degradation temperature was measured as being 352 °C for ACC and 466 °C for neat PP, and the PP biocomposites had two peaks in the same temperature range (340–474 °C) as ACC and neat PP combined. ACCs absorbed 93% of their own dry weight in water in just one hour, whereas the PP biocomposites BC2 and BC4 absorbed only 10% and 6%, respectively. The study highlights the different properties of ACC and PP reference biocomposites that could lead to further development and research of commercial applications for ACC.

En av grundpelarna i alla hållbara system är införandet av en cirkulär ekonomi, som främjar återanvändning och återvinning av material. Plast är en av i utmaning i detta avseende på grund av den stora produktionsvolymen variation i sorter och långsamma nedbrytn. Ett förslag till lösning på dessa problem, som det har forskats allt mer om under de senaste decennierna, är att ersätta syntetiska plaster med lämpliga biobaserade alternativ. Detta arbete syftade till att utforska två möjligheter i detta avseende, (1) Transparent trä (TW) och (2) Lim för trä från en förnybar källa. Utvärderingen av chitosan som ersättning för de syntetiska delarna av dessa material var det primära syftet med denna studie. TW utnyttjar de inneboende önskvärda egenskaperna hos trä och ökar dess användningsområden genom att ändra dess optiska egenskaper, men behöver en impregneringsmatris, som är en syntetisk polymer, för sin tillverkning. I detta arbete studerades variationen av kitosanimpregnering med tryck och torkningsförhållanden. Mikroskopi, gravimetri, kontaktvinkel och dynamisk mekanisk analys användes för att mäta effektiviteten hos de utvecklade metoderna. Alternativ till syntetiska lim för trä och träkompositer behövs på grund av problem med toxicitet. Chitosans användbarhet som lim för trä har dokumenterats i stor utsträckning. Det har dock inte gjorts så mycket arbete med trälaminat, som valdes som en ett sekundärt fokus för detta arbete. Testning av limmet utfördes med hjälp av skjuvmätningar. Resultaten visade att kitosan, istället för att infiltrera trästrukturen, främst deponerades på dess yta och specifika tester för att bestämma laminatets hållfasthet föll utanför ramen för denna studie., One of the mainstays of any sustainable system is the implementation of a circular economy, which promotes the reuse and recycling of materials. Plastics are one of the most problematic entities in this regard because of the sheer scale of production, their variety, and their recalcitrant nature. A proposed solution to this problem, one which has seen increasing research in the past decades, is replacing synthetic plastics with suitable bio-based alternatives. This work aimed to explore two possibilities in this regard, (1) Transparent wood (TW) and (2) Adhesives for wood. Evaluating the utility of chitosan as a replacement for the synthetic portions of these materials was the primary aim of this study. TW utilizes the inherently desirable properties of wood and increases its avenues of application by changing its optical properties but needs an impregnation matrix, which is a synthetic polymer, for fabrication. This work studied the variation of chitosan impregnation with pressure and drying conditions. Microscopy, gravimetry, water contact angle and dynamic mechanical analysis were used to gauge the efficacy of our methods. Alternatives to synthetic adhesives for wood and wood-composites are needed because of their associated problems with toxicity. Chitosan’s utility as an adhesive for wood has been documented to a considerable extent. However, not much work has been done with wood laminates, which were chosen as a secondary focal point of this work. Adhesive testing was carried out via lap-shear measurements. Results indicated that chitosan, instead of infiltrating the wood structure, was primarily deposited on its surface and specific tests for determining laminate strength fell out of the scope of this study.

This article explores wood-fiber-based fabrics containing Lyocell yarn in the warp and Spinnova–Lyocell (60%/40%) yarn in the weft, which are used to form unidirectional all-cellulose composites (ACC) through partial dilution in a NaOH–urea solution. The aim is to investigate the role of the yarn orientation in composites, which was conducted by measuring the tensile properties in both the 0° and 90° directions. As a reference, thermoplastic biocomposites were prepared from the same fabrics, with biobased polypropylene (PP) as the matrix. We also compared the mechanical and thermal properties of the ACC and PP biocomposites. The following experiments were carried out: tensile test, TGA, DSC, DMA, water absorption test and SEM. The study found no significant difference in tensile strength regarding the Spinnova–Lyocell orientation between ACC and PP biocomposites, while the composite tensile strength was clearly higher in the warp (Lyocell) direction for both composite variants. Elongation at break doubled in ACC in the Lyocell direction compared with the other samples. Thermal analysis showed that mass reduction started at a lower temperature for ACC, but the thermal stability was higher compared with the PP biocomposites. Maximum thermal degradation temperature was measured as being 352 °C for ACC and 466 °C for neat PP, and the PP biocomposites had two peaks in the same temperature range (340–474 °C) as ACC and neat PP combined. ACCs absorbed 93% of their own dry weight in water in just one hour, whereas the PP biocomposites BC2 and BC4 absorbed only 10% and 6%, respectively. The study highlights the different properties of ACC and PP reference biocomposites that could lead to further development and research of commercial applications for ACC.

En av grundpelarna i alla hållbara system är införandet av en cirkulär ekonomi, som främjar återanvändning och återvinning av material. Plast är en av i utmaning i detta avseende på grund av den stora produktionsvolymen variation i sorter och långsamma nedbrytn. Ett förslag till lösning på dessa problem, som det har forskats allt mer om under de senaste decennierna, är att ersätta syntetiska plaster med lämpliga biobaserade alternativ. Detta arbete syftade till att utforska två möjligheter i detta avseende, (1) Transparent trä (TW) och (2) Lim för trä från en förnybar källa. Utvärderingen av chitosan som ersättning för de syntetiska delarna av dessa material var det primära syftet med denna studie. TW utnyttjar de inneboende önskvärda egenskaperna hos trä och ökar dess användningsområden genom att ändra dess optiska egenskaper, men behöver en impregneringsmatris, som är en syntetisk polymer, för sin tillverkning. I detta arbete studerades variationen av kitosanimpregnering med tryck och torkningsförhållanden. Mikroskopi, gravimetri, kontaktvinkel och dynamisk mekanisk analys användes för att mäta effektiviteten hos de utvecklade metoderna. Alternativ till syntetiska lim för trä och träkompositer behövs på grund av problem med toxicitet. Chitosans användbarhet som lim för trä har dokumenterats i stor utsträckning. Det har dock inte gjorts så mycket arbete med trälaminat, som valdes som en ett sekundärt fokus för detta arbete. Testning av limmet utfördes med hjälp av skjuvmätningar. Resultaten visade att kitosan, istället för att infiltrera trästrukturen, främst deponerades på dess yta och specifika tester för att bestämma laminatets hållfasthet föll utanför ramen för denna studie., One of the mainstays of any sustainable system is the implementation of a circular economy, which promotes the reuse and recycling of materials. Plastics are one of the most problematic entities in this regard because of the sheer scale of production, their variety, and their recalcitrant nature. A proposed solution to this problem, one which has seen increasing research in the past decades, is replacing synthetic plastics with suitable bio-based alternatives. This work aimed to explore two possibilities in this regard, (1) Transparent wood (TW) and (2) Adhesives for wood. Evaluating the utility of chitosan as a replacement for the synthetic portions of these materials was the primary aim of this study. TW utilizes the inherently desirable properties of wood and increases its avenues of application by changing its optical properties but needs an impregnation matrix, which is a synthetic polymer, for fabrication. This work studied the variation of chitosan impregnation with pressure and drying conditions. Microscopy, gravimetry, water contact angle and dynamic mechanical analysis were used to gauge the efficacy of our methods. Alternatives to synthetic adhesives for wood and wood-composites are needed because of their associated problems with toxicity. Chitosan’s utility as an adhesive for wood has been documented to a considerable extent. However, not much work has been done with wood laminates, which were chosen as a secondary focal point of this work. Adhesive testing was carried out via lap-shear measurements. Results indicated that chitosan, instead of infiltrating the wood structure, was primarily deposited on its surface and specific tests for determining laminate strength fell out of the scope of this study.

An equivalent single layer approach to model fracture events of multidirectional balanced thin-ply laminates via the use of the Phase Field method is explored. The inherent anisotropic nature of a multidirectional laminate is taken into account through the use of a structural tensor, defined from scaled directional vectors, which can account for the variation in fracture toughness of the laminates in varying directions. The scaling constants are defined using the lay-up of the laminate and the intra-laminar fracture toughness of the lamina, minimizing the number of input parameters required while also alleviating the structural tensor of a pure numerical and geometric meaning. They have a significant effect in the solution, and are here related to materials properties, not only providing a new perspective on their definition but also allowing the reduction of the number of numerical parameters used to calibrate the anisotropic PF model. The numerical implementation of the proposed formulation is performed using a simple and robust thermal analogy in Abaqus by exploiting the use of an anisotropic conductivity matrix that plays the role of the structural tensor in the anisotropic phase field formulation, which reduces the complexity of the simulations. Experimental results, based on open-hole tension and double edge-notched tension, are reproduced via simulation validating the model for size effects and for the response to off-axis loading. Successful prediction of notch size effects in multidirectional composite laminates is achieved by means of an equivalent single layer approach, incl. the off-axis open-hole tension strengths of a directional thin-ply laminate. All numerical strength predictions were well within acceptable errors of the respective experimental values.

An equivalent single layer approach to model fracture events of multidirectional balanced thin-ply laminates via the use of the Phase Field method is explored. The inherent anisotropic nature of a multidirectional laminate is taken into account through the use of a structural tensor, defined from scaled directional vectors, which can account for the variation in fracture toughness of the laminates in varying directions. The scaling constants are defined using the lay-up of the laminate and the intra-laminar fracture toughness of the lamina, minimizing the number of input parameters required while also alleviating the structural tensor of a pure numerical and geometric meaning. They have a significant effect in the solution, and are here related to materials properties, not only providing a new perspective on their definition but also allowing the reduction of the number of numerical parameters used to calibrate the anisotropic PF model. The numerical implementation of the proposed formulation is performed using a simple and robust thermal analogy in Abaqus by exploiting the use of an anisotropic conductivity matrix that plays the role of the structural tensor in the anisotropic phase field formulation, which reduces the complexity of the simulations. Experimental results, based on open-hole tension and double edge-notched tension, are reproduced via simulation validating the model for size effects and for the response to off-axis loading. Successful prediction of notch size effects in multidirectional composite laminates is achieved by means of an equivalent single layer approach, incl. the off-axis open-hole tension strengths of a directional thin-ply laminate. All numerical strength predictions were well within acceptable errors of the respective experimental values.

An equivalent single layer approach to model fracture events of multidirectional balanced thin-ply laminates via the use of the Phase Field method is explored. The inherent anisotropic nature of a multidirectional laminate is taken into account through the use of a structural tensor, defined from scaled directional vectors, which can account for the variation in fracture toughness of the laminates in varying directions. The scaling constants are defined using the lay-up of the laminate and the intra-laminar fracture toughness of the lamina, minimizing the number of input parameters required while also alleviating the structural tensor of a pure numerical and geometric meaning. They have a significant effect in the solution, and are here related to materials properties, not only providing a new perspective on their definition but also allowing the reduction of the number of numerical parameters used to calibrate the anisotropic PF model. The numerical implementation of the proposed formulation is performed using a simple and robust thermal analogy in Abaqus by exploiting the use of an anisotropic conductivity matrix that plays the role of the structural tensor in the anisotropic phase field formulation, which reduces the complexity of the simulations. Experimental results, based on open-hole tension and double edge-notched tension, are reproduced via simulation validating the model for size effects and for the response to off-axis loading. Successful prediction of notch size effects in multidirectional composite laminates is achieved by means of an equivalent single layer approach, incl. the off-axis open-hole tension strengths of a directional thin-ply laminate. All numerical strength predictions were well within acceptable errors of the respective experimental values.

This paper presents a multi-scale procedure for the study of flat composite structures with discontinuities. In this procedure, the structure is solved using shell elements while the laminate performance and the structural discontinuities (e.g. connections or change in the laminate thickness) are analysed with a subscale model made with solid 3D elements. The kinematics of both models are coupled following the Kirchhoff–Love theory. This coupling is used during the homogenization procedure where the characteristic behavior of the different micro-models is obtained. Periodical boundary conditions are used for the laminates whereas a combination between periodical and linear boundary conditions are used for the discontinuities. The proposed procedure allows to reproduce accurately the structure elastic behaviour, as well as the stress and strain states in regions with discontinuities, which until now could only be accurately simulated by means of expensive numerical models using volumetric solid elements., This work has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement № 101006860 (FIBRE4YARDS project) and under grant agreement № 952966 (FIBREGY project). In addition, this research work is framed within an FI doctoral grant awarded by the Generalitat de Catalunya and co-financed jointly with the European Union . These supports are gratefully acknowledged., Peer Reviewed, Postprint (published version)

This article explores wood-fiber-based fabrics containing Lyocell yarn in the warp and Spinnova–Lyocell (60%/40%) yarn in the weft, which are used to form unidirectional all-cellulose composites (ACC) through partial dilution in a NaOH–urea solution. The aim is to investigate the role of the yarn orientation in composites, which was conducted by measuring the tensile properties in both the 0° and 90° directions. As a reference, thermoplastic biocomposites were prepared from the same fabrics, with biobased polypropylene (PP) as the matrix. We also compared the mechanical and thermal properties of the ACC and PP biocomposites. The following experiments were carried out: tensile test, TGA, DSC, DMA, water absorption test and SEM. The study found no significant difference in tensile strength regarding the Spinnova–Lyocell orientation between ACC and PP biocomposites, while the composite tensile strength was clearly higher in the warp (Lyocell) direction for both composite variants. Elongation at break doubled in ACC in the Lyocell direction compared with the other samples. Thermal analysis showed that mass reduction started at a lower temperature for ACC, but the thermal stability was higher compared with the PP biocomposites. Maximum thermal degradation temperature was measured as being 352 °C for ACC and 466 °C for neat PP, and the PP biocomposites had two peaks in the same temperature range (340–474 °C) as ACC and neat PP combined. ACCs absorbed 93% of their own dry weight in water in just one hour, whereas the PP biocomposites BC2 and BC4 absorbed only 10% and 6%, respectively. The study highlights the different properties of ACC and PP reference biocomposites that could lead to further development and research of commercial applications for ACC.

The so-called matrix failure, also named inter-fibre failure, is one of the main failure mechanisms in long fibre reinforced polymers (LFRPs). This mechanism is characterized by the debonding of some fibres when transverse loads are diving the failure process. In the present study, the prediction of cracks initiation and growth within fibre–matrix interfaces of the 90° layer in [0,90n]s laminates is aimed. To this end, the behaviour of the fibre–matrix interface is characterized using a Linear Elastic Brittle Interface Model (LEBIM) that has been implemented in the commercial FEA code Abaqus ® and applying a solution algorithm built in Python called the Sequentially Linear Analysis (SLA). The results point out the capability of the debonding process to represent the generation of transverse cracks, showing how the onset and growth of interface cracks within a laminate are influenced by different factors such as the local distribution of fibres, the value of the fibre–matrix interfacial fracture properties and the thickness of the 90° layer.

There is a growing research and production interest for the application of lower-cost hybrid cross-laminated timber (CLT) panels composed of timber layers of dissimilar quality. Therefore, an approach for the design of cost-effective hybrid CLT panels in bending, based on the existing analytical and novel finite element procedures, is presented in the paper. The gamma-method, the extended gamma method, and the composite theory are applied in the analysis of square panels, while the finite element model based on the Reddy’s full layerwise theory is used for the complex-shape panels in bending. An extensive benchmark technical and economic study is performed for 25 CLT panels, considering various spans, lamination schemes, geometries, and boundary conditions. Cost savings made by using a lower timber class in central zones of CLT panels are highlighted and quantified. This concept shows an economic potential that should be considered during the design and production of CLT panels in structural engineering applications, such as lightweight floor structures.

Composite solutions for marine applications - KOMPIS. Extensive research has been devoted to improving commercial shipping’s environmental footprint by focusing on lightweight constructions during the past decade. The biggest challenge to replacing steel structures with fibre-reinforced polymer (FRP) is ensuring fire safety at sea. Ongoing electrification and its dependence on weight reduction has further increased the demand for lightweight solutions, and in particular composite solutions that provide satisfactory fire safety. The purpose of this study was to inform regional actors concerning the feasibility of FRP composite in ship structures to respond to the growing demand for fire-safe composite materials, and as a step towards more environmentally friendly vessels. Within the project, a comprehensive literature study was conducted to find available components for a composite laminate on the market. A comprehensive list with polymers, fibres and additives was compiled. A hybrid composite laminate consisting of fenol/glass and vinylester/glass was manufactured and protected with an intumescent coating. The composite laminate was evaluated with regards to fire performance and mechanical properties. The results showed no ignition in the fire testing and good mechanical performance., Projektet KOMPIS – Kompositlösningar inom sjöfarten, har erhållit finansiering från Västra Götalandsregionen enligt diarienummer RUN 2010-00520.

The so-called matrix failure, also named inter-fibre failure, is one of the main failure mechanisms in long fibre reinforced polymers (LFRPs). This mechanism is characterized by the debonding of some fibres when transverse loads are diving the failure process. In the present study, the prediction of cracks initiation and growth within fibre–matrix interfaces of the 90° layer in [0,90n]s laminates is aimed. To this end, the behaviour of the fibre–matrix interface is characterized using a Linear Elastic Brittle Interface Model (LEBIM) that has been implemented in the commercial FEA code Abaqus ® and applying a solution algorithm built in Python called the Sequentially Linear Analysis (SLA). The results point out the capability of the debonding process to represent the generation of transverse cracks, showing how the onset and growth of interface cracks within a laminate are influenced by different factors such as the local distribution of fibres, the value of the fibre–matrix interfacial fracture properties and the thickness of the 90° layer.

The so-called matrix failure, also named inter-fibre failure, is one of the main failure mechanisms in long fibre reinforced polymers (LFRPs). This mechanism is characterized by the debonding of some fibres when transverse loads are diving the failure process. In the present study, the prediction of cracks initiation and growth within fibre–matrix interfaces of the 90° layer in [0,90n]s laminates is aimed. To this end, the behaviour of the fibre–matrix interface is characterized using a Linear Elastic Brittle Interface Model (LEBIM) that has been implemented in the commercial FEA code Abaqus ® and applying a solution algorithm built in Python called the Sequentially Linear Analysis (SLA). The results point out the capability of the debonding process to represent the generation of transverse cracks, showing how the onset and growth of interface cracks within a laminate are influenced by different factors such as the local distribution of fibres, the value of the fibre–matrix interfacial fracture properties and the thickness of the 90° layer.

Composite solutions for marine applications - KOMPIS. Extensive research has been devoted to improving commercial shipping’s environmental footprint by focusing on lightweight constructions during the past decade. The biggest challenge to replacing steel structures with fibre-reinforced polymer (FRP) is ensuring fire safety at sea. Ongoing electrification and its dependence on weight reduction has further increased the demand for lightweight solutions, and in particular composite solutions that provide satisfactory fire safety. The purpose of this study was to inform regional actors concerning the feasibility of FRP composite in ship structures to respond to the growing demand for fire-safe composite materials, and as a step towards more environmentally friendly vessels. Within the project, a comprehensive literature study was conducted to find available components for a composite laminate on the market. A comprehensive list with polymers, fibres and additives was compiled. A hybrid composite laminate consisting of fenol/glass and vinylester/glass was manufactured and protected with an intumescent coating. The composite laminate was evaluated with regards to fire performance and mechanical properties. The results showed no ignition in the fire testing and good mechanical performance., Projektet KOMPIS – Kompositlösningar inom sjöfarten, har erhållit finansiering från Västra Götalandsregionen enligt diarienummer RUN 2010-00520.

The so-called matrix failure, also named inter-fibre failure, is one of the main failure mechanisms in long fibre reinforced polymers (LFRPs). This mechanism is characterized by the debonding of some fibres when transverse loads are diving the failure process. In the present study, the prediction of cracks initiation and growth within fibre–matrix interfaces of the 90° layer in [0,90n]s laminates is aimed. To this end, the behaviour of the fibre–matrix interface is characterized using a Linear Elastic Brittle Interface Model (LEBIM) that has been implemented in the commercial FEA code Abaqus ® and applying a solution algorithm built in Python called the Sequentially Linear Analysis (SLA). The results point out the capability of the debonding process to represent the generation of transverse cracks, showing how the onset and growth of interface cracks within a laminate are influenced by different factors such as the local distribution of fibres, the value of the fibre–matrix interfacial fracture properties and the thickness of the 90° layer.

Microstructural effects on the energy release rate and the mode mixity for tunneling cracks are investigated. A detailed microstructure is based on scanning electron microscopy of a real laminate. Based on a newly developed two-dimensional off-axis finite element formulation, the dependency of the Mode I, Mode II, and Mode III energy release rates on a range of different layup orientations are investigated. First, the influence of the fiber-matrix microstructures on the energy release rates is assessed and compared to results from homogenized models that exclude explicit representation of the microstructure. A finite element-based homogenization is found to provide consistent and accurate predictions, whereas analytical homogenization methods yield greater discrepancies with respect to a basic stress-based validation case and are thus not recommended in the context of tunneling crack modeling. Secondly, realistic non-straight crack shapes are included in the model resulting in similar energy release rates as for straight cracks in the corresponding fully homogenized models. However, modeling the realistic non-straight cracks without accounting for the specific microstructure provides too low energy release rates when compared to the realistic cases with microstructures.

The so-called matrix failure, also named inter-fibre failure, is one of the main failure mechanisms in long fibre reinforced polymers (LFRPs). This mechanism is characterized by the debonding of some fibres when transverse loads are diving the failure process. In the present study, the prediction of cracks initiation and growth within fibre–matrix interfaces of the 90° layer in [0,90n]s laminates is aimed. To this end, the behaviour of the fibre–matrix interface is characterized using a Linear Elastic Brittle Interface Model (LEBIM) that has been implemented in the commercial FEA code Abaqus ® and applying a solution algorithm built in Python called the Sequentially Linear Analysis (SLA). The results point out the capability of the debonding process to represent the generation of transverse cracks, showing how the onset and growth of interface cracks within a laminate are influenced by different factors such as the local distribution of fibres, the value of the fibre–matrix interfacial fracture properties and the thickness of the 90° layer.

There is a growing research and production interest for the application of lower-cost hybrid cross-laminated timber (CLT) panels composed of timber layers of dissimilar quality. Therefore, an approach for the design of cost-effective hybrid CLT panels in bending, based on the existing analytical and novel finite element procedures, is presented in the paper. The gamma-method, the extended gamma method, and the composite theory are applied in the analysis of square panels, while the finite element model based on the Reddy’s full layerwise theory is used for the complex-shape panels in bending. An extensive benchmark technical and economic study is performed for 25 CLT panels, considering various spans, lamination schemes, geometries, and boundary conditions. Cost savings made by using a lower timber class in central zones of CLT panels are highlighted and quantified. This concept shows an economic potential that should be considered during the design and production of CLT panels in structural engineering applications, such as lightweight floor structures.

Bamboo reinforced hybrid composites are needed in claim to progress use of polymer composite technology. This paper describes a hand lay-up laminate process using plain-woven bamboo/E-glass woven/epoxy hybrid composite with the Design of experiment (DOE) 2 factor with 3- level and analysis of variance (ANOVA) was implemented for an evaluation against how the bamboo and e-glass woven affect the mechanical properties of hybrid composite in various sequence. The present study considers influence of plain-woven bamboo and e-glass woven laminated hybrid composite towards its tensile and charpy impact test performance. The results show that the 2-layer composites withstood better tensile strengths 185.372 MPa for EG/BW/EG while charpy impact 158.224 KJ/m2 for EG/BW sequence respectively. Experiments results show that concentrate on both lay-up sequence and layers are important effect factors for tensile and charpy performance. It had been proven that both the layers and also the lay-up sequence demonstrated significantly different leads to terms of the mechanical performance.

Large displacement peel was studied for cases where a compliant substrate leads to a large value of the root rotation. An existing simplified beam model to calculate the peel fracture energy was modified to allow for a kinematic hardening beam model of the foil. The steady-state peel force and the root rotation were used as input data to the resulting analytical beam model. Test results from the literature were analysed. A more elaborate finite element model was also studied, using cohesive elements for the interface layer between the foil and the substrate. The cohesive zone parameters used were the fracture energy, the cohesive strength and a shape parameter. An optimization scheme for the cohesive zone parameters was developed and optimized against experimental steady-state peel force and root rotation. The optimization scheme was effective to characterize the cohesive parameters. The method yields similar values of fracture energy for the two peel angles, with the one for being slightly higher than for . The difference in fracture energies for different peel angles suggests that the fracture energy can be mode dependent., CC BY 4.0Published online: 15 Dec 2019

Large displacement peel was studied for cases where a compliant substrate leads to a large value of the root rotation. An existing simplified beam model to calculate the peel fracture energy was modified to allow for a kinematic hardening beam model of the foil. The steady-state peel force and the root rotation were used as input data to the resulting analytical beam model. Test results from the literature were analysed. A more elaborate finite element model was also studied, using cohesive elements for the interface layer between the foil and the substrate. The cohesive zone parameters used were the fracture energy, the cohesive strength and a shape parameter. An optimization scheme for the cohesive zone parameters was developed and optimized against experimental steady-state peel force and root rotation. The optimization scheme was effective to characterize the cohesive parameters. The method yields similar values of fracture energy for the two peel angles, with the one for being slightly higher than for . The difference in fracture energies for different peel angles suggests that the fracture energy can be mode dependent., CC BY 4.0Published online: 15 Dec 2019

In this dissertation, the mechanical behaviour of 2-bolted single-lap Aluminum glassfiber composite plate with high strength bolts is investigated, both analytically and experimentally. A detailed 3D non-linear FE model of composite bolted joints has been developed. The model replicates with good agreement the experimental tensile tests up to the point where bearing damage occurs and reproduces the joint behaviour correctly. The evolution of contact during the test is studied showing a correlation with the joint stiffness. Using the developed FE model, the distribution of the stress components around the holes of the composite joints is studied together with the effects of hole clearance and position of bolts. The stress along the fibres is identified as the critical stress component and the compressive fibre failure of the 0° oriented plies as the start of the bearing damage. The 0° oriented plies in the cylindrical part of the hole are found to be the plies carrying the bearing load. Increasing clearance reduces the extent of the bolt shank-hole contact and leads to higher stresses and lower joint stiffness. The 45° and -45° oriented plies are found to have a key role in the joint bearing strength and shear-out failure.

In this dissertation, the mechanical behaviour of 2-bolted single-lap Aluminum glassfiber composite plate with high strength bolts is investigated, both analytically and experimentally. A detailed 3D non-linear FE model of composite bolted joints has been developed. The model replicates with good agreement the experimental tensile tests up to the point where bearing damage occurs and reproduces the joint behaviour correctly. The evolution of contact during the test is studied showing a correlation with the joint stiffness. Using the developed FE model, the distribution of the stress components around the holes of the composite joints is studied together with the effects of hole clearance and position of bolts. The stress along the fibres is identified as the critical stress component and the compressive fibre failure of the 0° oriented plies as the start of the bearing damage. The 0° oriented plies in the cylindrical part of the hole are found to be the plies carrying the bearing load. Increasing clearance reduces the extent of the bolt shank-hole contact and leads to higher stresses and lower joint stiffness. The 45° and -45° oriented plies are found to have a key role in the joint bearing strength and shear-out failure.

In this dissertation, the mechanical behaviour of 2-bolted single-lap Aluminum glassfiber composite plate with high strength bolts is investigated, both analytically and experimentally. A detailed 3D non-linear FE model of composite bolted joints has been developed. The model replicates with good agreement the experimental tensile tests up to the point where bearing damage occurs and reproduces the joint behaviour correctly. The evolution of contact during the test is studied showing a correlation with the joint stiffness. Using the developed FE model, the distribution of the stress components around the holes of the composite joints is studied together with the effects of hole clearance and position of bolts. The stress along the fibres is identified as the critical stress component and the compressive fibre failure of the 0° oriented plies as the start of the bearing damage. The 0° oriented plies in the cylindrical part of the hole are found to be the plies carrying the bearing load. Increasing clearance reduces the extent of the bolt shank-hole contact and leads to higher stresses and lower joint stiffness. The 45° and -45° oriented plies are found to have a key role in the joint bearing strength and shear-out failure.

In this dissertation, the mechanical behaviour of 2-bolted single-lap Aluminum glassfiber composite plate with high strength bolts is investigated, both analytically and experimentally. A detailed 3D non-linear FE model of composite bolted joints has been developed. The model replicates with good agreement the experimental tensile tests up to the point where bearing damage occurs and reproduces the joint behaviour correctly. The evolution of contact during the test is studied showing a correlation with the joint stiffness. Using the developed FE model, the distribution of the stress components around the holes of the composite joints is studied together with the effects of hole clearance and position of bolts. The stress along the fibres is identified as the critical stress component and the compressive fibre failure of the 0° oriented plies as the start of the bearing damage. The 0° oriented plies in the cylindrical part of the hole are found to be the plies carrying the bearing load. Increasing clearance reduces the extent of the bolt shank-hole contact and leads to higher stresses and lower joint stiffness. The 45° and -45° oriented plies are found to have a key role in the joint bearing strength and shear-out failure.

In this dissertation, the mechanical behaviour of 2-bolted single-lap Aluminum glassfiber composite plate with high strength bolts is investigated, both analytically and experimentally. A detailed 3D non-linear FE model of composite bolted joints has been developed. The model replicates with good agreement the experimental tensile tests up to the point where bearing damage occurs and reproduces the joint behaviour correctly. The evolution of contact during the test is studied showing a correlation with the joint stiffness. Using the developed FE model, the distribution of the stress components around the holes of the composite joints is studied together with the effects of hole clearance and position of bolts. The stress along the fibres is identified as the critical stress component and the compressive fibre failure of the 0° oriented plies as the start of the bearing damage. The 0° oriented plies in the cylindrical part of the hole are found to be the plies carrying the bearing load. Increasing clearance reduces the extent of the bolt shank-hole contact and leads to higher stresses and lower joint stiffness. The 45° and -45° oriented plies are found to have a key role in the joint bearing strength and shear-out failure.

In this dissertation, the mechanical behaviour of 2-bolted single-lap Aluminum glassfiber composite plate with high strength bolts is investigated, both analytically and experimentally. A detailed 3D non-linear FE model of composite bolted joints has been developed. The model replicates with good agreement the experimental tensile tests up to the point where bearing damage occurs and reproduces the joint behaviour correctly. The evolution of contact during the test is studied showing a correlation with the joint stiffness. Using the developed FE model, the distribution of the stress components around the holes of the composite joints is studied together with the effects of hole clearance and position of bolts. The stress along the fibres is identified as the critical stress component and the compressive fibre failure of the 0° oriented plies as the start of the bearing damage. The 0° oriented plies in the cylindrical part of the hole are found to be the plies carrying the bearing load. Increasing clearance reduces the extent of the bolt shank-hole contact and leads to higher stresses and lower joint stiffness. The 45° and -45° oriented plies are found to have a key role in the joint bearing strength and shear-out failure.

U ovom radu sprovedena je analiza inicijacije loma laminatne kompozitne ploče, koristeći slojeviti konačni element zasnovan na Redijevoj slojevitoj teoriji ploča. Sračunato je granično opterećenje na osnovu nekoliko različitih kriterijuma loma koji su implementirani u proračunski model. U radu je izvršena probabilistička analiza loma, u kojoj su materijalne karakteristike i čvrstoća lamine usvojene kao slučajno promenljive veličine. Cilj analize, zasnovane na Monte Karlo metodi, je sračunavanje statističkih parametara graničnog opterećenja kompozitnog laminata. Na osnovu sprovedene analize izvedeni su odgovarajući zaključci., The paper deals with the first-ply failure analysis of laminated composite plates using a layered finite element model based on the Full layerwise theory of Reddy (FLWT). Several macroscopic failure criteria have been incorporated into computational model and used to compute the limit load. Since almost no parameter in failure analysis is deterministic, probability prediction of limit load, considering the lamina elastic material properties and strength as random variables is developed. The aim of analysis, based on Monte Carlo Method, is to calculate statistical parameters of the limit load of composite laminate. Appropriate conclusions have been derived based on the conducted analysis.

In this dissertation, the mechanical behaviour of 2-bolted single-lap Aluminum glassfiber composite plate with high strength bolts is investigated, both analytically and experimentally. A detailed 3D non-linear FE model of composite bolted joints has been developed. The model replicates with good agreement the experimental tensile tests up to the point where bearing damage occurs and reproduces the joint behaviour correctly. The evolution of contact during the test is studied showing a correlation with the joint stiffness. Using the developed FE model, the distribution of the stress components around the holes of the composite joints is studied together with the effects of hole clearance and position of bolts. The stress along the fibres is identified as the critical stress component and the compressive fibre failure of the 0° oriented plies as the start of the bearing damage. The 0° oriented plies in the cylindrical part of the hole are found to be the plies carrying the bearing load. Increasing clearance reduces the extent of the bolt shank-hole contact and leads to higher stresses and lower joint stiffness. The 45° and -45° oriented plies are found to have a key role in the joint bearing strength and shear-out failure.

Liquid food packages consist of various polymers films, which are bonded together with Aluminum foil (Al-foil) using adhesion or by direct heat. The main aim of this research was to define important material properties such as fracture toughness and some FE-simulation material model parameters such as damage initiation, damage evolution, and the adhesion between Al-foil and low-density polyethylene (LDPE) film. This investigation is based on both physical experiments and FE simulations in ABAQUS with and without initial cracks of different lengths for comparison purposes. The final FE model in ABAQUS was used to compare the numerical input parameters in an extensive study with the ambition to investigate the materials’ parameters in cases with or without adhesion between laminates. Finally, the relation between the theoretical and experimental results for Al-foil using linear elastic fracture mechanics and modified strip yield model were shown, and the fracture toughness was calculated for two different thicknesses of Al-foil. © 2021 by the authors. Licensee MDPI, Basel, Switzerland., open access

Liquid food packages consist of various polymers films, which are bonded together with Aluminum foil (Al-foil) using adhesion or by direct heat. The main aim of this research was to define important material properties such as fracture toughness and some FE-simulation material model parameters such as damage initiation, damage evolution, and the adhesion between Al-foil and low-density polyethylene (LDPE) film. This investigation is based on both physical experiments and FE simulations in ABAQUS with and without initial cracks of different lengths for comparison purposes. The final FE model in ABAQUS was used to compare the numerical input parameters in an extensive study with the ambition to investigate the materials’ parameters in cases with or without adhesion between laminates. Finally, the relation between the theoretical and experimental results for Al-foil using linear elastic fracture mechanics and modified strip yield model were shown, and the fracture toughness was calculated for two different thicknesses of Al-foil. © 2021 by the authors. Licensee MDPI, Basel, Switzerland., open access

A multiscale approach comprising laminate-scale finite-element (FE) analysis and fiber-diameter-scale periodic unit cell (PUC) analysis was developed to predict matrix microcracking in quasiisotropic laminates; further, this method was validated through comparison of our predictions with experimental results. In the mesoscopic FE analysis, the nonlinear deformation in the unidirectional laminae was incorporated to reproduce the deformation behavior of the laminate and obtain deformation histories at the locations of expected crack initiation in the laminate. In the microscopic analysis, the nonlinear behavior and crack initiation in the matrix resin were simply modeled by an elasto-viscoplastic law and a stress-based failure criterion, respectively. To predict crack initiation considering both the macroscopic deformation fields and the microscopic heterogeneity of the material, the mesoscopic FE analysis was conducted first. Subsequently, the microscopic PUC analysis was undertaken based on the strain histories obtained from the mesoscopic analysis. Our multiscale approach was applied to quasi-isotropic laminates with several laminate configurations to predict the matrix cracks in the 90° ply of the laminates. In addition to referring to experimental data cited in literature, initial and transverse cracks were observed when conducting tensile tests of quasi-isotropic laminates using the in situ replication technique and ex situ X-ray computed tomography. Through comparison of the predicted values with experimental results quoted in literature and obtained in this work,we validated the prediction capability of our multiscale analysis and evaluated the process of crack formation from the mesoscopic and microscopic points of view. Moreover, we examined the sensitivity of predicted results to fiber arrangement and the influence of constitutive and failure modeling of two-scale analysis on predicted cracking strains. The reported method can predict initial and transverse

U ovom radu sprovedena je analiza inicijacije loma laminatne kompozitne ploče, koristeći slojeviti konačni element zasnovan na Redijevoj slojevitoj teoriji ploča. Sračunato je granično opterećenje na osnovu nekoliko različitih kriterijuma loma koji su implementirani u proračunski model. U radu je izvršena probabilistička analiza loma, u kojoj su materijalne karakteristike i čvrstoća lamine usvojene kao slučajno promenljive veličine. Cilj analize, zasnovane na Monte Karlo metodi, je sračunavanje statističkih parametara graničnog opterećenja kompozitnog laminata. Na osnovu sprovedene analize izvedeni su odgovarajući zaključci., The paper deals with the first-ply failure analysis of laminated composite plates using a layered finite element model based on the Full layerwise theory of Reddy (FLWT). Several macroscopic failure criteria have been incorporated into computational model and used to compute the limit load. Since almost no parameter in failure analysis is deterministic, probability prediction of limit load, considering the lamina elastic material properties and strength as random variables is developed. The aim of analysis, based on Monte Carlo Method, is to calculate statistical parameters of the limit load of composite laminate. Appropriate conclusions have been derived based on the conducted analysis.

Large displacement peel was studied for cases where a compliant substrate leads to a large value of the root rotation. An existing simplified beam model to calculate the peel fracture energy was modified to allow for a kinematic hardening beam model of the foil. The steady-state peel force and the root rotation were used as input data to the resulting analytical beam model. Test results from the literature were analysed. A more elaborate finite element model was also studied, using cohesive elements for the interface layer between the foil and the substrate. The cohesive zone parameters used were the fracture energy, the cohesive strength and a shape parameter. An optimization scheme for the cohesive zone parameters was developed and optimized against experimental steady-state peel force and root rotation. The optimization scheme was effective to characterize the cohesive parameters. The method yields similar values of fracture energy for the two peel angles, with the one for being slightly higher than for . The difference in fracture energies for different peel angles suggests that the fracture energy can be mode dependent., CC BY 4.0Published online: 15 Dec 2019

Large displacement peel was studied for cases where a compliant substrate leads to a large value of the root rotation. An existing simplified beam model to calculate the peel fracture energy was modified to allow for a kinematic hardening beam model of the foil. The steady-state peel force and the root rotation were used as input data to the resulting analytical beam model. Test results from the literature were analysed. A more elaborate finite element model was also studied, using cohesive elements for the interface layer between the foil and the substrate. The cohesive zone parameters used were the fracture energy, the cohesive strength and a shape parameter. An optimization scheme for the cohesive zone parameters was developed and optimized against experimental steady-state peel force and root rotation. The optimization scheme was effective to characterize the cohesive parameters. The method yields similar values of fracture energy for the two peel angles, with the one for being slightly higher than for . The difference in fracture energies for different peel angles suggests that the fracture energy can be mode dependent., CC BY 4.0Published online: 15 Dec 2019

Bamboo reinforced hybrid composites are needed in claim to progress use of polymer composite technology. This paper describes a hand lay-up laminate process using plain-woven bamboo/E-glass woven/epoxy hybrid composite with the Design of experiment (DOE) 2 factor with 3- level and analysis of variance (ANOVA) was implemented for an evaluation against how the bamboo and e-glass woven affect the mechanical properties of hybrid composite in various sequence. The present study considers influence of plain-woven bamboo and e-glass woven laminated hybrid composite towards its tensile and charpy impact test performance. The results show that the 2-layer composites withstood better tensile strengths 185.372 MPa for EG/BW/EG while charpy impact 158.224 KJ/m2 for EG/BW sequence respectively. Experiments results show that concentrate on both lay-up sequence and layers are important effect factors for tensile and charpy performance. It had been proven that both the layers and also the lay-up sequence demonstrated significantly different leads to terms of the mechanical performance.

Liquid food packages consist of various polymers films, which are bonded together with Aluminum foil (Al-foil) using adhesion or by direct heat. The main aim of this research was to define important material properties such as fracture toughness and some FE-simulation material model parameters such as damage initiation, damage evolution, and the adhesion between Al-foil and low-density polyethylene (LDPE) film. This investigation is based on both physical experiments and FE simulations in ABAQUS with and without initial cracks of different lengths for comparison purposes. The final FE model in ABAQUS was used to compare the numerical input parameters in an extensive study with the ambition to investigate the materials’ parameters in cases with or without adhesion between laminates. Finally, the relation between the theoretical and experimental results for Al-foil using linear elastic fracture mechanics and modified strip yield model were shown, and the fracture toughness was calculated for two different thicknesses of Al-foil. © 2021 by the authors. Licensee MDPI, Basel, Switzerland., open access

Liquid food packages consist of various polymers films, which are bonded together with Aluminum foil (Al-foil) using adhesion or by direct heat. The main aim of this research was to define important material properties such as fracture toughness and some FE-simulation material model parameters such as damage initiation, damage evolution, and the adhesion between Al-foil and low-density polyethylene (LDPE) film. This investigation is based on both physical experiments and FE simulations in ABAQUS with and without initial cracks of different lengths for comparison purposes. The final FE model in ABAQUS was used to compare the numerical input parameters in an extensive study with the ambition to investigate the materials’ parameters in cases with or without adhesion between laminates. Finally, the relation between the theoretical and experimental results for Al-foil using linear elastic fracture mechanics and modified strip yield model were shown, and the fracture toughness was calculated for two different thicknesses of Al-foil. © 2021 by the authors. Licensee MDPI, Basel, Switzerland., open access

Liquid food packages consist of various polymers films, which are bonded together with Aluminum foil (Al-foil) using adhesion or by direct heat. The main aim of this research was to define important material properties such as fracture toughness and some FE-simulation material model parameters such as damage initiation, damage evolution, and the adhesion between Al-foil and low-density polyethylene (LDPE) film. This investigation is based on both physical experiments and FE simulations in ABAQUS with and without initial cracks of different lengths for comparison purposes. The final FE model in ABAQUS was used to compare the numerical input parameters in an extensive study with the ambition to investigate the materials’ parameters in cases with or without adhesion between laminates. Finally, the relation between the theoretical and experimental results for Al-foil using linear elastic fracture mechanics and modified strip yield model were shown, and the fracture toughness was calculated for two different thicknesses of Al-foil. © 2021 by the authors. Licensee MDPI, Basel, Switzerland., open access

Liquid food packages consist of various polymers films, which are bonded together with Aluminum foil (Al-foil) using adhesion or by direct heat. The main aim of this research was to define important material properties such as fracture toughness and some FE-simulation material model parameters such as damage initiation, damage evolution, and the adhesion between Al-foil and low-density polyethylene (LDPE) film. This investigation is based on both physical experiments and FE simulations in ABAQUS with and without initial cracks of different lengths for comparison purposes. The final FE model in ABAQUS was used to compare the numerical input parameters in an extensive study with the ambition to investigate the materials’ parameters in cases with or without adhesion between laminates. Finally, the relation between the theoretical and experimental results for Al-foil using linear elastic fracture mechanics and modified strip yield model were shown, and the fracture toughness was calculated for two different thicknesses of Al-foil. © 2021 by the authors. Licensee MDPI, Basel, Switzerland., open access

Large displacement peel was studied for cases where a compliant substrate leads to a large value of the root rotation. An existing simplified beam model to calculate the peel fracture energy was modified to allow for a kinematic hardening beam model of the foil. The steady-state peel force and the root rotation were used as input data to the resulting analytical beam model. Test results from the literature were analysed. A more elaborate finite element model was also studied, using cohesive elements for the interface layer between the foil and the substrate. The cohesive zone parameters used were the fracture energy, the cohesive strength and a shape parameter. An optimization scheme for the cohesive zone parameters was developed and optimized against experimental steady-state peel force and root rotation. The optimization scheme was effective to characterize the cohesive parameters. The method yields similar values of fracture energy for the two peel angles, with the one for being slightly higher than for . The difference in fracture energies for different peel angles suggests that the fracture energy can be mode dependent., CC BY 4.0Published online: 15 Dec 2019

The proposed material design of BaTiO3/Al2O3/ZrO2 laminate structure predetermined for energy harvesters taking advantage of residual stresses developed during processing was prepared by electrophoretic deposition. The main aim of developed residual stresses is to enhance overall mechanical reliability of piezoceramic functional layers and/or to enhance piezoelectric effects acting in the laminate. The concept of co-sintered BaTiO3 piezo ceramic functional layers with protective ZrO2 and Al2O3 layers is based on strongly bonded layers. In this contribution will be described particular behaviour of the specific material configuration BaTiO3/Al2O3 laminate where an interface interlayer among other effects was formed. The influence of sintering conditions on the microstructure development of the laminate as well as the formation of the interlayer was investigated. The relationship between observed microstructural changes and resulting mechanical properties as hardness and indentation elastic modulus was analyzed by means of nanoindentation technique. The cracks propagation through the individual layers and specific formed interfaces were observed and analyzed. The crack deflection due to the presence of developed residual stresses during the cooling stage of sintering as well as the consequence of microstructural changes on mechanical properties was confirmed.

The proposed material design of BaTiO3/Al2O3/ZrO2 laminate structure predetermined for energy harvesters taking advantage of residual stresses developed during processing was prepared by electrophoretic deposition. The main aim of developed residual stresses is to enhance overall mechanical reliability of piezoceramic functional layers and/or to enhance piezoelectric effects acting in the laminate. The concept of co-sintered BaTiO3 piezo ceramic functional layers with protective ZrO2 and Al2O3 layers is based on strongly bonded layers. In this contribution will be described particular behaviour of the specific material configuration BaTiO3/Al2O3 laminate where an interface interlayer among other effects was formed. The influence of sintering conditions on the microstructure development of the laminate as well as the formation of the interlayer was investigated. The relationship between observed microstructural changes and resulting mechanical properties as hardness and indentation elastic modulus was analyzed by means of nanoindentation technique. The cracks propagation through the individual layers and specific formed interfaces were observed and analyzed. The crack deflection due to the presence of developed residual stresses during the cooling stage of sintering as well as the consequence of microstructural changes on mechanical properties was confirmed.

Paper machine manufacturing of photocatalysts can enable low cost devices for removal of low concentratedpollutants. Lateral variations originating from the paper making process leads to variations of the catalyticactivity over the paper area. Paper machine manufactured papers made from tetrapodal ZnO whiskers and kraftpulp were investigated in this test geometry using simulated solar light. Photocatalytic ZnO papers were laminatedbetween polyethylene sheets and an indicator solution seeped into the laminated photocatalytic paper, tocreate a test geometry where the indicator ink is confined to a small volume between the polyethylene sheets.The photocatalyst papers exhibited surprisingly similar photocatalytic behavior although having different catalystloading 15, 30 and 45 wt percent. All papers exhibited lateral variations that peaked during the conversion.The results show that production of effective photocatalytic composite papers can be scaled.Further, the results show that variations must be considered for photocatalytic papers.

Paper machine manufacturing of photocatalysts can enable low cost devices for removal of low concentratedpollutants. Lateral variations originating from the paper making process leads to variations of the catalyticactivity over the paper area. Paper machine manufactured papers made from tetrapodal ZnO whiskers and kraftpulp were investigated in this test geometry using simulated solar light. Photocatalytic ZnO papers were laminatedbetween polyethylene sheets and an indicator solution seeped into the laminated photocatalytic paper, tocreate a test geometry where the indicator ink is confined to a small volume between the polyethylene sheets.The photocatalyst papers exhibited surprisingly similar photocatalytic behavior although having different catalystloading 15, 30 and 45 wt percent. All papers exhibited lateral variations that peaked during the conversion.The results show that production of effective photocatalytic composite papers can be scaled.Further, the results show that variations must be considered for photocatalytic papers.

The steady-state energy release rate for tunneling cracks under mixed-mode loading is determined using finite element analyses. The balanced and symmetric laminate layup [0/θ/0/-θ]s is investigated, where the tunneling crack is located parallel to the fiber direction of the central off-axis oriented layer. It is found that for the steady-state situation, a simple energy balance calculation of the released energy of the separated crack surfaces for a fully developed crack gives the same value as the average value of a detailed J-integral analysis of the crack front. Furthermore, the crack front mode-mixity, obtained by the same energy balance calculation, was found to give a good prediction of the average mode-mixity found from a detailed stress intensity calculation along the crack-tip. Based on this simplified energy balance approach, the energy release rate is determined for all angles θ ∈ ]0;90]∘for orthotropic elastic properties ranging from typical low modulus glass fiber reinforced polymers to high modulus carbon fiber reinforced polymers. The predicted results can be used to investigate the influence of the layup angles on static and fatigue tunnel crack evolution in composite materials used within, e.g. automotive, aerospace, and wind energy applications.

The proposed material design of BaTiO3/Al2O3/ZrO2 laminate structure predetermined for energy harvesters taking advantage of residual stresses developed during processing was prepared by electrophoretic deposition. The main aim of developed residual stresses is to enhance overall mechanical reliability of piezoceramic functional layers and/or to enhance piezoelectric effects acting in the laminate. The concept of co-sintered BaTiO3 piezo ceramic functional layers with protective ZrO2 and Al2O3 layers is based on strongly bonded layers. In this contribution will be described particular behaviour of the specific material configuration BaTiO3/Al2O3 laminate where an interface interlayer among other effects was formed. The influence of sintering conditions on the microstructure development of the laminate as well as the formation of the interlayer was investigated. The relationship between observed microstructural changes and resulting mechanical properties as hardness and indentation elastic modulus was analyzed by means of nanoindentation technique. The cracks propagation through the individual layers and specific formed interfaces were observed and analyzed. The crack deflection due to the presence of developed residual stresses during the cooling stage of sintering as well as the consequence of microstructural changes on mechanical properties was confirmed.