Journal of Sandwich Structures & Materials, 2016
Honeycomb sandwich structures are increasingly used in the automotive, aerospace and shipbuilding... more Honeycomb sandwich structures are increasingly used in the automotive, aerospace and shipbuilding industries where fuel savings, increase in load carrying capacity, vehicle safety and decrease in gas emissions are very important aspects. The aim of this study was to develop the theoretical methods, initially proposed by the authors and by other researchers for the prediction of low-velocity impact responses of sandwich structures. The developed methods were applied to sandwich structures with aluminium honeycomb cores and glass-epoxy facings for the assessment of impact parameters and for the prediction of limit loads. The values of model parameters were compared with data reported in literature and the predictions of the limit loads were validated by means of the experimental data. Good achievement was obtained between the results of the theoretical models and the experimental data. The failure mode and the internal damage of the sandwich panels have been investigated using 3D comp...
The structures obtained with the use of sandwich technologies combine low weight with high energy... more The structures obtained with the use of sandwich technologies combine low weight with high energy absorbing capacity and load carrying capacity. Hence, there is a growing and markedly interest in the use of sandwiches with aluminum foam core because of very good properties such as flexural rigidity and energy absorption capability. In the current investigation, the static threepoint bending tests were carried out on the sandwiches with aluminum foam core and glass fiber reinforced polymer (GFRP) skins at different values of support span distances aiming the analyses of their flexural performance. The influence of the core thickness and the GFRP skin type was reported in terms of peak load and energy absorption capacity. For this purpose, the skins with two different types of fabrics which have same thickness value and the aluminum foam core with two different thicknesses were bonded with a commercial polyurethane based flexible adhesive in order to combine the composite sandwich pan...
The material selection in the design of the sandwich<br> structures is very crucial aspect ... more The material selection in the design of the sandwich<br> structures is very crucial aspect because of the positive or negative<br> influences of the base materials to the mechanical properties of the<br> entire panel. In the literature, it was presented that the selection of the<br> skin and core materials plays very important role on the behavior of<br> the sandwich. Beside this, the use of the correct adhesive can make<br> the whole structure to show better mechanical results and behavior.<br> In the present work, the static three-point bending tests were<br> performed on the sandwiches having an aluminum alloy foam core,<br> the skins made of three different types of fabrics and two different<br> commercial adhesives (flexible polyurethane and toughened epoxy<br> based) at different values of support span distances by aiming the<br> analyses of their flexural performance in terms of absorbed energy,<br>...
Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 2015
The joining techniques of lightweight and strong materials in the transport industry (e.g. automo... more The joining techniques of lightweight and strong materials in the transport industry (e.g. automotive, aerospace, shipbuilding industries) are very important for the safety of the entire structure. In these industries, when compared with other joining methods, the use of adhesively bonded joints presents unique properties such as greater strength, design flexibility, and reduction in fuel consumption, all thanks to low weight. The aim of this study was the analysis of the tensile fatigue behavior of adhesively bonded glass fiber/epoxy laminated composite single-lap joints with three different specimen types including 30, 40 and 50 mm overlap lengths. In this study, composite adherents were manufactured via vacuum-assisted resin transfer molding and were bonded using Loctite 9461 A&B toughened epoxy adhesive. The effect of a surface treatment method on the bonding strength was considered and it led to an increment of about 40%. A numerical analysis based on a finite element model was...
While the polymeric foam cored sandwiches have been realized for many years, recently there is a ... more While the polymeric foam cored sandwiches have been realized for many years, recently there is a growing and outstanding interest on the use of sandwiches consisting of aluminum foam core because of their some of the distinct mechanical properties such as high bending stiffness, high load carrying and energy absorption capacities. These properties make them very useful in the transportation industry (automotive, aerospace, shipbuilding industry), where the "lightweight design" philosophy and the safety of vehicles are very important aspects. Therefore, in this study, the sandwich panels with aluminum alloy foam core and various types and thicknesses of glass fiber reinforced polymer (GFRP) skins produced via Vacuum Assisted Resin Transfer Molding (VARTM) technique were obtained by using a commercial toughened epoxy based adhesive with two components. The aim of this contribution was the analysis of the bending response of sandwiches with various glass fiber reinforced poly...
The joining techniques of lightweight and strong materials in the transport industry (e.g. automo... more The joining techniques of lightweight and strong materials in the transport industry (e.g. automotive, aerospace, shipbuilding industries) are very important for the safety of the entire structure. In these industries, when compared with other joining methods, the use of adhesively bonded joints presents unique properties such as greater strength, design flexibility, and reduction in fuel consumption, all thanks to low weight. The aim of this study was the analysis of the tensile fatigue behavior of adhesively bonded glass fiber/epoxy laminated composite single-lap joints with three different specimen types including 30, 40 and 50 mm overlap lengths. In this study, composite adherents were manufactured via vacuum-assisted resin transfer molding and were bonded using Loctite 9461 A&B toughened epoxy adhesive. The effect of a surface treatment method on the bonding strength was considered and it led to an increment of about 40%. A numerical analysis based on a finite element model was performed to predict fatigue life curve, and the predicted results showed good agreement with the experimental investigation.
The use of sandwich structures combines low weight with high energy absorbing capacity, so they a... more The use of sandwich structures combines low weight with high energy absorbing capacity, so they are suitable for applications in the transport industry (automotive, aerospace, shipbuilding industry), where the “lightweight design” philosophy and the safety of vehicles are very important aspects. The goal of this paper was the analysis of the bending and the low - velocity impact response of aluminium foam sandwiches reinforced by the outer skins made of glass fibre reinforced epoxy matrix. The results were compared with those obtained for aluminium foam sandwiches without glass fibre skins. An analytical model for the peak load prediction under low velocity impact was developed and the predicted values are in good agreement with the experimental measurements. The impact response of the sandwiches was investigated using a theoretical approach, based on the energy balance model and the model parameters were obtained by the tomographic analyses of the impacted panels. This combined experimental and theoretical investigation has particular importance for applications that require lightweight composite structures with a high capacity of energy dissipation, such as the transport industry, where problems of collision and crash have increased in the last years.
Journal of Sandwich Structures & Materials, 2016
Honeycomb sandwich structures are increasingly used in the automotive, aerospace and shipbuilding... more Honeycomb sandwich structures are increasingly used in the automotive, aerospace and shipbuilding industries where fuel savings, increase in load carrying capacity, vehicle safety and decrease in gas emissions are very important aspects. The aim of this study was to develop the theoretical methods, initially proposed by the authors and by other researchers for the prediction of low-velocity impact responses of sandwich structures. The developed methods were applied to sandwich structures with aluminium honeycomb cores and glass-epoxy facings for the assessment of impact parameters and for the prediction of limit loads. The values of model parameters were compared with data reported in literature and the predictions of the limit loads were validated by means of the experimental data. Good achievement was obtained between the results of the theoretical models and the experimental data. The failure mode and the internal damage of the sandwich panels have been investigated using 3D comp...
The structures obtained with the use of sandwich technologies combine low weight with high energy... more The structures obtained with the use of sandwich technologies combine low weight with high energy absorbing capacity and load carrying capacity. Hence, there is a growing and markedly interest in the use of sandwiches with aluminum foam core because of very good properties such as flexural rigidity and energy absorption capability. In the current investigation, the static threepoint bending tests were carried out on the sandwiches with aluminum foam core and glass fiber reinforced polymer (GFRP) skins at different values of support span distances aiming the analyses of their flexural performance. The influence of the core thickness and the GFRP skin type was reported in terms of peak load and energy absorption capacity. For this purpose, the skins with two different types of fabrics which have same thickness value and the aluminum foam core with two different thicknesses were bonded with a commercial polyurethane based flexible adhesive in order to combine the composite sandwich pan...
The material selection in the design of the sandwich<br> structures is very crucial aspect ... more The material selection in the design of the sandwich<br> structures is very crucial aspect because of the positive or negative<br> influences of the base materials to the mechanical properties of the<br> entire panel. In the literature, it was presented that the selection of the<br> skin and core materials plays very important role on the behavior of<br> the sandwich. Beside this, the use of the correct adhesive can make<br> the whole structure to show better mechanical results and behavior.<br> In the present work, the static three-point bending tests were<br> performed on the sandwiches having an aluminum alloy foam core,<br> the skins made of three different types of fabrics and two different<br> commercial adhesives (flexible polyurethane and toughened epoxy<br> based) at different values of support span distances by aiming the<br> analyses of their flexural performance in terms of absorbed energy,<br>...
Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 2015
The joining techniques of lightweight and strong materials in the transport industry (e.g. automo... more The joining techniques of lightweight and strong materials in the transport industry (e.g. automotive, aerospace, shipbuilding industries) are very important for the safety of the entire structure. In these industries, when compared with other joining methods, the use of adhesively bonded joints presents unique properties such as greater strength, design flexibility, and reduction in fuel consumption, all thanks to low weight. The aim of this study was the analysis of the tensile fatigue behavior of adhesively bonded glass fiber/epoxy laminated composite single-lap joints with three different specimen types including 30, 40 and 50 mm overlap lengths. In this study, composite adherents were manufactured via vacuum-assisted resin transfer molding and were bonded using Loctite 9461 A&B toughened epoxy adhesive. The effect of a surface treatment method on the bonding strength was considered and it led to an increment of about 40%. A numerical analysis based on a finite element model was...
While the polymeric foam cored sandwiches have been realized for many years, recently there is a ... more While the polymeric foam cored sandwiches have been realized for many years, recently there is a growing and outstanding interest on the use of sandwiches consisting of aluminum foam core because of their some of the distinct mechanical properties such as high bending stiffness, high load carrying and energy absorption capacities. These properties make them very useful in the transportation industry (automotive, aerospace, shipbuilding industry), where the "lightweight design" philosophy and the safety of vehicles are very important aspects. Therefore, in this study, the sandwich panels with aluminum alloy foam core and various types and thicknesses of glass fiber reinforced polymer (GFRP) skins produced via Vacuum Assisted Resin Transfer Molding (VARTM) technique were obtained by using a commercial toughened epoxy based adhesive with two components. The aim of this contribution was the analysis of the bending response of sandwiches with various glass fiber reinforced poly...
The joining techniques of lightweight and strong materials in the transport industry (e.g. automo... more The joining techniques of lightweight and strong materials in the transport industry (e.g. automotive, aerospace, shipbuilding industries) are very important for the safety of the entire structure. In these industries, when compared with other joining methods, the use of adhesively bonded joints presents unique properties such as greater strength, design flexibility, and reduction in fuel consumption, all thanks to low weight. The aim of this study was the analysis of the tensile fatigue behavior of adhesively bonded glass fiber/epoxy laminated composite single-lap joints with three different specimen types including 30, 40 and 50 mm overlap lengths. In this study, composite adherents were manufactured via vacuum-assisted resin transfer molding and were bonded using Loctite 9461 A&B toughened epoxy adhesive. The effect of a surface treatment method on the bonding strength was considered and it led to an increment of about 40%. A numerical analysis based on a finite element model was performed to predict fatigue life curve, and the predicted results showed good agreement with the experimental investigation.
The use of sandwich structures combines low weight with high energy absorbing capacity, so they a... more The use of sandwich structures combines low weight with high energy absorbing capacity, so they are suitable for applications in the transport industry (automotive, aerospace, shipbuilding industry), where the “lightweight design” philosophy and the safety of vehicles are very important aspects. The goal of this paper was the analysis of the bending and the low - velocity impact response of aluminium foam sandwiches reinforced by the outer skins made of glass fibre reinforced epoxy matrix. The results were compared with those obtained for aluminium foam sandwiches without glass fibre skins. An analytical model for the peak load prediction under low velocity impact was developed and the predicted values are in good agreement with the experimental measurements. The impact response of the sandwiches was investigated using a theoretical approach, based on the energy balance model and the model parameters were obtained by the tomographic analyses of the impacted panels. This combined experimental and theoretical investigation has particular importance for applications that require lightweight composite structures with a high capacity of energy dissipation, such as the transport industry, where problems of collision and crash have increased in the last years.
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Papers by Emre Kara
suitable for applications in the transport industry (automotive, aerospace, shipbuilding industry), where
the “lightweight design” philosophy and the safety of vehicles are very important aspects. The goal of
this paper was the analysis of the bending and the low - velocity impact response of aluminium foam
sandwiches reinforced by the outer skins made of glass fibre reinforced epoxy matrix. The results were
compared with those obtained for aluminium foam sandwiches without glass fibre skins. An analytical
model for the peak load prediction under low velocity impact was developed and the predicted values
are in good agreement with the experimental measurements. The impact response of the sandwiches
was investigated using a theoretical approach, based on the energy balance model and the model parameters
were obtained by the tomographic analyses of the impacted panels.
This combined experimental and theoretical investigation has particular importance for applications
that require lightweight composite structures with a high capacity of energy dissipation, such as the
transport industry, where problems of collision and crash have increased in the last years.
suitable for applications in the transport industry (automotive, aerospace, shipbuilding industry), where
the “lightweight design” philosophy and the safety of vehicles are very important aspects. The goal of
this paper was the analysis of the bending and the low - velocity impact response of aluminium foam
sandwiches reinforced by the outer skins made of glass fibre reinforced epoxy matrix. The results were
compared with those obtained for aluminium foam sandwiches without glass fibre skins. An analytical
model for the peak load prediction under low velocity impact was developed and the predicted values
are in good agreement with the experimental measurements. The impact response of the sandwiches
was investigated using a theoretical approach, based on the energy balance model and the model parameters
were obtained by the tomographic analyses of the impacted panels.
This combined experimental and theoretical investigation has particular importance for applications
that require lightweight composite structures with a high capacity of energy dissipation, such as the
transport industry, where problems of collision and crash have increased in the last years.