The Experts below are selected from a list of 300 Experts worldwide ranked by ideXlab platform
Alkiviadis S. Paipetis - One of the best experts on this subject based on the ideXlab platform.
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Optimisation and analysis of the Reinforcement Effect of carbon nanotubes in a typical matrix system
Meccanica, 2015Co-Authors: Giorgos Gkikas, Alkiviadis S. PaipetisAbstract:The scope of this work is the analysis of the Reinforcement Effect of carbon nanotubes in typical matrix systems, such as epoxy resins. As is well known, efficient dispersion is critical in achieving adequate Reinforcement. However, dispersion processes are also well known to degrade the nano-phase. Degradation is manifested as reduction in the aspect ratio as the nanotubes de-agglomerate and break at the same time. For the purpose of this study, multi-wall carbon nanotubes (MWCNTs) with typical length of 1 μm and diameter of 10–15 nm were used for manufacturing MWCNTs/epoxy nano-composites. The inclusion content was 0.5 and 1 % w/w respectively, and dispersion was performed using a typical sonicator gun. The tensile and the fracture toughness properties of the specimens were initially assessed and subsequently optimized. The optimisation process resulted in spectacular improvement in toughness properties. Finally, the antagonistic mechanisms that govern the Reinforcement efficient were analysed via the application of the Halpin–Tsai equations for the tensile properties and the distinct contributions of the mechanisms that dissipate energy and enhance toughness, such as the nanotube pull-out, the plastic void growth of the epoxy and the nanotube debonding energy. The de-agglomeration and the aspect ratio reduction were shown to adversely affect the nano-composite properties and create an optimization envelop, well predicted by the employed simple models.
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Optimisation and analysis of the Reinforcement Effect of carbon nanotubes in a typical matrix system
Meccanica, 2014Co-Authors: Giorgos Gkikas, Alkiviadis S. PaipetisAbstract:The scope of this work is the analysis of the Reinforcement Effect of carbon nanotubes in typical matrix systems, such as epoxy resins. As is well known, efficient dispersion is critical in achieving adequate Reinforcement. However, dispersion processes are also well known to degrade the nano-phase. Degradation is manifested as reduction in the aspect ratio as the nanotubes de-agglomerate and break at the same time. For the purpose of this study, multi-wall carbon nanotubes (MWCNTs) with typical length of 1 lm and diameter of 10-15 nm were used for manufactur- ing MWCNTs/epoxy nano-composites. The inclusion content was 0.5 and 1 % w/w respectively, and dispersion was performed using a typical sonicator gun. The tensile and the fracture toughness properties of the specimens were initially assessed and subse- quently optimized. The optimisation process resulted in spectacular improvement in toughness properties. Finally, the antagonistic mechanisms that govern the Reinforcement efficient were analysed via the applica- tion of the Halpin-Tsai equations for the tensile properties and the distinct contributions of the mech- anisms that dissipate energy and enhance toughness, such as the nanotube pull-out, the plastic void growth of the epoxy and the nanotube debonding energy. The de-agglomeration and the aspect ratio reduction were
Giorgos Gkikas - One of the best experts on this subject based on the ideXlab platform.
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Optimisation and analysis of the Reinforcement Effect of carbon nanotubes in a typical matrix system
Meccanica, 2015Co-Authors: Giorgos Gkikas, Alkiviadis S. PaipetisAbstract:The scope of this work is the analysis of the Reinforcement Effect of carbon nanotubes in typical matrix systems, such as epoxy resins. As is well known, efficient dispersion is critical in achieving adequate Reinforcement. However, dispersion processes are also well known to degrade the nano-phase. Degradation is manifested as reduction in the aspect ratio as the nanotubes de-agglomerate and break at the same time. For the purpose of this study, multi-wall carbon nanotubes (MWCNTs) with typical length of 1 μm and diameter of 10–15 nm were used for manufacturing MWCNTs/epoxy nano-composites. The inclusion content was 0.5 and 1 % w/w respectively, and dispersion was performed using a typical sonicator gun. The tensile and the fracture toughness properties of the specimens were initially assessed and subsequently optimized. The optimisation process resulted in spectacular improvement in toughness properties. Finally, the antagonistic mechanisms that govern the Reinforcement efficient were analysed via the application of the Halpin–Tsai equations for the tensile properties and the distinct contributions of the mechanisms that dissipate energy and enhance toughness, such as the nanotube pull-out, the plastic void growth of the epoxy and the nanotube debonding energy. The de-agglomeration and the aspect ratio reduction were shown to adversely affect the nano-composite properties and create an optimization envelop, well predicted by the employed simple models.
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Optimisation and analysis of the Reinforcement Effect of carbon nanotubes in a typical matrix system
Meccanica, 2014Co-Authors: Giorgos Gkikas, Alkiviadis S. PaipetisAbstract:The scope of this work is the analysis of the Reinforcement Effect of carbon nanotubes in typical matrix systems, such as epoxy resins. As is well known, efficient dispersion is critical in achieving adequate Reinforcement. However, dispersion processes are also well known to degrade the nano-phase. Degradation is manifested as reduction in the aspect ratio as the nanotubes de-agglomerate and break at the same time. For the purpose of this study, multi-wall carbon nanotubes (MWCNTs) with typical length of 1 lm and diameter of 10-15 nm were used for manufactur- ing MWCNTs/epoxy nano-composites. The inclusion content was 0.5 and 1 % w/w respectively, and dispersion was performed using a typical sonicator gun. The tensile and the fracture toughness properties of the specimens were initially assessed and subse- quently optimized. The optimisation process resulted in spectacular improvement in toughness properties. Finally, the antagonistic mechanisms that govern the Reinforcement efficient were analysed via the applica- tion of the Halpin-Tsai equations for the tensile properties and the distinct contributions of the mech- anisms that dissipate energy and enhance toughness, such as the nanotube pull-out, the plastic void growth of the epoxy and the nanotube debonding energy. The de-agglomeration and the aspect ratio reduction were
Bernardo Zuccarello - One of the best experts on this subject based on the ideXlab platform.
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The Reinforcement Effect of Strain Gauges Embedded in Low Modulus Materials
Strain, 2013Co-Authors: Augusto Ajovalasit, Salvatore Fragapane, Bernardo ZuccarelloAbstract:The Reinforcement Effect of electrical resistance strain gauges is well-described in the literature, especially for strain gauges installed on surface. This paper considers the local Reinforcement Effect of strain gauges embedded within low Young modulus materials. In particular, by using a simple theoretical model, already used for strain gauges installed on the surface, it proposes a simple formula that allows the user to evaluate the local Reinforcement Effect of a generic strain gauge embedded on plastics, polymer composites, etc. The theoretical analysis has been integrated by numerical and experimental analyses, which confirmed the reliability of the proposed model.
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Local Reinforcement Effect of embedded strain gauges
EPJ Web of Conferences, 2010Co-Authors: Augusto Ajovalasit, Salvatore Fragapane, Bernardo ZuccarelloAbstract:The Reinforcement Effect of strain gauges installed on low Young's modulus materials has received attention by many researchers with respect to both strain gauges installed on the surface [1,2] and embedded inside the material [3,4]. In the case of strain gauges installed on the surface, the evaluation of the local Reinforcement Effect gives [5] the following correction coefficient C, i.e. the ratio between the actual strain (without the strain gauge) and the strain ' measured by the strain gauge:
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Stiffness and Reinforcement Effect of Electrical Resistance Strain Gauges
Strain, 2007Co-Authors: Augusto Ajovalasit, Leonardo D'acquisto, Salvatore Fragapane, Bernardo ZuccarelloAbstract:: The increasing use of low-modulus materials, on which the Reinforcement Effect of the electrical resistance strain gauge is not negligible, has re-opened the research interest into this issue. This study deals with the evaluation of stiffness, and of the strain gauge Young's modulus involved in the estimation of both the global and the local Reinforcement Effect; the relationship between the strain gauge stiffness and the local Reinforcement Effect is also analysed. In particular, the experimental technique used to determine the stiffness of some commercial strain gauges is described. The results show that the strain gauge stiffness alone does not permit an accurate evaluation of the local Reinforcement Effect.
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ON THE STIFFNESS AND THE Reinforcement Effect OF ELECTRICAL RESISTANCE STRAIN GAUGES
Applied Mechanics and Materials, 2006Co-Authors: Augusto Ajovalasit, Leonardo D'acquisto, Salvatore Fragapane, Bernardo ZuccarelloAbstract:The Reinforcement Effect of a strain gauge installed on low modulus materials can be significant. The increasing use of low modulus materials requires therefore the evaluation of such Effect. This paper concerns the relationship between the local Reinforcement Effect and the strain gauge stiffness. The conclusion is that the gauge stiffness alone does not allow the user a thorough evaluation of the Reinforcement Effect.
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local Reinforcement Effect of a strain gauge installation on low modulus materials
Journal of Strain Analysis for Engineering Design, 2005Co-Authors: Augusto Ajovalasit, Bernardo ZuccarelloAbstract:The Reinforcement Effect of electrical resistance strain gauges is well documented in the technical literature. In this paper the local Reinforcement Effect in tension is studied by using a simple theoretical model by considering a strain gauge mounted on a semi-infinite plate having the same width of the strain gauge and subjected to a uniaxial tension load. Neglecting the Effect of the adhesive layer and considering the interface shear stress as an exponential distribution, the proposed model gives a closed-form solution. In detail, this model permits a simple formula to be obtained which allows the user to correct the local Reinforcement Effect provided that a proper calibration is performed by installing a strain gauge, of the same type as that used on the structure, on a low modulus material. Experimental evidence of the proposed method is shown. Experimental proof of the positive Effect of large grid lengths on the local Reinforcement Effect is also reported.
Augusto Ajovalasit - One of the best experts on this subject based on the ideXlab platform.
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The Reinforcement Effect of Strain Gauges Embedded in Low Modulus Materials
Strain, 2013Co-Authors: Augusto Ajovalasit, Salvatore Fragapane, Bernardo ZuccarelloAbstract:The Reinforcement Effect of electrical resistance strain gauges is well-described in the literature, especially for strain gauges installed on surface. This paper considers the local Reinforcement Effect of strain gauges embedded within low Young modulus materials. In particular, by using a simple theoretical model, already used for strain gauges installed on the surface, it proposes a simple formula that allows the user to evaluate the local Reinforcement Effect of a generic strain gauge embedded on plastics, polymer composites, etc. The theoretical analysis has been integrated by numerical and experimental analyses, which confirmed the reliability of the proposed model.
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Local Reinforcement Effect of embedded strain gauges
EPJ Web of Conferences, 2010Co-Authors: Augusto Ajovalasit, Salvatore Fragapane, Bernardo ZuccarelloAbstract:The Reinforcement Effect of strain gauges installed on low Young's modulus materials has received attention by many researchers with respect to both strain gauges installed on the surface [1,2] and embedded inside the material [3,4]. In the case of strain gauges installed on the surface, the evaluation of the local Reinforcement Effect gives [5] the following correction coefficient C, i.e. the ratio between the actual strain (without the strain gauge) and the strain ' measured by the strain gauge:
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Stiffness and Reinforcement Effect of Electrical Resistance Strain Gauges
Strain, 2007Co-Authors: Augusto Ajovalasit, Leonardo D'acquisto, Salvatore Fragapane, Bernardo ZuccarelloAbstract:: The increasing use of low-modulus materials, on which the Reinforcement Effect of the electrical resistance strain gauge is not negligible, has re-opened the research interest into this issue. This study deals with the evaluation of stiffness, and of the strain gauge Young's modulus involved in the estimation of both the global and the local Reinforcement Effect; the relationship between the strain gauge stiffness and the local Reinforcement Effect is also analysed. In particular, the experimental technique used to determine the stiffness of some commercial strain gauges is described. The results show that the strain gauge stiffness alone does not permit an accurate evaluation of the local Reinforcement Effect.
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ON THE STIFFNESS AND THE Reinforcement Effect OF ELECTRICAL RESISTANCE STRAIN GAUGES
Applied Mechanics and Materials, 2006Co-Authors: Augusto Ajovalasit, Leonardo D'acquisto, Salvatore Fragapane, Bernardo ZuccarelloAbstract:The Reinforcement Effect of a strain gauge installed on low modulus materials can be significant. The increasing use of low modulus materials requires therefore the evaluation of such Effect. This paper concerns the relationship between the local Reinforcement Effect and the strain gauge stiffness. The conclusion is that the gauge stiffness alone does not allow the user a thorough evaluation of the Reinforcement Effect.
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local Reinforcement Effect of a strain gauge installation on low modulus materials
Journal of Strain Analysis for Engineering Design, 2005Co-Authors: Augusto Ajovalasit, Bernardo ZuccarelloAbstract:The Reinforcement Effect of electrical resistance strain gauges is well documented in the technical literature. In this paper the local Reinforcement Effect in tension is studied by using a simple theoretical model by considering a strain gauge mounted on a semi-infinite plate having the same width of the strain gauge and subjected to a uniaxial tension load. Neglecting the Effect of the adhesive layer and considering the interface shear stress as an exponential distribution, the proposed model gives a closed-form solution. In detail, this model permits a simple formula to be obtained which allows the user to correct the local Reinforcement Effect provided that a proper calibration is performed by installing a strain gauge, of the same type as that used on the structure, on a low modulus material. Experimental evidence of the proposed method is shown. Experimental proof of the positive Effect of large grid lengths on the local Reinforcement Effect is also reported.
Fengwei Xie - One of the best experts on this subject based on the ideXlab platform.
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Starch-zinc complex and its Reinforcement Effect on starch-based materials.
Carbohydrate polymers, 2018Co-Authors: Peng Liu, Li Ying, Xiaoqin Shang, Fengwei XieAbstract:In this work, we found that ZnCl2 solution can not only be used as a plasticizer for starch but also provide a mechanical Reinforcement Effect to the resultant starch-based materials. By a one-step compression molding process, well-plasticized starch-based films could be obtained at 120 °C with a 15 wt.% ZnCl2 solution. Both the tensile strength and elongation at break of the films increased with a rise in ZnCl2 concentration, which demonstrates a mechanical Reinforcement. This Reinforcement could be mainly ascribed to the in-situ formed starch-zinc complexes and the enhanced starch molecular interactions. Moreover, if the processing method was changed into firstly mixing followed by compression molding, the tensile strength increased by more than three folds at no cost of the elongation at break. Regarding this, we propose that shear could further enhance the molecular interactions within the material. However, if the ZnCl2 concentration was too high, the mechanical properties were then reduced irrespective of the processing protocol, which could be due to the weakened molecular interactions by ZnCl2. Thus, we have demonstrated a new, simple method for preparing starch-based composite materials with enhanced mechanical properties, which could be potentially applied to many fields such as packaging, coating and biomedical materials.
