The Experts below are selected from a list of 201 Experts worldwide ranked by ideXlab platform
Valter Carvelli - One of the best experts on this subject based on the ideXlab platform.
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long term bending performance and service life prediction of pultruded glass fibre reinforced polymer composites
Composite Structures, 2015Co-Authors: Guglielmo Carra, Valter CarvelliAbstract:Abstract This paper presents an experimental investigation on the long-term mechanical performance, focusing on bending, of pultruded composite plates adopted as cladding in building constructions. Three matrices have been used in combination with E-glass fibres: isophthalic Polyester, Orthophthalic Polyester and vinylester. The degradation of the mechanical performance has been monitored through a process of accelerated artificial ageing by using water baths set at different temperatures: 20 °C, 40 °C and 60 °C. Flexural strength retention through time has been used as measurement of the imparted degradation and water absorption has been considered to define the diffusion coefficient and the activation energy for the three compositions. The Arrhenius methodology has been adopted to estimate the long-term degradation of the composites and to predict the expected service life of the materials. The outputs of the research show that isophthalic and vinylester systems have flexural strength retention of 65% for more than 75 and 100 years, respectively, while the Orthophthalic composite has the same retention for more than 20 years.
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Long-term bending performance and service life prediction of pultruded Glass Fibre Reinforced Polymer composites
Composite Structures, 2015Co-Authors: Guglielmo Carra, Valter CarvelliAbstract:Abstract This paper presents an experimental investigation on the long-term mechanical performance, focusing on bending, of pultruded composite plates adopted as cladding in building constructions. Three matrices have been used in combination with E-glass fibres: isophthalic Polyester, Orthophthalic Polyester and vinylester. The degradation of the mechanical performance has been monitored through a process of accelerated artificial ageing by using water baths set at different temperatures: 20 °C, 40 °C and 60 °C. Flexural strength retention through time has been used as measurement of the imparted degradation and water absorption has been considered to define the diffusion coefficient and the activation energy for the three compositions. The Arrhenius methodology has been adopted to estimate the long-term degradation of the composites and to predict the expected service life of the materials. The outputs of the research show that isophthalic and vinylester systems have flexural strength retention of 65% for more than 75 and 100 years, respectively, while the Orthophthalic composite has the same retention for more than 20 years.
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ageing of pultruded glass fibre reinforced polymer composites exposed to combined environmental agents
Composite Structures, 2014Co-Authors: Guglielmo Carra, Valter CarvelliAbstract:Abstract This paper presents an experimental research on the durability of pultruded Glass Fibre Reinforced Polymer (GFRP) composites applied in building construction. Three different matrices have been used with E-glass fibres: isophthalic Polyester, Orthophthalic Polyester and vinylester. The degradation of the mechanical and aesthetical performance of the composites has been monitored through a process of accelerated artificial ageing in a climatic chamber, simulating the combined effect of high temperature, freeze–thaw cycles, moisture and ultraviolet (UV) radiation. Tensile, bending and interlinear shear strength tests have been performed to measure the variation of some mechanical properties during six months of artificial exposition. A consistent reduction of the mechanical performance has been observed. Aesthetical appearance has been affected as well both in terms of loss of lightness and colour variation. The data collected have been compared to those after one year of natural ageing in external atmosphere. It has been observed that the considered artificial ageing produces a higher degradation of some mechanical properties if compared to the natural ageing in north Italy climate, accelerating the effects of the environment.
Guglielmo Carra - One of the best experts on this subject based on the ideXlab platform.
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long term bending performance and service life prediction of pultruded glass fibre reinforced polymer composites
Composite Structures, 2015Co-Authors: Guglielmo Carra, Valter CarvelliAbstract:Abstract This paper presents an experimental investigation on the long-term mechanical performance, focusing on bending, of pultruded composite plates adopted as cladding in building constructions. Three matrices have been used in combination with E-glass fibres: isophthalic Polyester, Orthophthalic Polyester and vinylester. The degradation of the mechanical performance has been monitored through a process of accelerated artificial ageing by using water baths set at different temperatures: 20 °C, 40 °C and 60 °C. Flexural strength retention through time has been used as measurement of the imparted degradation and water absorption has been considered to define the diffusion coefficient and the activation energy for the three compositions. The Arrhenius methodology has been adopted to estimate the long-term degradation of the composites and to predict the expected service life of the materials. The outputs of the research show that isophthalic and vinylester systems have flexural strength retention of 65% for more than 75 and 100 years, respectively, while the Orthophthalic composite has the same retention for more than 20 years.
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Long-term bending performance and service life prediction of pultruded Glass Fibre Reinforced Polymer composites
Composite Structures, 2015Co-Authors: Guglielmo Carra, Valter CarvelliAbstract:Abstract This paper presents an experimental investigation on the long-term mechanical performance, focusing on bending, of pultruded composite plates adopted as cladding in building constructions. Three matrices have been used in combination with E-glass fibres: isophthalic Polyester, Orthophthalic Polyester and vinylester. The degradation of the mechanical performance has been monitored through a process of accelerated artificial ageing by using water baths set at different temperatures: 20 °C, 40 °C and 60 °C. Flexural strength retention through time has been used as measurement of the imparted degradation and water absorption has been considered to define the diffusion coefficient and the activation energy for the three compositions. The Arrhenius methodology has been adopted to estimate the long-term degradation of the composites and to predict the expected service life of the materials. The outputs of the research show that isophthalic and vinylester systems have flexural strength retention of 65% for more than 75 and 100 years, respectively, while the Orthophthalic composite has the same retention for more than 20 years.
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ageing of pultruded glass fibre reinforced polymer composites exposed to combined environmental agents
Composite Structures, 2014Co-Authors: Guglielmo Carra, Valter CarvelliAbstract:Abstract This paper presents an experimental research on the durability of pultruded Glass Fibre Reinforced Polymer (GFRP) composites applied in building construction. Three different matrices have been used with E-glass fibres: isophthalic Polyester, Orthophthalic Polyester and vinylester. The degradation of the mechanical and aesthetical performance of the composites has been monitored through a process of accelerated artificial ageing in a climatic chamber, simulating the combined effect of high temperature, freeze–thaw cycles, moisture and ultraviolet (UV) radiation. Tensile, bending and interlinear shear strength tests have been performed to measure the variation of some mechanical properties during six months of artificial exposition. A consistent reduction of the mechanical performance has been observed. Aesthetical appearance has been affected as well both in terms of loss of lightness and colour variation. The data collected have been compared to those after one year of natural ageing in external atmosphere. It has been observed that the considered artificial ageing produces a higher degradation of some mechanical properties if compared to the natural ageing in north Italy climate, accelerating the effects of the environment.
Eve Maria Freire De Aquino - One of the best experts on this subject based on the ideXlab platform.
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Mechanical behavior and water absorption in sisal/glass hybrid composites
Matéria (Rio de Janeiro), 2018Co-Authors: Camila Cruz Da Silva, Raimundo Carlos Silverio Freire Júnior, Elmo Thiago Lins Cöuras Ford, Jayna Kátia Dionisio Dos Santos, Camilla De Medeiros Dantas, Eve Maria Freire De AquinoAbstract:This study aimed to assess the effect of hybridization on thermomechanical properties and water absorption of composite materials, by introducing sisal fiber tissue into the material. To that end, two composite material plates were manufactured, the first with five layers of E-glass reinforcement mat and the second with three layers of E-glass fiber interspersed with two layers of sisal fibers, both used as an Orthophthalic Polyester resin matrix. The material was then submitted to tensile, three-point bending and water absorption tests. It was observed that hybridization causes a change in both the final strength and stiffness of the material. Keywords: Composite material, water absorption, mechanical properties, natural fibers.
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Mechanical behavior and water absorption in sisal/glass hybrid composites
2018Co-Authors: Camila Cruz Da Silva, Raimundo Carlos Silverio Freire Júnior, Elmo Thiago Lins Cöuras Ford, Camilla Medeiros Dantas, Jayna Kátia Dionisio Dos Santos, Eve Maria Freire De AquinoAbstract:ABSTRACT This study aimed to assess the effect of hybridization on thermomechanical properties and water absorption of composite materials, by introducing sisal fiber tissue into the material. To that end, two composite material plates were manufactured, the first with five layers of E-glass reinforcement mat and the second with three layers of E-glass fiber interspersed with two layers of sisal fibers, both used as an Orthophthalic Polyester resin matrix. The material was then submitted to tensile, three-point bending and water absorption tests. It was observed that hybridization causes a change in both the final strength and stiffness of the material.
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Bending in laminas of NFPR: type of reinforcement, fracture and properties
Materials Research, 2011Co-Authors: Mirtânia Antunes Leão, Sérgio Renan Lopes Tinô, Raphael Siqueira Fontes, Eve Maria Freire De AquinoAbstract:Natural fiber reinforced plastics (NFRP) have awakened considerable interest in the area of polymer composites, because of the need to develop new, environmentally friendly materials. One of the most complex ways of manufacturing this type of material is in the form of ultrathin laminar layers; however, this process hinders mechanical testing, mainly three and four-point bending. The present investigation faces this challenge and shows the influence of parameters, such as the grammage of reinforcing fabric and lamination process, on strength, stiffness and fracture characteristics for three-point bending in this type of structural element. The industrially manufactured laminas were composed of Orthophthalic Polyester resin reinforced with licuri fibers. Macromechanical and micromechanical analyses were conducted in the study of fracture characteristics for all the parameters. The mechanical behavior in the three-point bending of the laminar composite showed that the use of licuri fiber to obtain natural fiber-based plastic is completely viable.
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Comparative study between ANN models and conventional equations in the analysis of fatigue failure of GFRP
International Journal of Fatigue, 2009Co-Authors: Raimundo Carlos Silverio Freire Júnior, Adrião Duarte Dória Neto, Eve Maria Freire De AquinoAbstract:Abstract The purpose of this paper is to assess the applicability of two artificial neural networks (ANN) architecture, perceptron ANN, modular ANN, and Adam’s equation in the modeling of fatigue failure in polymer composites, more specifically in glass fiber reinforced plastic (GFRP). In the application of the model using ANN we show the feasibility of obtaining good results with a small number of S–N curves. The other model used involves applying empirical equations known as Adam’s equations. A comparative study on the application of the aforementioned models is developed based on statistical tools such as correlation coefficient and mean square error. For this analysis we used composite materials in the form of laminar structures with distinct stacking sequences, which are applied industrially in the construction of large reservoirs. Reinforcements consist of mats and bidirectional textile fabric made of E-glass fibers soaked in unsaturated Orthophthalic Polyester resin. These were tested for six different stress ratios: R = 1.43, 10, −1.57, −1, 0.1, and 0.7. The results showed that although ANN modeling is in the initial phase, it has great application potential.
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Curaua/Glass Hybrid Composite: The Effect of Water Aging on the Mechanical Properties:
Journal of Reinforced Plastics and Composites, 2008Co-Authors: R. V. Silva, Eve Maria Freire De Aquino, L.p.s. Rodrigues, A.r.f. BarrosAbstract:A hybrid composite associating natural fibers (curaua) and synthetic fibers (E-glass) was developed and investigated. The hybrid is destined for engineering applications as an alternative material to glass fiber composites, mainly in high moisture environments. Thus, an investigation was conducted to evaluate the degradation of the mechanical properties due to water absorption. The hybrid composite is formed of an Orthophthalic Polyester resin reinforced by layers of glass mats and continuous curaua fibers. Absorption tests were carried out and obtained the composite saturation curve for both distilled water and sea water conditions. A non-hybrid composite (just with curaua fiber), was also evaluated for comparison. The mechanical properties were evaluated through tensile and three-point-bend tests. After the mechanical tests, a fracture characteristics analysis of the tested specimens was carried out.
Raimundo Carlos Silverio Freire Júnior - One of the best experts on this subject based on the ideXlab platform.
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Mechanical behavior and water absorption in sisal/glass hybrid composites
Matéria (Rio de Janeiro), 2018Co-Authors: Camila Cruz Da Silva, Raimundo Carlos Silverio Freire Júnior, Elmo Thiago Lins Cöuras Ford, Jayna Kátia Dionisio Dos Santos, Camilla De Medeiros Dantas, Eve Maria Freire De AquinoAbstract:This study aimed to assess the effect of hybridization on thermomechanical properties and water absorption of composite materials, by introducing sisal fiber tissue into the material. To that end, two composite material plates were manufactured, the first with five layers of E-glass reinforcement mat and the second with three layers of E-glass fiber interspersed with two layers of sisal fibers, both used as an Orthophthalic Polyester resin matrix. The material was then submitted to tensile, three-point bending and water absorption tests. It was observed that hybridization causes a change in both the final strength and stiffness of the material. Keywords: Composite material, water absorption, mechanical properties, natural fibers.
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Mechanical behavior and water absorption in sisal/glass hybrid composites
2018Co-Authors: Camila Cruz Da Silva, Raimundo Carlos Silverio Freire Júnior, Elmo Thiago Lins Cöuras Ford, Camilla Medeiros Dantas, Jayna Kátia Dionisio Dos Santos, Eve Maria Freire De AquinoAbstract:ABSTRACT This study aimed to assess the effect of hybridization on thermomechanical properties and water absorption of composite materials, by introducing sisal fiber tissue into the material. To that end, two composite material plates were manufactured, the first with five layers of E-glass reinforcement mat and the second with three layers of E-glass fiber interspersed with two layers of sisal fibers, both used as an Orthophthalic Polyester resin matrix. The material was then submitted to tensile, three-point bending and water absorption tests. It was observed that hybridization causes a change in both the final strength and stiffness of the material.
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Comparative study between ANN models and conventional equations in the analysis of fatigue failure of GFRP
International Journal of Fatigue, 2009Co-Authors: Raimundo Carlos Silverio Freire Júnior, Adrião Duarte Dória Neto, Eve Maria Freire De AquinoAbstract:Abstract The purpose of this paper is to assess the applicability of two artificial neural networks (ANN) architecture, perceptron ANN, modular ANN, and Adam’s equation in the modeling of fatigue failure in polymer composites, more specifically in glass fiber reinforced plastic (GFRP). In the application of the model using ANN we show the feasibility of obtaining good results with a small number of S–N curves. The other model used involves applying empirical equations known as Adam’s equations. A comparative study on the application of the aforementioned models is developed based on statistical tools such as correlation coefficient and mean square error. For this analysis we used composite materials in the form of laminar structures with distinct stacking sequences, which are applied industrially in the construction of large reservoirs. Reinforcements consist of mats and bidirectional textile fabric made of E-glass fibers soaked in unsaturated Orthophthalic Polyester resin. These were tested for six different stress ratios: R = 1.43, 10, −1.57, −1, 0.1, and 0.7. The results showed that although ANN modeling is in the initial phase, it has great application potential.
P. Casari - One of the best experts on this subject based on the ideXlab platform.
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sea water aging of glass reinforced composites shear behaviour and damage modelling
Journal of Composite Materials, 2001Co-Authors: Peter Davies, F. Mazéas, P. CasariAbstract:This paper presents results from a study of the wet aging of four thermoset resins and their [0°/90°] stitched glass fibre reinforced composites. The matrix resins are Orthophthalic Polyester, isophthalic Polyester, vinyl ester and epoxy. Resins and composites were aged for 18 months, under three immersion conditions: 20°C sea water, 50°C sea water and 50°C distilled water. Tensile tests, on resins and at 45° to fibre direction of composites, both before and after aging enable the influence of matrix resin and aging medium on weight changes and matrix dominated property degradation to be evaluated. This has enabled a unique dataset to be obtained. Alarge part of the shear property loss after aging is recovered after drying. An original application of damage mechanics parameters is used to quantify the changes in composite shear behaviour, in order to provide a more complete representation of the inelastic response.
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Sea Water Aging ofGlass Reinforced Composites:Shear Behaviour andDamage Modelling
Journal of Composite Materials, 2001Co-Authors: Peter Davies, F. Mazéas, P. CasariAbstract:This paper presents results from a study of the wet aging of four thermoset resins and their [0°/90°] stitched glass fibre reinforced composites. The matrix resins are Orthophthalic Polyester, isophthalic Polyester, vinyl ester and epoxy. Resins and composites were aged for 18 months, under three immersion conditions: 20°C sea water, 50°C sea water and 50°C distilled water. Tensile tests,on resins and at 45° to fibre direction of composites, both before and after aging enable the influence of matrix resin and aging medium on weight changes and matrix dominated property degradation to be evaluated. This has enabled a unique data set to be obtained. A large part of the shear property loss after aging is recovered after drying. An original application of damage mechanics parameters is used to quantify the changes in composite shear behaviour, in order to provide a more complete representation of the inelastic response.
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2Laboratoire de Génie Civil de Nantes Saint Nazaire, Faculté des Sciences et des Techniques de Nantes,
2000Co-Authors: Shear Behaviour, F. Mazéas, P. Davies, Damage Modelling, P. CasariAbstract:ABSTRACT: This paper presents results from a study of the wet aging of four thermoset resins and their [0°/90°] stitched glass fibre reinforced composites. The matrix resins are Orthophthalic Polyester, isophthalic Polyester, vinyl ester and epoxy. Resins and compos-ites were aged for 18 months, under three immersion conditions: 20°C sea water, 50°C sea water and 50°C distilled water. Tensile tests, on resins and at 45 ° to fibre direction of com-posites, both before and after aging enable the influence of matrix resin and aging medium on weight changes and matrix dominated property degradation to be evaluated. This has enabled a unique dataset to be obtained. A large part of the shear property loss after aging is recovered after drying. An original application of damage mechanics parameters is used to quantify the changes in composite shear behaviour, in order to provide a more complete representation of the inelastic response
