A.T. Marques | Faculdade de Engenharia da Universidade do Porto (original) (raw)

Papers by A.T. Marques

Research paper thumbnail of Sustainable Composites Based on Pine Resin and Flax Fibre

In this investigation, we assess the use of pine resin and flax fibre as raw materials for the fo... more In this investigation, we assess the use of pine resin and flax fibre as raw materials for the formulation of a biocomposite material to determine its applicability and demonstrate the hidden potential that may presently be underexploited with these two resources. The formulated biocomposite was subjected to bending tests, comparing reinforced and non-reinforced matrices with flax fibre. Different additives of natural and synthetic origin were used to improve the fragility of the rosin, with EVA (ethylene vinyl acetate) being the material that presented greater potential, in the proportion of 30%. This formulation was used to manufacture innovative products. The results obtained are very promising and opens the opportunity to design and manufacture new sustainable products that can be used in different industrial areas, like furniture and lighting. The products hereby introduced envision to contribute for the rehabilitation of the rosin industry and revive the flax culture in Portugal.

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Research paper thumbnail of Study of the Filament Wound Composite Pipes Damage

Reinforced thermoplastic and thermosetting matrix pipes, produced by filament winding or centrifu... more Reinforced thermoplastic and thermosetting matrix pipes, produced by filament winding or centrifugal casting, may be subjected to different types of loading conditions as well as different environmental conditions. However, they may suffer damage due to unexpected working conditions (low velocity impact, such as stones, tools, etc). This paper describes a methodology based upon fracture mechanics to evaluate possible pipe damages. It reports a set of tests made to characterize materials and pipes. Fracture Mechanics tests were made in filament wound flat samples and tubular specimens were also subjected to low velocity impact tests. The study of damage evolution was done by using the ESPI (Electronic Speckle Pattern Interferometry) technique in order to determine the delamination area.

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Research paper thumbnail of Tool Effects on Hybrid Laminates Drilling

Materials and Manufacturing Processes, 2010

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Research paper thumbnail of Fatigue Behaviour of Reinforced Concrete Beam Strengthened With a CFRP Reinforced System

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Research paper thumbnail of Estudo da Influência da Pré-Furação no Dano em Laminados Carbono/Epóxido

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Research paper thumbnail of Análise Experimental de Tensões em Materiais Compósitos Utilizando sensores de Bragg Embebidos

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Research paper thumbnail of Methodology for Bone–Implant Stiffness Evaluation

Experimental Mechanics

It has been difficult to improve the intramedullary nail technique because of the lack of consist... more It has been difficult to improve the intramedullary nail technique because of the lack of consistency in the procedures used to evaluate the bone-implant stiffness. The goal of this study was to develop a simple methodology for determining the stiffness of a bone implant that considers the physiological loads and bone orientation, and allows a finite element analysis and its validation using mechanical experimentation. Finite element models for a composite tibia before and after an intramedullary nail was implanted were created and validated using the results of a set of mechanical experiments, in which the stiffness values of the model were measured and compared under axial compression, 4-point bending, shear, and torsional loads considering the patient’s condition in the early healing phase. Grips with personalized bone interfaces were developed to guarantee the physiological loads and bone orientation. In the 4-point bending, torsional, and shear loading modes, the developed bone-implant finite element model showed a satisfactory level of predictive potential in relation to the experimental observations, with a percentage variation of less than 35%. This study also demonstrated that despite the high stiffness of the bone-implant construct, motion was always generated at the interfragmentary site during the early healing phase. In addition, during this stage, the nail supported most of the load applied to the lower limb (up to 85%). This strategy could contribute to the future determination of the ideal mechanical environment at a fracture site and how this environment evolves throughout the healing process.

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Research paper thumbnail of Filament Wound Products Made with Thermoplastic Matrix Towpregs

Cost-effective glass-reinforced thermoplastic matrix towpregs produced by a powder coating line w... more Cost-effective glass-reinforced thermoplastic matrix towpregs produced by a powder coating line were used to manufacture composite pipes by filament winding. A conventional 6 axes filament-winding equipment was adapted for processing such structures. The influence of the filament winding speed and mandrel temperature on the composite final properties was studied in the present work. An optimized processing window was established by comparing the composite theoretical expected mechanical properties with the experimentally obtained ones. The final properties determined on the produced pipes and structures and the technological changes introduced to the conventional filament-winding equipment will be presented and discussed. Besides the processing description and conditions, it will be presented the relationship between processing conditions and mechanical properties.

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Research paper thumbnail of Advanced thermoplastic carbon fibre reinforced pultruded composites

The aim of this work is to optimize the production of new continuous carbon fibers reinforced the... more The aim of this work is to optimize the production of new continuous carbon fibers reinforced thermoplastic matrix pre-impregnated materials (towpregs) continuously processed by dry deposition of polymer powders in a new equipment developed by the Institute for Polymers and Composites (IPC). The processing of the produced towpregs by pultrusion, in a developed prototype equipment existing in the Engineering School of the Polytechnic Institute of Porto (ISEP), was also optimized. Two different thermoplastic matrices were studied: one for commercial applications (polypropylene) and another for advanced markets (Primospire®). The optimization was made by studying the influence of the most relevant processing parameters in the final properties of the produced towpregs and composites. The final pultruded composite profiles were submitted to mechanical tests in order to obtain relevant properties.

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Research paper thumbnail of Compression molding of pultruded carbon reinforced thermoplastic composites

Historically, thermoset resins have dominated the composite industry but they start to be replace... more Historically, thermoset resins have dominated the composite industry but they start to be replaced by thermoplastics. In this study two different thermoplastic matrix carbon reinforced pre-impregnated materials were used, one produced in our laboratories (towpreg) and another obtained from coextrusion process (PCT). Carbon fibre and two different thermoplastic matrices (polypropylene and PRIMOSPIRE) were selected for the production of the pre-impregnated materials. Heated compression moulding and pultrusion were the two manufacturing technologies used to obtain composite plates and profiles for study. The optimization of those processes was made by studying the influence of the most relevant processing parameters in the final properties of the produced carbon fibres thermoplastic matrix pre-impregnated materials and composites. The composite relevant mechanical properties were determined and the final composites were submitted to Dynamic Mechanical Analysis (DMA), Scanning Electron ...

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Research paper thumbnail of Comparative Parametric Modelling of Composite Tubes and Composite Overwrapped Pressure Vessels

In this work, the stress and strain levels of composite overwrapped pressure vessels and composit... more In this work, the stress and strain levels of composite overwrapped pressure vessels and composite tube were evaluated, through an accurate numerical modelling based on finite element method (FEM). It was developed the models of the COPV and tubes with three aluminum liner thickness. Initially, the stress and displacement of the composite layers overwrapping the liner was analyzed and graphically represented. The parametric modelling for study the structural relationship between COPV and pipes were made by three new concepts developed in this work, liner stress and liner strain share fraction and thickness ratio. The results showed representative results at lower pressures, e.g. at 70 bar, where a composite tube can parametrically represent a COPV.

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Research paper thumbnail of Processing of continuous fibre reinforced thermoplastics

Towpregs based on different fibres and thermoplastic matrices were processed for highly demanding... more Towpregs based on different fibres and thermoplastic matrices were processed for highly demanding and more commercial applications by different composite processing technologies. In the technologies used, compression moulding and pultrusion, the final composite processing parameters were studied in order to obtain composites with adequate properties at industrial compatible production rates. The produced towpregs were tested to verify its polymer content and degree of impregnation. The obtained results have shown that the coating line enabled to produce, with efficiency and industrial scale speed rates, thermoplastic matrix towpregs that may be used to manufacture composites for advanced and larger volume commercial markets.

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Research paper thumbnail of Flexural Behaviour of GFRP-Polymer Concrete Hybrid Structural Systems

Fibre-Reinforced Polymer Reinforcement for Concrete Structures, 2003

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Research paper thumbnail of Fibrous materials reinforced composites production techniques

Fibrous and Composite Materials for Civil Engineering Applications, 2011

Abstract: This chapter presents the main processing techniques used with organic matrices fibrous... more Abstract: This chapter presents the main processing techniques used with organic matrices fibrous materials reinforced composites, for civil engineering applications. After a brief introduction, followed by the characterization of the main matrices, thermosets and thermoplastics used in these composites, the different techniques applied in various civil engineering applications are presented and discussed: pultrusion, braiding, RTM, filament winding, hot plate press and, finally, hand lay-up.

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Research paper thumbnail of Analyzing objects in images for estimating the delamination influence on load carrying capacity of composite laminates

ELCVIA Electronic Letters on Computer Vision and Image Analysis, 2008

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Research paper thumbnail of Development of Composite Material from Tire Scrapes and Latex for Application in Thermal Insulation

Revista de Engenharia Térmica, 2009

Given the unquestionable need of environmental preservation of discarded industrial residues, the... more Given the unquestionable need of environmental preservation of discarded industrial residues, the scrape of tires, have been seen as a salutary alternative for addictive in concrete, asphalt production and of other composites materials. In this work, grew a composite the base of scrape of tire as reinforcement and latex as matrix, to be used as insulating thermal…

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Research paper thumbnail of Impact of the geometry of inclusions at the micro-scale on the overall stochastic properties

Mechanics of Advanced Materials and Structures, 2015

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Research paper thumbnail of Pultrusion of fibre reinforced thermoplastic pre-impregnated materials

Composites Part B: Engineering, 2016

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Research paper thumbnail of Optimizing the Strengthening and Reinforcement of Concrete Beams by the use of CFRP Filament Winding

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Research paper thumbnail of In-plane mechanical behaviour of a glass/epoxy composite

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Research paper thumbnail of Sustainable Composites Based on Pine Resin and Flax Fibre

In this investigation, we assess the use of pine resin and flax fibre as raw materials for the fo... more In this investigation, we assess the use of pine resin and flax fibre as raw materials for the formulation of a biocomposite material to determine its applicability and demonstrate the hidden potential that may presently be underexploited with these two resources. The formulated biocomposite was subjected to bending tests, comparing reinforced and non-reinforced matrices with flax fibre. Different additives of natural and synthetic origin were used to improve the fragility of the rosin, with EVA (ethylene vinyl acetate) being the material that presented greater potential, in the proportion of 30%. This formulation was used to manufacture innovative products. The results obtained are very promising and opens the opportunity to design and manufacture new sustainable products that can be used in different industrial areas, like furniture and lighting. The products hereby introduced envision to contribute for the rehabilitation of the rosin industry and revive the flax culture in Portugal.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Study of the Filament Wound Composite Pipes Damage

Reinforced thermoplastic and thermosetting matrix pipes, produced by filament winding or centrifu... more Reinforced thermoplastic and thermosetting matrix pipes, produced by filament winding or centrifugal casting, may be subjected to different types of loading conditions as well as different environmental conditions. However, they may suffer damage due to unexpected working conditions (low velocity impact, such as stones, tools, etc). This paper describes a methodology based upon fracture mechanics to evaluate possible pipe damages. It reports a set of tests made to characterize materials and pipes. Fracture Mechanics tests were made in filament wound flat samples and tubular specimens were also subjected to low velocity impact tests. The study of damage evolution was done by using the ESPI (Electronic Speckle Pattern Interferometry) technique in order to determine the delamination area.

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Research paper thumbnail of Tool Effects on Hybrid Laminates Drilling

Materials and Manufacturing Processes, 2010

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Research paper thumbnail of Fatigue Behaviour of Reinforced Concrete Beam Strengthened With a CFRP Reinforced System

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Estudo da Influência da Pré-Furação no Dano em Laminados Carbono/Epóxido

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Análise Experimental de Tensões em Materiais Compósitos Utilizando sensores de Bragg Embebidos

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Methodology for Bone–Implant Stiffness Evaluation

Experimental Mechanics

It has been difficult to improve the intramedullary nail technique because of the lack of consist... more It has been difficult to improve the intramedullary nail technique because of the lack of consistency in the procedures used to evaluate the bone-implant stiffness. The goal of this study was to develop a simple methodology for determining the stiffness of a bone implant that considers the physiological loads and bone orientation, and allows a finite element analysis and its validation using mechanical experimentation. Finite element models for a composite tibia before and after an intramedullary nail was implanted were created and validated using the results of a set of mechanical experiments, in which the stiffness values of the model were measured and compared under axial compression, 4-point bending, shear, and torsional loads considering the patient’s condition in the early healing phase. Grips with personalized bone interfaces were developed to guarantee the physiological loads and bone orientation. In the 4-point bending, torsional, and shear loading modes, the developed bone-implant finite element model showed a satisfactory level of predictive potential in relation to the experimental observations, with a percentage variation of less than 35%. This study also demonstrated that despite the high stiffness of the bone-implant construct, motion was always generated at the interfragmentary site during the early healing phase. In addition, during this stage, the nail supported most of the load applied to the lower limb (up to 85%). This strategy could contribute to the future determination of the ideal mechanical environment at a fracture site and how this environment evolves throughout the healing process.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Filament Wound Products Made with Thermoplastic Matrix Towpregs

Cost-effective glass-reinforced thermoplastic matrix towpregs produced by a powder coating line w... more Cost-effective glass-reinforced thermoplastic matrix towpregs produced by a powder coating line were used to manufacture composite pipes by filament winding. A conventional 6 axes filament-winding equipment was adapted for processing such structures. The influence of the filament winding speed and mandrel temperature on the composite final properties was studied in the present work. An optimized processing window was established by comparing the composite theoretical expected mechanical properties with the experimentally obtained ones. The final properties determined on the produced pipes and structures and the technological changes introduced to the conventional filament-winding equipment will be presented and discussed. Besides the processing description and conditions, it will be presented the relationship between processing conditions and mechanical properties.

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Research paper thumbnail of Advanced thermoplastic carbon fibre reinforced pultruded composites

The aim of this work is to optimize the production of new continuous carbon fibers reinforced the... more The aim of this work is to optimize the production of new continuous carbon fibers reinforced thermoplastic matrix pre-impregnated materials (towpregs) continuously processed by dry deposition of polymer powders in a new equipment developed by the Institute for Polymers and Composites (IPC). The processing of the produced towpregs by pultrusion, in a developed prototype equipment existing in the Engineering School of the Polytechnic Institute of Porto (ISEP), was also optimized. Two different thermoplastic matrices were studied: one for commercial applications (polypropylene) and another for advanced markets (Primospire®). The optimization was made by studying the influence of the most relevant processing parameters in the final properties of the produced towpregs and composites. The final pultruded composite profiles were submitted to mechanical tests in order to obtain relevant properties.

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Research paper thumbnail of Compression molding of pultruded carbon reinforced thermoplastic composites

Historically, thermoset resins have dominated the composite industry but they start to be replace... more Historically, thermoset resins have dominated the composite industry but they start to be replaced by thermoplastics. In this study two different thermoplastic matrix carbon reinforced pre-impregnated materials were used, one produced in our laboratories (towpreg) and another obtained from coextrusion process (PCT). Carbon fibre and two different thermoplastic matrices (polypropylene and PRIMOSPIRE) were selected for the production of the pre-impregnated materials. Heated compression moulding and pultrusion were the two manufacturing technologies used to obtain composite plates and profiles for study. The optimization of those processes was made by studying the influence of the most relevant processing parameters in the final properties of the produced carbon fibres thermoplastic matrix pre-impregnated materials and composites. The composite relevant mechanical properties were determined and the final composites were submitted to Dynamic Mechanical Analysis (DMA), Scanning Electron ...

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Research paper thumbnail of Comparative Parametric Modelling of Composite Tubes and Composite Overwrapped Pressure Vessels

In this work, the stress and strain levels of composite overwrapped pressure vessels and composit... more In this work, the stress and strain levels of composite overwrapped pressure vessels and composite tube were evaluated, through an accurate numerical modelling based on finite element method (FEM). It was developed the models of the COPV and tubes with three aluminum liner thickness. Initially, the stress and displacement of the composite layers overwrapping the liner was analyzed and graphically represented. The parametric modelling for study the structural relationship between COPV and pipes were made by three new concepts developed in this work, liner stress and liner strain share fraction and thickness ratio. The results showed representative results at lower pressures, e.g. at 70 bar, where a composite tube can parametrically represent a COPV.

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Research paper thumbnail of Processing of continuous fibre reinforced thermoplastics

Towpregs based on different fibres and thermoplastic matrices were processed for highly demanding... more Towpregs based on different fibres and thermoplastic matrices were processed for highly demanding and more commercial applications by different composite processing technologies. In the technologies used, compression moulding and pultrusion, the final composite processing parameters were studied in order to obtain composites with adequate properties at industrial compatible production rates. The produced towpregs were tested to verify its polymer content and degree of impregnation. The obtained results have shown that the coating line enabled to produce, with efficiency and industrial scale speed rates, thermoplastic matrix towpregs that may be used to manufacture composites for advanced and larger volume commercial markets.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Flexural Behaviour of GFRP-Polymer Concrete Hybrid Structural Systems

Fibre-Reinforced Polymer Reinforcement for Concrete Structures, 2003

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Fibrous materials reinforced composites production techniques

Fibrous and Composite Materials for Civil Engineering Applications, 2011

Abstract: This chapter presents the main processing techniques used with organic matrices fibrous... more Abstract: This chapter presents the main processing techniques used with organic matrices fibrous materials reinforced composites, for civil engineering applications. After a brief introduction, followed by the characterization of the main matrices, thermosets and thermoplastics used in these composites, the different techniques applied in various civil engineering applications are presented and discussed: pultrusion, braiding, RTM, filament winding, hot plate press and, finally, hand lay-up.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Analyzing objects in images for estimating the delamination influence on load carrying capacity of composite laminates

ELCVIA Electronic Letters on Computer Vision and Image Analysis, 2008

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Research paper thumbnail of Development of Composite Material from Tire Scrapes and Latex for Application in Thermal Insulation

Revista de Engenharia Térmica, 2009

Given the unquestionable need of environmental preservation of discarded industrial residues, the... more Given the unquestionable need of environmental preservation of discarded industrial residues, the scrape of tires, have been seen as a salutary alternative for addictive in concrete, asphalt production and of other composites materials. In this work, grew a composite the base of scrape of tire as reinforcement and latex as matrix, to be used as insulating thermal…

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Research paper thumbnail of Impact of the geometry of inclusions at the micro-scale on the overall stochastic properties

Mechanics of Advanced Materials and Structures, 2015

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Pultrusion of fibre reinforced thermoplastic pre-impregnated materials

Composites Part B: Engineering, 2016

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Optimizing the Strengthening and Reinforcement of Concrete Beams by the use of CFRP Filament Winding

Bookmarks Related papers MentionsView impact

Research paper thumbnail of In-plane mechanical behaviour of a glass/epoxy composite

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Research paper thumbnail of Design for sustainability with composite systems

After a general discussion regarding different approaches towards sustainability with composite s... more After a general discussion regarding different approaches towards sustainability with composite systems, several examples will be presented and discussed with respect to the design criteria for a given application. In fact, from the mechanical characterization of PHA and PLA blends to the use of cork as a core in sandwich construction will aim for a larger incorporation of composite systems from renewable resources in structural applications and mass production.

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