Alberto Pertuz - Academia.edu (original) (raw)

Papers by Alberto Pertuz

Research paper thumbnail of Impact Strength for 3D-Printed PA6 Polymer Composites under Temperature Changes

Journal of Manufacturing and Materials Processing

This paper shows how temperature influences impact energy for continuous fiber additively manufac... more This paper shows how temperature influences impact energy for continuous fiber additively manufactured (AM) polymer matrix composites. AM composites were fabricated with a nylon-based matrix and four continuous reinforcements: fiberglass, high-temperature fiberglass (HSHT), Kevlar, and carbon. The tested temperatures ranged from −40 to 90 °C. The chosen printed configuration for the lattice structure and fiber volume was the configuration that was found to perform the best in the literature, with a volumetric fiber content of 24.2%. Impact tests showed that the best response was fiberglass, HSHT, Kevlar, and carbon, in that order. The impact resistance was lowered at temperatures below ambient temperatures and above 50 °C. Additionally, each material’s impact energy was adjusted to third-degree polynomials to model results, with correlation factors above 92%. Finally, the failure analysis showed the damage mechanisms of matrix cracking, delamination in the printing direction, fiber ...

Research paper thumbnail of Impact Strength for 3D-Printed PA6 Polymer Composites under Temperature Changes

Manufacturing and Materials Processing, 2023

Abstract: This paper showshowtemperatureinfluencesimpactenergyforcontinuousfiberadditively manufa... more Abstract: This paper showshowtemperatureinfluencesimpactenergyforcontinuousfiberadditively manufactured (AM) polymer matrix composites. AM composites were fabricated with a nylon-based matrix and four continuous reinforcements: fiberglass, high-temperature fiberglass (HSHT), Kevlar, and carbon. The tested temperatures ranged from −40 to 90 ◦C. The chosen printed configuration for the lattice structure and fiber volume was the configuration that was found to perform the best in the literature, with a volumetric fiber content of 24.2%. Impact tests showed that the best response was fiberglass, HSHT, Kevlar, and carbon, in that order. The impact resistance was lowered at temperatures below ambient temperatures and above 50 ◦C. Additionally, each material’s impact energy was adjusted to third-degree polynomials to model results, with correlation factors above 92%. Finally, the failure analysis showed the damage mechanisms of matrix cracking, delamination in the printing direction, fiber tearing, and fiber pulling as failure mechanisms.

Research paper thumbnail of Impact Strength for 3D-Printed PA6 Polymer Composites under Temperature Changes

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Impact Strength for 3D-Printed PA6 Polymer Composites under Temperature Changes

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Cement system design used in anchorage wells for offshore deepwater production platforms: Event: Rio de Janeiro, Brasil

Revista de la Facultad de Ingeniería Universidad Central de Venezuela, Mar 1, 2013

Research paper thumbnail of Composite pipe: State of the art, stress analysis and first ply failure

HAL (Le Centre pour la Communication Scientifique Directe), Oct 17, 2016

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Distributed under a Creative Commons Attribution-NoDerivatives| 4.0 International License

Research paper thumbnail of Damage evolution in composite pipes using a continuum damage mechanics formulation

HAL (Le Centre pour la Communication Scientifique Directe), Jun 14, 2017

Composite pipes are replacing conventional steel pipes in oil and gas transport applications. The... more Composite pipes are replacing conventional steel pipes in oil and gas transport applications. Their strength is determined by specific failure criteria for composite materials, however, once the damage has initiated there exists an interest in knowing how it propagates or evolves in order to determine the remaining life of a pipe. After damage initiation, mechanisms like micro cracking, fiber rupture, fiber-matrix debonding and delamination can occur [1]. Continuum damage mechanics is a phenomenological theory for taking into account these mechanisms in the effects of the mechanical material behavior [2]. Currently, it exists a variety of damage models for composites laminates [3]. Ferry et al. [4] have proposed an anisotropic damage model for pipes with good agreement with experimental data. Other models are also developed or implemented for composite pipes for example in [5]. Solution of these models are indeed not very easy and usually an implementation in a FEA (Finite Element Analysis) code is needed. A common numerical method to solve for these equations is the return mapping algorithm. In this work, we study the numerical methods available for the solution of damage evolution in composite laminates by the application of an industrial example: composite pipes.

Research paper thumbnail of A new model to determine the hardness of thin films

HAL (Le Centre pour la Communication Scientifique Directe), 2004

Research paper thumbnail of Methods for treating damage in composite materials, an application to pipes

HAL (Le Centre pour la Communication Scientifique Directe), Aug 16, 2017

Research paper thumbnail of Stress analysis, first ply failure and damage of a multilayer composite pipe for different boundary conditions

HAL (Le Centre pour la Communication Scientifique Directe), May 25, 2017

Research paper thumbnail of Mechanical behavior analysis of a vertical axis wind turbine blade made with fique-epoxy composite using FEM

Procedia Computer Science

Research paper thumbnail of Damage in Fibreglass Composite Laminates Used for Pipes

Key Engineering Materials, 2018

In this work, we present a model for the initiation and evolution of damage for a composite fibre... more In this work, we present a model for the initiation and evolution of damage for a composite fibre-reinforced pipe used in the Oil & Gas industry, based on a commercially available pipe. A continuum damage mechanics model was employed to determine the initiation and evolution of damage. This model was implemented using finite element analysis to investigate the performance of the commercial composite pipe. Initially, the material properties were obtained from experimental data and fitting with static structural simulations. Then, FE simulations with damage were performed, considering three different boundary conditions: open, closed (pressure-vessel type) and fixed ends, the load considered was internal pressure. Results showed differences not only in the stress distribution but on the damage initiation and evolution along the geometry of the pipe. These differences in the damage initiation and propagation can be explained as the result of different axial-hoop stress ratio.

Research paper thumbnail of A model for hardness determination of thin coatings from standard micro-indentation tests

Surface and Coatings Technology, 2005

Determination of surface hardness of thin films using standard micro-indentation testers has to a... more Determination of surface hardness of thin films using standard micro-indentation testers has to address the problem of the range of indentation loads available with these testers. In fact, they are often too high to allow the direct determination of the film hardness without involving a contribution of the substrate. As a consequence, the calculated hardness value is not the hardness of the film but an apparent surface hardness. Since this “composite” hardness is the result of two contributions, models are necessary to separate them in order to determine the true film hardness. The application of such models may however require the introduction of coefficients or data or involve some other adjustment method. In order to avoid the need for such other data parameter, we propose a new model, which gives predictions in good accordance with the average ones of the other models.

Research paper thumbnail of Fatigue in Continuous Fibre Reinforced Thermoplastic Composites

Additive manufacturing (AM) technologies have been applied with success in many applications, bei... more Additive manufacturing (AM) technologies have been applied with success in many applications, being fused deposition modelling (FDM) the most widely used AM technique for fabricating thermoplastic pieces. The thermoplastic parts made by FDM present lack of strength and low stiffness, as required for fully functional and load-bearing parts. Due to this restriction, a new technology to reinforce with fibres the thermoplastic filaments was developed in the last years. Continuous fibre reinforced thermoplastic composites (CFRTPC) printers are taking this technology to a whole new level in terms of efficient production and mechanical properties. Static mechanical properties, as well as fatigue behaviour, were studied since in these types of loads a wide range of engineering dynamic applications can be envisaged. Tensile tests were performed to characterise the static mechanical properties. Fatigue tests were done to analyse the durability behaviour of the FDM composite materials, and the...

Research paper thumbnail of Study of dynamic behavior of a composite laminated material manufactured of the bark of Lata’s Palm “Bactris Guineensis”

Composite Structures, 2018

Abstract The use of alternative lignocellulosic raw materials for development of new engineering ... more Abstract The use of alternative lignocellulosic raw materials for development of new engineering composite materials is researched. The study is based on the Lata’s palm “Bactris Guineensis” bark as the main constituent for glued laminated composite material manufacturing. Static mechanical properties as well as fatigue behaviors were studied, since in these types of loads a wide range of engineering dynamic applications can be envisaged. Tensile and hardness testing were performed for the characterization of static and mechanical properties. Additionally, fatigue testing was used to analyze the durability behavior of the composite materials obtained and the fracture surface was analyzed by SEM microscopy. Vickers hardness and tensile resistance at the exterior bark demonstrated that it is the hardest and most resistant zone with 27,5 Vickers and 354 MPa values respectively. During fatigue testing, the temporary life zone was obtained from the stress vs. number of cycles curve (S vs Nf). The Basquin’s equation parameters were found ( S = A Â · N f b ), with: A = 321 MPa. and b = −0,060. Finally, in order to evaluate the potential use of glued laminated Lata’s Palm as a composite material constituent its mechanical characterization was performed.

Research paper thumbnail of Finite Element Analysis for Palm Oil Bunches Press Shaft Fractured in Service

Key Engineering Materials, 2018

In this work, the behaviour of a palm fruit bunch press shaft is investigated, which has presente... more In this work, the behaviour of a palm fruit bunch press shaft is investigated, which has presented early failure several times, not reaching its expected lifetime. The study allows determining the failure mode of the shaft by using the finite element method (FEM). The model is used to estimate the load produced by the fruit bunches over the worm screw and transferred to the shaft. Geometrical analysis of the shaft shape helps to determine failure mode. The stress and strain fields are obtained to determine the critical points of the design, in order to propose modifications to the shaft design. Moreover, after a short time of operation, the structure presented plastic deformation, the hexagonal shape in the shaft is repaired using a welding procedure, as showed metallographic and hardness results obtained on surface and subsurface level of the affected area for the fractographic analysis. This is compared with a raw steel SAE AISI 4340 under tempered like original condition.

Research paper thumbnail of Static and Fatigue Behaviour of Continuous Fibre Reinforced Thermoplastic Composites Manufactured by Fused Deposition Modelling Technique

International Journal of Fatigue, 2019

Additive manufacturing (AM) technologies have been applied with success in many applications, bei... more Additive manufacturing (AM) technologies have been applied with success in many applications, being fused deposition modelling (FDM) the most widely used AM technique for fabricating thermoplastic pieces. The thermoplastic parts made by FDM present lack of strength and low stiffness, as required for fully functional and loadbearing parts. Due to this restriction, a new technology to reinforce with fibres the thermoplastic filaments was developed in the last years. Continuous fibre reinforced thermoplastic composites (CFRTPC) printers are taking this technology to a whole new level in terms of efficient production and mechanical properties. Static mechanical properties, as well as fatigue behaviour, were studied since in these types of loads a wide range of engineering dynamic applications can be envisaged. Tensile tests were performed to characterise the static mechanical properties. Fatigue tests were done to analyse the durability behaviour of the FDM composite materials, and the fracture surface was analysed by SEM microscopy. The results showed that carbon fibre isotropic layers had the higher ultimate tensile stress, with 165 MPa. From fatigue tests, stress vs. number of cycles curves (S vs Nf) in the temporary life zone were obtained. It is observed from the results that specimens with nylon matrix, triangular filling pattern and matrix density of 20%, reinforced with carbon fibre at 0-degrees, showed better fatigue performance, increasing significantly the number of cycles before rupture of the specimen. The parameters for the Basquin's equation were found (= •), with A=206 MPa, and b=-0,039. Accordingly, mechanical characterization of continuous fibre reinforced thermoplastic composites was investigated, showing the potential use as a composite material for engineering applications.

Research paper thumbnail of Evaluation of Tensile Properties and Damage of Continuous Fibre Reinforced 3D-Printed Parts

Key Engineering Materials, 2018

Three-dimensional (3D) printing technology has been traditionally used for the production of prot... more Three-dimensional (3D) printing technology has been traditionally used for the production of prototypes. Recently, developments in 3D printing using Fused Deposition Modelling (FDM) and reinforcement with continuous fibres (fiberglass and carbon fibre), have allowed the manufacture of functional prototypes, considerably improving the mechanical performance of the composite parts. In this work, we characterise the elastic tensile properties of fibre reinforced specimens, considering the variation of several parameters available during the printing process: fibre orientation, volume fraction, fill pattern, reinforcement distribution. Tensile tests were performed according to ASTM D638 to obtain Young’s modulus and ultimate strength for different material configurations available during the printing process. We also perform a fractographic analysis using Scanning Electron Microscopy (SEM) to give an insight of the failure mechanisms present in the specimens.

Research paper thumbnail of Indentation size effect of cortical bones submitted to different soft tissue removals

Journal of the Mechanical Behavior of Biomedical Materials, 2013

Properties of elasticity, hardness and viscosity are determined for the study of the visco-elasto... more Properties of elasticity, hardness and viscosity are determined for the study of the visco-elastoplastic behavior of bones. The mechanical properties are compared in two upright sections of the bone due to their anisotropy. Besides, influence of hydration treatments leading to structural modifications of collagen and ground substance contents of bones on the mechanical properties is studied on a femoral cortical bovine bone. The treatments applied to the bone are used by forensic anthropologists to remove the soft tissue and modifying the hydration degree coupled to the collagen content. From instrumented indentation experiments, the hardness is characterized by the macrohardness and a hardness length-scale factor stating the hardness-load dependence. The elastic modulus results from the application of the methodology of Oliver and Pharr (1992). The coefficient of viscosity is deduced from a rheological model representing the indenter time-displacement observed under the application of a constant load. As a result, all the mechanical properties are found to be lower in the transverse section in an extent depending on the hydration treatment, i.e. the different values are located between 5% and 25% for the hardness around 0.5GPa, between 25% and 40% for the elastic modulus around 20GPa and between 2% and 35% for the coefficient of viscosity around 60GPa.s. Unexpectedly, the elastic modulus to coefficient of viscosity ratio is found to be independent on the hydration treatment.

Research paper thumbnail of Investigación en ingeniería en Colombia

Revista UIS Ingenierías, 2020

Con el comienzo de una nueva década,se vislumbran fuertes cambios en muchos de los paradigmas de ... more Con el comienzo de una nueva década,se vislumbran fuertes cambios en muchos de los paradigmas de la ingeniería, y por supuesto, dichos cambios afectarán nuestra sociedad[1]. La aparición de tecnologías disruptivas como, por ejemplo, la inteligencia artificial, la manufactura aditiva, la realidad aumentada, plantean un nuevo escenario para la ingeniería, donde se fortalecerán los países que adopten oportunamente estasnuevas tecnologías.En este sentido, es importante hacer una valoración del estado actual de la investigación en el área de ingeniería en Colombia, y tratar de definir un escenario donde podamos hacer frente, de manera efectiva, a los nuevos retos que se plantean en esta nueva revolución industrial.

Research paper thumbnail of Impact Strength for 3D-Printed PA6 Polymer Composites under Temperature Changes

Journal of Manufacturing and Materials Processing

This paper shows how temperature influences impact energy for continuous fiber additively manufac... more This paper shows how temperature influences impact energy for continuous fiber additively manufactured (AM) polymer matrix composites. AM composites were fabricated with a nylon-based matrix and four continuous reinforcements: fiberglass, high-temperature fiberglass (HSHT), Kevlar, and carbon. The tested temperatures ranged from −40 to 90 °C. The chosen printed configuration for the lattice structure and fiber volume was the configuration that was found to perform the best in the literature, with a volumetric fiber content of 24.2%. Impact tests showed that the best response was fiberglass, HSHT, Kevlar, and carbon, in that order. The impact resistance was lowered at temperatures below ambient temperatures and above 50 °C. Additionally, each material’s impact energy was adjusted to third-degree polynomials to model results, with correlation factors above 92%. Finally, the failure analysis showed the damage mechanisms of matrix cracking, delamination in the printing direction, fiber ...

Research paper thumbnail of Impact Strength for 3D-Printed PA6 Polymer Composites under Temperature Changes

Manufacturing and Materials Processing, 2023

Abstract: This paper showshowtemperatureinfluencesimpactenergyforcontinuousfiberadditively manufa... more Abstract: This paper showshowtemperatureinfluencesimpactenergyforcontinuousfiberadditively manufactured (AM) polymer matrix composites. AM composites were fabricated with a nylon-based matrix and four continuous reinforcements: fiberglass, high-temperature fiberglass (HSHT), Kevlar, and carbon. The tested temperatures ranged from −40 to 90 ◦C. The chosen printed configuration for the lattice structure and fiber volume was the configuration that was found to perform the best in the literature, with a volumetric fiber content of 24.2%. Impact tests showed that the best response was fiberglass, HSHT, Kevlar, and carbon, in that order. The impact resistance was lowered at temperatures below ambient temperatures and above 50 ◦C. Additionally, each material’s impact energy was adjusted to third-degree polynomials to model results, with correlation factors above 92%. Finally, the failure analysis showed the damage mechanisms of matrix cracking, delamination in the printing direction, fiber tearing, and fiber pulling as failure mechanisms.

Research paper thumbnail of Impact Strength for 3D-Printed PA6 Polymer Composites under Temperature Changes

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Impact Strength for 3D-Printed PA6 Polymer Composites under Temperature Changes

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Cement system design used in anchorage wells for offshore deepwater production platforms: Event: Rio de Janeiro, Brasil

Revista de la Facultad de Ingeniería Universidad Central de Venezuela, Mar 1, 2013

Research paper thumbnail of Composite pipe: State of the art, stress analysis and first ply failure

HAL (Le Centre pour la Communication Scientifique Directe), Oct 17, 2016

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Distributed under a Creative Commons Attribution-NoDerivatives| 4.0 International License

Research paper thumbnail of Damage evolution in composite pipes using a continuum damage mechanics formulation

HAL (Le Centre pour la Communication Scientifique Directe), Jun 14, 2017

Composite pipes are replacing conventional steel pipes in oil and gas transport applications. The... more Composite pipes are replacing conventional steel pipes in oil and gas transport applications. Their strength is determined by specific failure criteria for composite materials, however, once the damage has initiated there exists an interest in knowing how it propagates or evolves in order to determine the remaining life of a pipe. After damage initiation, mechanisms like micro cracking, fiber rupture, fiber-matrix debonding and delamination can occur [1]. Continuum damage mechanics is a phenomenological theory for taking into account these mechanisms in the effects of the mechanical material behavior [2]. Currently, it exists a variety of damage models for composites laminates [3]. Ferry et al. [4] have proposed an anisotropic damage model for pipes with good agreement with experimental data. Other models are also developed or implemented for composite pipes for example in [5]. Solution of these models are indeed not very easy and usually an implementation in a FEA (Finite Element Analysis) code is needed. A common numerical method to solve for these equations is the return mapping algorithm. In this work, we study the numerical methods available for the solution of damage evolution in composite laminates by the application of an industrial example: composite pipes.

Research paper thumbnail of A new model to determine the hardness of thin films

HAL (Le Centre pour la Communication Scientifique Directe), 2004

Research paper thumbnail of Methods for treating damage in composite materials, an application to pipes

HAL (Le Centre pour la Communication Scientifique Directe), Aug 16, 2017

Research paper thumbnail of Stress analysis, first ply failure and damage of a multilayer composite pipe for different boundary conditions

HAL (Le Centre pour la Communication Scientifique Directe), May 25, 2017

Research paper thumbnail of Mechanical behavior analysis of a vertical axis wind turbine blade made with fique-epoxy composite using FEM

Procedia Computer Science

Research paper thumbnail of Damage in Fibreglass Composite Laminates Used for Pipes

Key Engineering Materials, 2018

In this work, we present a model for the initiation and evolution of damage for a composite fibre... more In this work, we present a model for the initiation and evolution of damage for a composite fibre-reinforced pipe used in the Oil & Gas industry, based on a commercially available pipe. A continuum damage mechanics model was employed to determine the initiation and evolution of damage. This model was implemented using finite element analysis to investigate the performance of the commercial composite pipe. Initially, the material properties were obtained from experimental data and fitting with static structural simulations. Then, FE simulations with damage were performed, considering three different boundary conditions: open, closed (pressure-vessel type) and fixed ends, the load considered was internal pressure. Results showed differences not only in the stress distribution but on the damage initiation and evolution along the geometry of the pipe. These differences in the damage initiation and propagation can be explained as the result of different axial-hoop stress ratio.

Research paper thumbnail of A model for hardness determination of thin coatings from standard micro-indentation tests

Surface and Coatings Technology, 2005

Determination of surface hardness of thin films using standard micro-indentation testers has to a... more Determination of surface hardness of thin films using standard micro-indentation testers has to address the problem of the range of indentation loads available with these testers. In fact, they are often too high to allow the direct determination of the film hardness without involving a contribution of the substrate. As a consequence, the calculated hardness value is not the hardness of the film but an apparent surface hardness. Since this “composite” hardness is the result of two contributions, models are necessary to separate them in order to determine the true film hardness. The application of such models may however require the introduction of coefficients or data or involve some other adjustment method. In order to avoid the need for such other data parameter, we propose a new model, which gives predictions in good accordance with the average ones of the other models.

Research paper thumbnail of Fatigue in Continuous Fibre Reinforced Thermoplastic Composites

Additive manufacturing (AM) technologies have been applied with success in many applications, bei... more Additive manufacturing (AM) technologies have been applied with success in many applications, being fused deposition modelling (FDM) the most widely used AM technique for fabricating thermoplastic pieces. The thermoplastic parts made by FDM present lack of strength and low stiffness, as required for fully functional and load-bearing parts. Due to this restriction, a new technology to reinforce with fibres the thermoplastic filaments was developed in the last years. Continuous fibre reinforced thermoplastic composites (CFRTPC) printers are taking this technology to a whole new level in terms of efficient production and mechanical properties. Static mechanical properties, as well as fatigue behaviour, were studied since in these types of loads a wide range of engineering dynamic applications can be envisaged. Tensile tests were performed to characterise the static mechanical properties. Fatigue tests were done to analyse the durability behaviour of the FDM composite materials, and the...

Research paper thumbnail of Study of dynamic behavior of a composite laminated material manufactured of the bark of Lata’s Palm “Bactris Guineensis”

Composite Structures, 2018

Abstract The use of alternative lignocellulosic raw materials for development of new engineering ... more Abstract The use of alternative lignocellulosic raw materials for development of new engineering composite materials is researched. The study is based on the Lata’s palm “Bactris Guineensis” bark as the main constituent for glued laminated composite material manufacturing. Static mechanical properties as well as fatigue behaviors were studied, since in these types of loads a wide range of engineering dynamic applications can be envisaged. Tensile and hardness testing were performed for the characterization of static and mechanical properties. Additionally, fatigue testing was used to analyze the durability behavior of the composite materials obtained and the fracture surface was analyzed by SEM microscopy. Vickers hardness and tensile resistance at the exterior bark demonstrated that it is the hardest and most resistant zone with 27,5 Vickers and 354 MPa values respectively. During fatigue testing, the temporary life zone was obtained from the stress vs. number of cycles curve (S vs Nf). The Basquin’s equation parameters were found ( S = A Â · N f b ), with: A = 321 MPa. and b = −0,060. Finally, in order to evaluate the potential use of glued laminated Lata’s Palm as a composite material constituent its mechanical characterization was performed.

Research paper thumbnail of Finite Element Analysis for Palm Oil Bunches Press Shaft Fractured in Service

Key Engineering Materials, 2018

In this work, the behaviour of a palm fruit bunch press shaft is investigated, which has presente... more In this work, the behaviour of a palm fruit bunch press shaft is investigated, which has presented early failure several times, not reaching its expected lifetime. The study allows determining the failure mode of the shaft by using the finite element method (FEM). The model is used to estimate the load produced by the fruit bunches over the worm screw and transferred to the shaft. Geometrical analysis of the shaft shape helps to determine failure mode. The stress and strain fields are obtained to determine the critical points of the design, in order to propose modifications to the shaft design. Moreover, after a short time of operation, the structure presented plastic deformation, the hexagonal shape in the shaft is repaired using a welding procedure, as showed metallographic and hardness results obtained on surface and subsurface level of the affected area for the fractographic analysis. This is compared with a raw steel SAE AISI 4340 under tempered like original condition.

Research paper thumbnail of Static and Fatigue Behaviour of Continuous Fibre Reinforced Thermoplastic Composites Manufactured by Fused Deposition Modelling Technique

International Journal of Fatigue, 2019

Additive manufacturing (AM) technologies have been applied with success in many applications, bei... more Additive manufacturing (AM) technologies have been applied with success in many applications, being fused deposition modelling (FDM) the most widely used AM technique for fabricating thermoplastic pieces. The thermoplastic parts made by FDM present lack of strength and low stiffness, as required for fully functional and loadbearing parts. Due to this restriction, a new technology to reinforce with fibres the thermoplastic filaments was developed in the last years. Continuous fibre reinforced thermoplastic composites (CFRTPC) printers are taking this technology to a whole new level in terms of efficient production and mechanical properties. Static mechanical properties, as well as fatigue behaviour, were studied since in these types of loads a wide range of engineering dynamic applications can be envisaged. Tensile tests were performed to characterise the static mechanical properties. Fatigue tests were done to analyse the durability behaviour of the FDM composite materials, and the fracture surface was analysed by SEM microscopy. The results showed that carbon fibre isotropic layers had the higher ultimate tensile stress, with 165 MPa. From fatigue tests, stress vs. number of cycles curves (S vs Nf) in the temporary life zone were obtained. It is observed from the results that specimens with nylon matrix, triangular filling pattern and matrix density of 20%, reinforced with carbon fibre at 0-degrees, showed better fatigue performance, increasing significantly the number of cycles before rupture of the specimen. The parameters for the Basquin's equation were found (= •), with A=206 MPa, and b=-0,039. Accordingly, mechanical characterization of continuous fibre reinforced thermoplastic composites was investigated, showing the potential use as a composite material for engineering applications.

Research paper thumbnail of Evaluation of Tensile Properties and Damage of Continuous Fibre Reinforced 3D-Printed Parts

Key Engineering Materials, 2018

Three-dimensional (3D) printing technology has been traditionally used for the production of prot... more Three-dimensional (3D) printing technology has been traditionally used for the production of prototypes. Recently, developments in 3D printing using Fused Deposition Modelling (FDM) and reinforcement with continuous fibres (fiberglass and carbon fibre), have allowed the manufacture of functional prototypes, considerably improving the mechanical performance of the composite parts. In this work, we characterise the elastic tensile properties of fibre reinforced specimens, considering the variation of several parameters available during the printing process: fibre orientation, volume fraction, fill pattern, reinforcement distribution. Tensile tests were performed according to ASTM D638 to obtain Young’s modulus and ultimate strength for different material configurations available during the printing process. We also perform a fractographic analysis using Scanning Electron Microscopy (SEM) to give an insight of the failure mechanisms present in the specimens.

Research paper thumbnail of Indentation size effect of cortical bones submitted to different soft tissue removals

Journal of the Mechanical Behavior of Biomedical Materials, 2013

Properties of elasticity, hardness and viscosity are determined for the study of the visco-elasto... more Properties of elasticity, hardness and viscosity are determined for the study of the visco-elastoplastic behavior of bones. The mechanical properties are compared in two upright sections of the bone due to their anisotropy. Besides, influence of hydration treatments leading to structural modifications of collagen and ground substance contents of bones on the mechanical properties is studied on a femoral cortical bovine bone. The treatments applied to the bone are used by forensic anthropologists to remove the soft tissue and modifying the hydration degree coupled to the collagen content. From instrumented indentation experiments, the hardness is characterized by the macrohardness and a hardness length-scale factor stating the hardness-load dependence. The elastic modulus results from the application of the methodology of Oliver and Pharr (1992). The coefficient of viscosity is deduced from a rheological model representing the indenter time-displacement observed under the application of a constant load. As a result, all the mechanical properties are found to be lower in the transverse section in an extent depending on the hydration treatment, i.e. the different values are located between 5% and 25% for the hardness around 0.5GPa, between 25% and 40% for the elastic modulus around 20GPa and between 2% and 35% for the coefficient of viscosity around 60GPa.s. Unexpectedly, the elastic modulus to coefficient of viscosity ratio is found to be independent on the hydration treatment.

Research paper thumbnail of Investigación en ingeniería en Colombia

Revista UIS Ingenierías, 2020

Con el comienzo de una nueva década,se vislumbran fuertes cambios en muchos de los paradigmas de ... more Con el comienzo de una nueva década,se vislumbran fuertes cambios en muchos de los paradigmas de la ingeniería, y por supuesto, dichos cambios afectarán nuestra sociedad[1]. La aparición de tecnologías disruptivas como, por ejemplo, la inteligencia artificial, la manufactura aditiva, la realidad aumentada, plantean un nuevo escenario para la ingeniería, donde se fortalecerán los países que adopten oportunamente estasnuevas tecnologías.En este sentido, es importante hacer una valoración del estado actual de la investigación en el área de ingeniería en Colombia, y tratar de definir un escenario donde podamos hacer frente, de manera efectiva, a los nuevos retos que se plantean en esta nueva revolución industrial.