This experimental work is aimed at the influence of seawater immersion in low impact energy behav... more This experimental work is aimed at the influence of seawater immersion in low impact energy behavior of a novel Colombian fique fiber reinforced bio-resin laminate. Such material was manufactured by vacuum infusion. The specimens were immersed in seawater during a bioactivity period of six months. Low energy impact tests were performed in order to obtain the penetration and perforation threshold according to energy profiles. The damage extent was characterized by means of Ultrasonics. Tensile stress tests were also performed and the breaking surfaces were analyzed by Scanning Electron Microscopy. The results revealed that the new biocomposite, after seawater immersion, has higher penetration and perforation thresholds than the biocomposite without immersion. Tensile test results show stiffness lost and increase of elongation at break. This behavior of the immersed biocomposite is due to a plasticization process of the material.
The use of viscoelastic sheets in the hull of vessels built from GFRP has been raised in previous... more The use of viscoelastic sheets in the hull of vessels built from GFRP has been raised in previous works as an option to protect the vessel from the destructive damage of slamming. The present work proposes its use in boats previously built by adhering to the outside of the hulls of the ships. Its installation process is shown, and this new type of installation is compared. Through impact tests with GFRP panels, it is shown that the viscoelastic material maintains its property of absorbing slamming energy and protecting the interior of the laminate. Fatigue tests on the order of 5x104 cycles are carried out to evaluate the impact force, the accelerations that deform the laminate and the virtual energy work imposed on the panel. This option shows that designers have a new option to protect the hull of already built boats.
Obtaining lighter materials, with more toughness and higher impact resistance, is getting larger ... more Obtaining lighter materials, with more toughness and higher impact resistance, is getting larger is becoming of high interest in the current industry. It is possible to find lots of examples of different materials inspired in nature with gradient properties that are used for the development of hybrid materials. Also, various studies in granular materials show the possibility of confinement of the impact energy inside the material itself, allowing the decomposition of the initial pulse into several weaker pulses, the energy dissipation through several mechanisms and the gradual release of the non-dissipated energy. This article congregates the results of a preliminary design process and the fabrication of a granular hybrid material (ABS polymeric matrix and 0.25% of carbon nano layers as a reinforcement) initially in the form of a filament, subsequently utilised in the fabrication of viscoelastic layers. These layers will be fabricated using 3D printing techniques and will be introdu...
Composite materials are widely becoming the choices for many structural applications especially i... more Composite materials are widely becoming the choices for many structural applications especially in offshore industry fields, driven by lightweight and corrosion resistance compared to traditional metal. Until recently, interest has focused on the use of them in support structures of offshore wind turbines (OWT). The prospect of deep water exploration and multi-MW turbine’s application is generating a new impetus for high performance material, which aims at increasing load bearing capability and if possible saving weight and cost simultaneously. Performance of a new fiber-metal hybrid material developed specifically for the marine industry is presented in this paper. Simulation models of benchmark examples with the new hybrid material were analyzed in different load cases. Several improved parameters are put forward in order to explicit the performance of this new material to be used in towers of OWT clearly. Results show that within certain limits and with optimal configurations, th...
To be able to predict the strength of adhesive joints accurately, correct material data of adhesi... more To be able to predict the strength of adhesive joints accurately, correct material data of adhesives are essential. Hence, it is critical to develop reliable testing methods to obtain the constitutive behaviour of adhesive layers. In use, adhesives are constrained to thin layers. Thus, an adhesive constrained into a layer is expected to behave differently compared to the adhesive as a bulk material. Under loading, the size of the Failure Process Zone (FPZ) in the adhesive layer is often much larger than the thickness of the layer. Thus, the small scale FPZ condition is not fulfilled and the traditional Linear Elastic Fracture Mechanics (LEFM) can not be applied. At the same time, experiments show that test specimens are prone to produce unstable crack propagation and combined adhesive/cohesive fracture patterns appear frequently, especially when mixed mode loading (peel and shear) is involved. Cohesive law should be taken as the basic fracture property for adhesives characterization...
Actas De 47o Congreso De Ingenieria Naval E Industria Maritima 47o Congreso De Ingenieria Naval E Industria Maritima 16 10 2008 17 10 2008 Palma De Mallorca Espana, 2008
Proceeding of the VI International Ship Design & Naval Engineering Congress (CIDIN) and XXVI Pan-American Congress of Naval Engineering, Maritime Transportation and Port Engineering (COPINAVAL)
A laboratory methodology is proposed, which allows to evaluate the evolution of intralaminar and ... more A laboratory methodology is proposed, which allows to evaluate the evolution of intralaminar and interlaminar damage, for the hull of vessels built with reinforced polymer and fiberglass - (GFRP) modified viscoelastically, subjected to low energy impacts reproducing the blow of slamming during your navigation at half speed. The method proposes the reproduction of the phenomenon with the equipment designed for this purpose, analyzing the energy absorbed and the energy returned based on the results obtained by vertical impacts of the same energy level. Interlaminar and intralaminar delaminations are visually appreciated and correlated with the results obtained through the use of image analysis software. The deformations have been evaluated with strain gauges supported by the respective mathematical formulation. The advances in the use of new generation viscoelastic layers and their future perspectives are shown.
The insertion of a viscoelastic layer is proposed to mitigate damage by vertical impact. For this... more The insertion of a viscoelastic layer is proposed to mitigate damage by vertical impact. For this purpose, unmodified GFRP panels and others modified with the viscoelastic sheet are made. With the use of an accelerometer, the force of the vertical impacts due to weight drop on the panels is measured, in order to quantify the critical points of damage. The absorbed energy is obtained through the mathematical formulation developed for this purpose. Damage is observed qualitatively by characterizing with penetrating inks to establish a comparison between viscoelastic-modified panels and non-modified panels. Impact force versus time curves are presented to assess damage mitigation in the GFRP. The benefits of the modification are evaluated, and its protection to the laminate is checked.
A laboratory methodology is proposed, which allows to evaluate the evolution of intralaminar and ... more A laboratory methodology is proposed, which allows to evaluate the evolution of intralaminar and interlaminar damage, for the hull of vessels built with reinforced polymer and fiberglass - (GFRP) modified viscoelastically, subjected to low energy impacts reproducing the blow of slamming during your navigation at half speed. The method proposes the reproduction of the phenomenon with the equipment designed for this purpose, analyzing the energy absorbed and the energy returned based on the results obtained by vertical impacts of the same energy level. Interlaminar and intralaminar delaminations are visually appreciated and correlated with the results obtained through the use of image analysis software. The deformations have been evaluated with strain gauges supported by the respective mathematical formulation. The advances in the use of new generation viscoelastic layers and their future perspectives are shown.
SE HA MODELIZADO LA SOLDADURA DE ACEROS HSLA MICROALEADOS, CONCRETAMENTE EN EN LO REFERIDO A: -CI... more SE HA MODELIZADO LA SOLDADURA DE ACEROS HSLA MICROALEADOS, CONCRETAMENTE EN EN LO REFERIDO A: -CICLOS TERMICOS -CRECIMIENTO DE GRANO -DISOLUCION YCRECIMIENTO PRECIPITADOS -PERFILES DE DUREZA EN LA ZAC. DEL MODELO SE HA OBTENIDO UN PROGRAMA DE ORDENADOR. LOS RESULTADOS HAN SIDO CONTRASTADOS CON EXPERIMENTOS REALES. EL MATERIAL, UNA VEZ CARACTERIZADO POR DIVERSAS TECNICAS, HA SIDO SOMETIDO A ENSAYOS EN CAMARAS DE SOLDADURA. LAS MICROESTRUCTURAS OBERNIDAS HA SIDO ANALIZADAS Y RELACIONADAS CON LOS PARAMETROS DE SOLDEO. LAS MEDIDAS HA SIDO ENFRENTADAS A LAS PREDICCIONES DEL MODELO.
Planing hull vessel built with polymer matrix laminates and fiberglass reinforcements (GFRP) suff... more Planing hull vessel built with polymer matrix laminates and fiberglass reinforcements (GFRP) suffer structural damage due to the phenomenon of slamming during navigation, due to the impact of the boat hull on the free surface of the water at high speed. A modification in the manufacture of the laminates for these fast boats is proposed, consisting of the insertion of an additional layer of a hybrid material, formed by elastomer encapsulated in an ABS polymer cell. Using GFRP specimens made from pre-impregnated material and reproducing the characteristic impacts of slamming, it is possible to compare the modified material with the introduction of the viscoelastic layers with the response under the same conditions as the unmodified laminates. Additionally, the panels have been tested using impacts due to weight drop at different energies, which allow determining the material damage threshold as a function of the energy absorbed, and to establish a comparison with the GFRP panels modif...
Fatigue is one of the main failure modes in marine structures, and it is caused by the strong cyc... more Fatigue is one of the main failure modes in marine structures, and it is caused by the strong cyclic characteristics of the loads they support. This failure mode is amplified in areas of high stress concentration, such as at the intersection of primary and secondary elements. In this paper, a two-phase study is proposed that compares numerical and experimental results using a digital image correlation technique. The described procedure establishes selection, design, and scantling criteria and provides recommendations for the design of the transverse structure using specimens with different geometries. These geometries correspond to different designs for the transverse primary structure that use a longitudinal secondary stiffener with variable thickness and longitudinal spacing to transverse in a dynamic and quasi-static regime. The stress state for this regime is calculated based on the biaxiality indication concept, which uses the fatigue phenomenon (safety factor and sensitivity c...
Este articulo documenta el planteamiento, la metodologia y los primeros resultados de un plan de ... more Este articulo documenta el planteamiento, la metodologia y los primeros resultados de un plan de monitorizacion detallada del esfuerzo y de asistencia a actividades presenciales por parte de los estudiantes de las titulaciones ofertadas por la Escuela Tecnica Superior de Ingenieros Navales de la Universidad Politecnica de Madrid durante el segundo cuatrimestre del curso 2011-2012. Se ha establecido un sistema mecanico de recogida de datos de esfuerzo por parte de los estudiantes utilizando una hoja tipo test especialmente configurada al efecto. Se pasa una hoja en todas y cada una de las actividades presenciales realizadas y en la hoja se solicita informacion sobre el trabajo "fuera de clase". Se documenta en este articulo como se ha estructurado esa hoja, que tipo de datos se recogen, como se tratan mediante una base de datos creada al efecto, que tipo de analisis se puede realizar y que resultados preliminares obtenemos de dichos analisis.
This experimental work is aimed at the influence of seawater immersion in low impact energy behav... more This experimental work is aimed at the influence of seawater immersion in low impact energy behavior of a novel Colombian fique fiber reinforced bio-resin laminate. Such material was manufactured by vacuum infusion. The specimens were immersed in seawater during a bioactivity period of six months. Low energy impact tests were performed in order to obtain the penetration and perforation threshold according to energy profiles. The damage extent was characterized by means of Ultrasonics. Tensile stress tests were also performed and the breaking surfaces were analyzed by Scanning Electron Microscopy. The results revealed that the new biocomposite, after seawater immersion, has higher penetration and perforation thresholds than the biocomposite without immersion. Tensile test results show stiffness lost and increase of elongation at break. This behavior of the immersed biocomposite is due to a plasticization process of the material.
The use of viscoelastic sheets in the hull of vessels built from GFRP has been raised in previous... more The use of viscoelastic sheets in the hull of vessels built from GFRP has been raised in previous works as an option to protect the vessel from the destructive damage of slamming. The present work proposes its use in boats previously built by adhering to the outside of the hulls of the ships. Its installation process is shown, and this new type of installation is compared. Through impact tests with GFRP panels, it is shown that the viscoelastic material maintains its property of absorbing slamming energy and protecting the interior of the laminate. Fatigue tests on the order of 5x104 cycles are carried out to evaluate the impact force, the accelerations that deform the laminate and the virtual energy work imposed on the panel. This option shows that designers have a new option to protect the hull of already built boats.
Obtaining lighter materials, with more toughness and higher impact resistance, is getting larger ... more Obtaining lighter materials, with more toughness and higher impact resistance, is getting larger is becoming of high interest in the current industry. It is possible to find lots of examples of different materials inspired in nature with gradient properties that are used for the development of hybrid materials. Also, various studies in granular materials show the possibility of confinement of the impact energy inside the material itself, allowing the decomposition of the initial pulse into several weaker pulses, the energy dissipation through several mechanisms and the gradual release of the non-dissipated energy. This article congregates the results of a preliminary design process and the fabrication of a granular hybrid material (ABS polymeric matrix and 0.25% of carbon nano layers as a reinforcement) initially in the form of a filament, subsequently utilised in the fabrication of viscoelastic layers. These layers will be fabricated using 3D printing techniques and will be introdu...
Composite materials are widely becoming the choices for many structural applications especially i... more Composite materials are widely becoming the choices for many structural applications especially in offshore industry fields, driven by lightweight and corrosion resistance compared to traditional metal. Until recently, interest has focused on the use of them in support structures of offshore wind turbines (OWT). The prospect of deep water exploration and multi-MW turbine’s application is generating a new impetus for high performance material, which aims at increasing load bearing capability and if possible saving weight and cost simultaneously. Performance of a new fiber-metal hybrid material developed specifically for the marine industry is presented in this paper. Simulation models of benchmark examples with the new hybrid material were analyzed in different load cases. Several improved parameters are put forward in order to explicit the performance of this new material to be used in towers of OWT clearly. Results show that within certain limits and with optimal configurations, th...
To be able to predict the strength of adhesive joints accurately, correct material data of adhesi... more To be able to predict the strength of adhesive joints accurately, correct material data of adhesives are essential. Hence, it is critical to develop reliable testing methods to obtain the constitutive behaviour of adhesive layers. In use, adhesives are constrained to thin layers. Thus, an adhesive constrained into a layer is expected to behave differently compared to the adhesive as a bulk material. Under loading, the size of the Failure Process Zone (FPZ) in the adhesive layer is often much larger than the thickness of the layer. Thus, the small scale FPZ condition is not fulfilled and the traditional Linear Elastic Fracture Mechanics (LEFM) can not be applied. At the same time, experiments show that test specimens are prone to produce unstable crack propagation and combined adhesive/cohesive fracture patterns appear frequently, especially when mixed mode loading (peel and shear) is involved. Cohesive law should be taken as the basic fracture property for adhesives characterization...
Actas De 47o Congreso De Ingenieria Naval E Industria Maritima 47o Congreso De Ingenieria Naval E Industria Maritima 16 10 2008 17 10 2008 Palma De Mallorca Espana, 2008
Proceeding of the VI International Ship Design & Naval Engineering Congress (CIDIN) and XXVI Pan-American Congress of Naval Engineering, Maritime Transportation and Port Engineering (COPINAVAL)
A laboratory methodology is proposed, which allows to evaluate the evolution of intralaminar and ... more A laboratory methodology is proposed, which allows to evaluate the evolution of intralaminar and interlaminar damage, for the hull of vessels built with reinforced polymer and fiberglass - (GFRP) modified viscoelastically, subjected to low energy impacts reproducing the blow of slamming during your navigation at half speed. The method proposes the reproduction of the phenomenon with the equipment designed for this purpose, analyzing the energy absorbed and the energy returned based on the results obtained by vertical impacts of the same energy level. Interlaminar and intralaminar delaminations are visually appreciated and correlated with the results obtained through the use of image analysis software. The deformations have been evaluated with strain gauges supported by the respective mathematical formulation. The advances in the use of new generation viscoelastic layers and their future perspectives are shown.
The insertion of a viscoelastic layer is proposed to mitigate damage by vertical impact. For this... more The insertion of a viscoelastic layer is proposed to mitigate damage by vertical impact. For this purpose, unmodified GFRP panels and others modified with the viscoelastic sheet are made. With the use of an accelerometer, the force of the vertical impacts due to weight drop on the panels is measured, in order to quantify the critical points of damage. The absorbed energy is obtained through the mathematical formulation developed for this purpose. Damage is observed qualitatively by characterizing with penetrating inks to establish a comparison between viscoelastic-modified panels and non-modified panels. Impact force versus time curves are presented to assess damage mitigation in the GFRP. The benefits of the modification are evaluated, and its protection to the laminate is checked.
A laboratory methodology is proposed, which allows to evaluate the evolution of intralaminar and ... more A laboratory methodology is proposed, which allows to evaluate the evolution of intralaminar and interlaminar damage, for the hull of vessels built with reinforced polymer and fiberglass - (GFRP) modified viscoelastically, subjected to low energy impacts reproducing the blow of slamming during your navigation at half speed. The method proposes the reproduction of the phenomenon with the equipment designed for this purpose, analyzing the energy absorbed and the energy returned based on the results obtained by vertical impacts of the same energy level. Interlaminar and intralaminar delaminations are visually appreciated and correlated with the results obtained through the use of image analysis software. The deformations have been evaluated with strain gauges supported by the respective mathematical formulation. The advances in the use of new generation viscoelastic layers and their future perspectives are shown.
SE HA MODELIZADO LA SOLDADURA DE ACEROS HSLA MICROALEADOS, CONCRETAMENTE EN EN LO REFERIDO A: -CI... more SE HA MODELIZADO LA SOLDADURA DE ACEROS HSLA MICROALEADOS, CONCRETAMENTE EN EN LO REFERIDO A: -CICLOS TERMICOS -CRECIMIENTO DE GRANO -DISOLUCION YCRECIMIENTO PRECIPITADOS -PERFILES DE DUREZA EN LA ZAC. DEL MODELO SE HA OBTENIDO UN PROGRAMA DE ORDENADOR. LOS RESULTADOS HAN SIDO CONTRASTADOS CON EXPERIMENTOS REALES. EL MATERIAL, UNA VEZ CARACTERIZADO POR DIVERSAS TECNICAS, HA SIDO SOMETIDO A ENSAYOS EN CAMARAS DE SOLDADURA. LAS MICROESTRUCTURAS OBERNIDAS HA SIDO ANALIZADAS Y RELACIONADAS CON LOS PARAMETROS DE SOLDEO. LAS MEDIDAS HA SIDO ENFRENTADAS A LAS PREDICCIONES DEL MODELO.
Planing hull vessel built with polymer matrix laminates and fiberglass reinforcements (GFRP) suff... more Planing hull vessel built with polymer matrix laminates and fiberglass reinforcements (GFRP) suffer structural damage due to the phenomenon of slamming during navigation, due to the impact of the boat hull on the free surface of the water at high speed. A modification in the manufacture of the laminates for these fast boats is proposed, consisting of the insertion of an additional layer of a hybrid material, formed by elastomer encapsulated in an ABS polymer cell. Using GFRP specimens made from pre-impregnated material and reproducing the characteristic impacts of slamming, it is possible to compare the modified material with the introduction of the viscoelastic layers with the response under the same conditions as the unmodified laminates. Additionally, the panels have been tested using impacts due to weight drop at different energies, which allow determining the material damage threshold as a function of the energy absorbed, and to establish a comparison with the GFRP panels modif...
Fatigue is one of the main failure modes in marine structures, and it is caused by the strong cyc... more Fatigue is one of the main failure modes in marine structures, and it is caused by the strong cyclic characteristics of the loads they support. This failure mode is amplified in areas of high stress concentration, such as at the intersection of primary and secondary elements. In this paper, a two-phase study is proposed that compares numerical and experimental results using a digital image correlation technique. The described procedure establishes selection, design, and scantling criteria and provides recommendations for the design of the transverse structure using specimens with different geometries. These geometries correspond to different designs for the transverse primary structure that use a longitudinal secondary stiffener with variable thickness and longitudinal spacing to transverse in a dynamic and quasi-static regime. The stress state for this regime is calculated based on the biaxiality indication concept, which uses the fatigue phenomenon (safety factor and sensitivity c...
Este articulo documenta el planteamiento, la metodologia y los primeros resultados de un plan de ... more Este articulo documenta el planteamiento, la metodologia y los primeros resultados de un plan de monitorizacion detallada del esfuerzo y de asistencia a actividades presenciales por parte de los estudiantes de las titulaciones ofertadas por la Escuela Tecnica Superior de Ingenieros Navales de la Universidad Politecnica de Madrid durante el segundo cuatrimestre del curso 2011-2012. Se ha establecido un sistema mecanico de recogida de datos de esfuerzo por parte de los estudiantes utilizando una hoja tipo test especialmente configurada al efecto. Se pasa una hoja en todas y cada una de las actividades presenciales realizadas y en la hoja se solicita informacion sobre el trabajo "fuera de clase". Se documenta en este articulo como se ha estructurado esa hoja, que tipo de datos se recogen, como se tratan mediante una base de datos creada al efecto, que tipo de analisis se puede realizar y que resultados preliminares obtenemos de dichos analisis.
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