Automatic Discontinuity Classification of Wind-Turbine Blades using A-Scan-Based Convolutional Neural Network - SGEPRI Journals & Magazine
Recent development trends in wind power generation have increased the importance of the safe operation of wind-turbine blades (WTBs). To realize this objective, it is essential to inspect WTBs for any defects before they are placed into operation. However, conventional methods of fault inspection in WTBs can be rather difficult to implement, since complex curvatures that characterize the WTB structures must ensure accurate and reliable inspection. Moreover, it is considered useful if inspection results can be objectively and consistently classified and analyzed by an automated system and not by the subjective judgment of an inspector.....
7 avril 2020
2 avril 2020
Computational modelling of dynamic delamination in morphing composite blades and wings | Fallah | The International Journal of Multiphysics
Computational modelling of dynamic delamination in morphing composite blades and wings | Fallah | The International Journal of Multiphysics
Morphing blades have been promising in lifting restrictions on rated capacity of wind turbines and improving lift-to-drag ratio for aircraft wings at higher operational angles of attack. The present study focuses on one aspect of the response of morphing blades viz. dynamic delamination.
A numerical study of delamination in morphing composite blades is conducted. Both components i.e. the composite part and the stiffener are studied. The eXtended Finite Element Method (XFEM) and nonlocal continuum mechanics (peridynamics) have both been used to study fracture in the isotropic stiffener used in conjunction with the blade. As for the composite morphing blade, cohesive elements are used to represent the interlaminar weak zone and delamination has been studied under dynamic pulse loads. Intraply damage is studied using the nonlocal model as the peridynamic model is capable of addressing the problem adequately for the necessary level of sophistication.
Morphing blades have been promising in lifting restrictions on rated capacity of wind turbines and improving lift-to-drag ratio for aircraft wings at higher operational angles of attack. The present study focuses on one aspect of the response of morphing blades viz. dynamic delamination.
A numerical study of delamination in morphing composite blades is conducted. Both components i.e. the composite part and the stiffener are studied. The eXtended Finite Element Method (XFEM) and nonlocal continuum mechanics (peridynamics) have both been used to study fracture in the isotropic stiffener used in conjunction with the blade. As for the composite morphing blade, cohesive elements are used to represent the interlaminar weak zone and delamination has been studied under dynamic pulse loads. Intraply damage is studied using the nonlocal model as the peridynamic model is capable of addressing the problem adequately for the necessary level of sophistication.
Fractographic analysis of sandwich panels in a composite wind turbine blade using optical microscopy and X-ray computed tomography - ScienceDirect
Fractographic analysis of sandwich panels in a composite wind turbine blade using optical microscopy and X-ray computed tomography - ScienceDirect
This study provides a new perspective on the failure of sandwich panels in a composite wind turbine blade. Fractographic characteristics of fracture regions are examined thoroughly using optical microscopy and X-ray computed tomography......
This study provides a new perspective on the failure of sandwich panels in a composite wind turbine blade. Fractographic characteristics of fracture regions are examined thoroughly using optical microscopy and X-ray computed tomography......
A cuckoo search based neural network to predict fatigue life in rotor blade composites | Journal of Mechanical Engineering and Sciences
A cuckoo search based neural network to predict fatigue life in rotor blade composites | Journal of Mechanical Engineering and Sciences
In modern wind turbine blades industry, fiber-reinforced composites are mostly used for their good mechanical characteristics: high stiffness, low density and long fatigue life. Wind turbine blades are constructed in different structural elements from a variety of composite laminates, often including Unidirectional (UD) material in spars and multiple forms of Multidirectional (MD) in skins and webs. The purpose of this paper is to identify materials that have appropriate fiber orientations to improve fatigue life.....
In modern wind turbine blades industry, fiber-reinforced composites are mostly used for their good mechanical characteristics: high stiffness, low density and long fatigue life. Wind turbine blades are constructed in different structural elements from a variety of composite laminates, often including Unidirectional (UD) material in spars and multiple forms of Multidirectional (MD) in skins and webs. The purpose of this paper is to identify materials that have appropriate fiber orientations to improve fatigue life.....
1 avril 2020
A fatigue damage evaluation using local damage parameters for an offshore structure | Proceedings of the Institution of Civil Engineers - Maritime Engineering
A fatigue damage evaluation using local damage parameters for an offshore structure | Proceedings of the Institution of Civil Engineers - Maritime Engineering
In the fatigue design of offshore structures are normally used the waves and wind fatigue loading. Currently, fatigue analyses for fatigue damage accumulation assessment of this type of structure are based on S-N curves for welded structural components, hot-spot stress approach, and Palmgren-Miner law, according to design codes. Fatigue analyses of design codes and/or recommended practices are supported by global structural analysis. In this paper, a global-local fatigue methodology applied to an offshore jacket-type platform using a local approach through the notch strain damage parameter is proposed. The local approach is based on Neuber's rule combining with the Ramberg-Osgood description. Then, Coffin-Manson strain-life relation together with the Palmgren-Miner linear damage rule are used to evaluating the fatigue damage accumulation for the critical tubular welded joint. For the application of the Neuber's rule, the stress concentration factor values are calculated, according to Efthymiou's analytical equations, for the connection under consideration. This proposed methodology is compared with the simplified fatigue analysis presented in DNVGL-RP-C203 recommendations. These analyses are performed using wave loads from the scatter diagram collected in the North Sea, which were computed through the 5th Stokes order wave theory and Morrison formula.
In the fatigue design of offshore structures are normally used the waves and wind fatigue loading. Currently, fatigue analyses for fatigue damage accumulation assessment of this type of structure are based on S-N curves for welded structural components, hot-spot stress approach, and Palmgren-Miner law, according to design codes. Fatigue analyses of design codes and/or recommended practices are supported by global structural analysis. In this paper, a global-local fatigue methodology applied to an offshore jacket-type platform using a local approach through the notch strain damage parameter is proposed. The local approach is based on Neuber's rule combining with the Ramberg-Osgood description. Then, Coffin-Manson strain-life relation together with the Palmgren-Miner linear damage rule are used to evaluating the fatigue damage accumulation for the critical tubular welded joint. For the application of the Neuber's rule, the stress concentration factor values are calculated, according to Efthymiou's analytical equations, for the connection under consideration. This proposed methodology is compared with the simplified fatigue analysis presented in DNVGL-RP-C203 recommendations. These analyses are performed using wave loads from the scatter diagram collected in the North Sea, which were computed through the 5th Stokes order wave theory and Morrison formula.
Modeling and Simulation of Offshore Wind Farms for Smart Cities | IntechOpen
Modeling and Simulation of Offshore Wind Farms for Smart Cities | IntechOpen
Wind turbine models and simulations are widely available, but the simulation of a wind farm is scarce. This chapter presents a systematic approach to simulate an offshore wind farm for smart cities. The subsystems of several variable-pitch wind turbines, namely, rotor blades, drivetrain, and induction generator, are modeled to form a wind farm. The total output power of the wind farm by considering multiple wind turbines with the wake losses (using the Jensen wake model) can be simulated with any input wind speed. In order to validate the accuracy of the simulation, a case study was performed on a German offshore wind farm called NordseeOst. The simulation shows promising results with an average error of approximately 5% when compared with the real-time output of the wind farm. The results showed that the simulation of a wind farm that often impeded by the lack of exact information is feasible before any site implementation for smart cities.
Wind turbine models and simulations are widely available, but the simulation of a wind farm is scarce. This chapter presents a systematic approach to simulate an offshore wind farm for smart cities. The subsystems of several variable-pitch wind turbines, namely, rotor blades, drivetrain, and induction generator, are modeled to form a wind farm. The total output power of the wind farm by considering multiple wind turbines with the wake losses (using the Jensen wake model) can be simulated with any input wind speed. In order to validate the accuracy of the simulation, a case study was performed on a German offshore wind farm called NordseeOst. The simulation shows promising results with an average error of approximately 5% when compared with the real-time output of the wind farm. The results showed that the simulation of a wind farm that often impeded by the lack of exact information is feasible before any site implementation for smart cities.
23 mars 2020
Total acquiert la société Global Wind Power France
Total acquiert la société Global Wind Power France
Le groupe pétrolier Total vient d'acquérir, via sa filiale Total Quadran, la société Global Wind Power France, une entreprise spécialisée dans le développement, la mise en œuvre et la gestion de projets éoliens, qui compte aujourd'hui 17 salariés en France. Global Wind Power France est notamment à l'origine du parc éolien terrestre de Montdidier, construit en 2010 dans la Somme. Cette société détient aujourd'hui un portefeuille d'environ 1 000 mégawatts (MW) de projets éoliens...
Le groupe pétrolier Total vient d'acquérir, via sa filiale Total Quadran, la société Global Wind Power France, une entreprise spécialisée dans le développement, la mise en œuvre et la gestion de projets éoliens, qui compte aujourd'hui 17 salariés en France. Global Wind Power France est notamment à l'origine du parc éolien terrestre de Montdidier, construit en 2010 dans la Somme. Cette société détient aujourd'hui un portefeuille d'environ 1 000 mégawatts (MW) de projets éoliens...
21 mars 2020
Epidémie de covid-19 : mesures prises à destination des étudiants - Ministère de l'Enseignement supérieur, de la Recherche et de l'Innovation
Epidémie de covid-19 : mesures prises à destination des étudiants - Ministère de l'Enseignement supérieur, de la Recherche et de l'Innovation
Frédérique Vidal, ministre de l'Enseignement supérieur, de la Recherche et de l'Innovation, s'est entretenue avec les organisations étudiantes afin de dresser un premier état des mesures immédiates prises afin de soutenir les étudiants face à l'épidémie de covid-19.
Frédérique Vidal, ministre de l'Enseignement supérieur, de la Recherche et de l'Innovation, s'est entretenue avec les organisations étudiantes afin de dresser un premier état des mesures immédiates prises afin de soutenir les étudiants face à l'épidémie de covid-19.
MARIPOLDATA : un projet de recherche sur les négociations internationales et le rôle de la science pour la biodiversité marine - Ministère de l’Europe et des Affaires étrangères
MARIPOLDATA : un projet de recherche sur les négociations internationales et le rôle de la science pour la biodiversité marine - Ministère de l’Europe et des Affaires étrangères
La chercheuse franco-autrichienne Alice Vadrot a reçu en 2018 une prestigieuse bourse européenne pour monter le projet MARIPOLDATA. Avec son équipe, elle étudie notamment les négociations en cours aux Nations Unies autour d’un nouveau traité sur la biodiversité marine dans les eaux internationales.
La chercheuse franco-autrichienne Alice Vadrot a reçu en 2018 une prestigieuse bourse européenne pour monter le projet MARIPOLDATA. Avec son équipe, elle étudie notamment les négociations en cours aux Nations Unies autour d’un nouveau traité sur la biodiversité marine dans les eaux internationales.
Study on ice adhesion of composite anti-/deicing component under heating condition - Yishu Zhang, Long Chen, Hui Liu, 2020
Study on ice adhesion of composite anti-/deicing component under heating condition - Yishu Zhang, Long Chen, Hui Liu, 2020
An anti-/deicing component of composite materials for wind turbine blades is usually carried out under heating conditions. In order to study the ice adhesion properties of composite anti-/deicing component under heating conditions, an experimental platform for measuring ice adhesion force on composites was set up. Based on the heating parameters such as the heating temperature, heating voltage, and heating time, the experiments of ice adhesion of composite anti-/deicing component under deicing conditions were designed by orthogonal analysis. In this article, ice adhesion forces on composite anti-/deicing component were measured at −9.74°C, −11.58°C, −14.1°C, and −16.84°C by the proposed experiment platform, and the real ice adhesion forces under various heating parameters were measured. Through the analysis of experimental data and fitting method, the relationship between various factors and ice adhesion on composite anti-/deicing component was expounded. The influence weight of each heating parameter on the ice adhesion was analyzed. In addition, the mathematical model of ice adhesion on composite anti-/deicing component under deicing condition was established to describe the influence of deicing variables on ice adhesion in the experiments. According to the fitting function of the experimental data, the relationship between the heat consumption of composite anti-/deicing component and ice adhesion force in the process of heating is in accordance with the inverse power exponential expression, which reveals the internal relationship between ice adhesion force and energy consumption.
An anti-/deicing component of composite materials for wind turbine blades is usually carried out under heating conditions. In order to study the ice adhesion properties of composite anti-/deicing component under heating conditions, an experimental platform for measuring ice adhesion force on composites was set up. Based on the heating parameters such as the heating temperature, heating voltage, and heating time, the experiments of ice adhesion of composite anti-/deicing component under deicing conditions were designed by orthogonal analysis. In this article, ice adhesion forces on composite anti-/deicing component were measured at −9.74°C, −11.58°C, −14.1°C, and −16.84°C by the proposed experiment platform, and the real ice adhesion forces under various heating parameters were measured. Through the analysis of experimental data and fitting method, the relationship between various factors and ice adhesion on composite anti-/deicing component was expounded. The influence weight of each heating parameter on the ice adhesion was analyzed. In addition, the mathematical model of ice adhesion on composite anti-/deicing component under deicing condition was established to describe the influence of deicing variables on ice adhesion in the experiments. According to the fitting function of the experimental data, the relationship between the heat consumption of composite anti-/deicing component and ice adhesion force in the process of heating is in accordance with the inverse power exponential expression, which reveals the internal relationship between ice adhesion force and energy consumption.
Flexural fatigue behavior and life prediction of web reinforced GFRP-balsa sandwich beams - ScienceDirect
Flexural fatigue behavior and life prediction of web reinforced GFRP-balsa sandwich beams - ScienceDirect
This paper investigated static and fatigue bending behavior of sandwich beams using glass fiber reinforced polymer (GFRP) as skins and webs while balsa wood as core The failure modes, S-N curves, load-deflection behavior and stiffness degradation were obtained and compared The results showed that the fatigue failure modes of web reinforced sandwich beams varied with the web setting and load grade The web setting changed the failure mechanism and the materials were utilized in varying degrees in different specimens Fatigue life model based on damage modulus was proposed and proved appropriate to predict the fatigue damage and ultimate life.
This paper investigated static and fatigue bending behavior of sandwich beams using glass fiber reinforced polymer (GFRP) as skins and webs while balsa wood as core The failure modes, S-N curves, load-deflection behavior and stiffness degradation were obtained and compared The results showed that the fatigue failure modes of web reinforced sandwich beams varied with the web setting and load grade The web setting changed the failure mechanism and the materials were utilized in varying degrees in different specimens Fatigue life model based on damage modulus was proposed and proved appropriate to predict the fatigue damage and ultimate life.
15 mars 2020
US20200070448A1 - Repair strip and process for wind turbine leading edge protection tape - Google Patents
US20200070448A1 - Repair strip and process for wind turbine leading edge protection tape - Google Patents
A method is described for repairing the surface of rotor blades or aircraft wings, comprising (a) a composite substrate; and (b) a protection layer having at least one area of at least partial damage, the method comprising (i) optionally, removing at least part of the damaged part of the protection tape; (ii) optionally, reconstructing the surface of damaged composite substrate; (iii) optionally, applying primer solution to the surface of the composite substrate; (iv) optionally, applying a polymer solution, preferably in at least one organic solvent; (v) applying a repair patch of a polymer onto at least a part of the composite surface; (vi) applying heat so that the repair patch of a polymer tape melts and covers the damaged area, thereby forming a protection layer or applying a repair solution, preferably in at least one organic solvent, so that the repair patch of a polymer tape at least partially dissolves and covers the damaged area.
A method is described for repairing the surface of rotor blades or aircraft wings, comprising (a) a composite substrate; and (b) a protection layer having at least one area of at least partial damage, the method comprising (i) optionally, removing at least part of the damaged part of the protection tape; (ii) optionally, reconstructing the surface of damaged composite substrate; (iii) optionally, applying primer solution to the surface of the composite substrate; (iv) optionally, applying a polymer solution, preferably in at least one organic solvent; (v) applying a repair patch of a polymer onto at least a part of the composite surface; (vi) applying heat so that the repair patch of a polymer tape melts and covers the damaged area, thereby forming a protection layer or applying a repair solution, preferably in at least one organic solvent, so that the repair patch of a polymer tape at least partially dissolves and covers the damaged area.
Research Progress on Interlaminar Failure Behavior of Fiber Metal Laminates
Research Progress on Interlaminar Failure Behavior of Fiber Metal Laminates
Fiber metal laminate (FML) is a kind of lightweight material with excellent mechanical properties combining advantages of metal laminates and fiber reinforced composites. It has been widely used in the aerospace and transportation fields and is especially used as structural material such as aircraft skins, wings, and tails. However, under complex service conditions, interlaminar failure in FMLs greatly reduced mechanical properties of the material, even leading to serious economic and safety disasters. The failure and destruction of important structural parts of aircraft and other manned transportation vehicles are extremely unsafe for people. Therefore, it is of great significance to summarize the interlaminar failure behavior of FMLs and find ways to avoid these defects. This review paper is a collection of various researches done by many groups, which systematically discuss the interlaminar failure behaviors and their control methods of FMLs. The application status of several common FMLs in aircraft structures was given. The common interlaminar failure modes of FMLs and the testing and evaluation methods of interlaminar properties were stated. The failure mechanisms and the corresponding control methods were analyzed. Finally, the future developments of FMLs were also discussed by the authors. Through this review article, readers can obtain new research progress about the control method, the mechanism and future development on the failure behavior of FMLs in a more efficient way.
Fiber metal laminate (FML) is a kind of lightweight material with excellent mechanical properties combining advantages of metal laminates and fiber reinforced composites. It has been widely used in the aerospace and transportation fields and is especially used as structural material such as aircraft skins, wings, and tails. However, under complex service conditions, interlaminar failure in FMLs greatly reduced mechanical properties of the material, even leading to serious economic and safety disasters. The failure and destruction of important structural parts of aircraft and other manned transportation vehicles are extremely unsafe for people. Therefore, it is of great significance to summarize the interlaminar failure behavior of FMLs and find ways to avoid these defects. This review paper is a collection of various researches done by many groups, which systematically discuss the interlaminar failure behaviors and their control methods of FMLs. The application status of several common FMLs in aircraft structures was given. The common interlaminar failure modes of FMLs and the testing and evaluation methods of interlaminar properties were stated. The failure mechanisms and the corresponding control methods were analyzed. Finally, the future developments of FMLs were also discussed by the authors. Through this review article, readers can obtain new research progress about the control method, the mechanism and future development on the failure behavior of FMLs in a more efficient way.
4 mars 2020
[2002.12201] Non-destructive testing and evaluation of composite materials/structures: A state-of-the-art review
[2002.12201] Non-destructive testing and evaluation of composite materials/structures: A state-of-the-art review
Composite materials/structures are advancing in product efficiency, cost-effectiveness and the development of superior specific properties. There are increasing demands in their applications to load-carrying structures in aerospace, wind turbines, transportation, and medical equipment, etc. Thus robust and reliable non-destructive testing (NDT) of composites is essential to reduce safety concerns and maintenance costs. There have been various NDT methods built upon different principles for quality assurance during the whole lifecycle of a composite product. This paper reviews the most established NDT techniques for detection and evaluation of defects/damage evolution in composites. These include acoustic emission, ultrasonic testing, infrared thermography, terahertz testing, shearography, digital image correlation, as well as X-ray and neutron imaging. For each NDT technique, we cover a brief historical background, principles, standard practices, equipment and facilities used for composite research. We also compare and discuss their benefits and limitations, and further summarise their capabilities and applications to composite structures. Each NDT technique has its own potential and rarely achieves a full-scale diagnosis of structural integrity. Future development of NDT techniques for composites will be directed towards intelligent and automated inspection systems with high accuracy and efficient data processing capabilities.
Composite materials/structures are advancing in product efficiency, cost-effectiveness and the development of superior specific properties. There are increasing demands in their applications to load-carrying structures in aerospace, wind turbines, transportation, and medical equipment, etc. Thus robust and reliable non-destructive testing (NDT) of composites is essential to reduce safety concerns and maintenance costs. There have been various NDT methods built upon different principles for quality assurance during the whole lifecycle of a composite product. This paper reviews the most established NDT techniques for detection and evaluation of defects/damage evolution in composites. These include acoustic emission, ultrasonic testing, infrared thermography, terahertz testing, shearography, digital image correlation, as well as X-ray and neutron imaging. For each NDT technique, we cover a brief historical background, principles, standard practices, equipment and facilities used for composite research. We also compare and discuss their benefits and limitations, and further summarise their capabilities and applications to composite structures. Each NDT technique has its own potential and rarely achieves a full-scale diagnosis of structural integrity. Future development of NDT techniques for composites will be directed towards intelligent and automated inspection systems with high accuracy and efficient data processing capabilities.
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