The Experts below are selected from a list of 255 Experts worldwide ranked by ideXlab platform

Christian Fraboul - One of the best experts on this subject based on the ideXlab platform.

  • A Probabilistic analysis of end-to-end delays on an AFDX avionic network
    IEEE Transactions on Industrial Informatics, 2009
    Co-Authors: Jean-luc Scharbarg, Fŕd́ric Ridouard, Christian Fraboul
    Abstract:

    AFDX (Avionics Full DupleX Switched Ethernet, ARINC 664) developed\nfor the Airbus A380 represents a major upgrade in both bandwidth\nand capability. Its reliance on Ethernet technology helps to lower\nsome implementation costs, but guaranteed service presents challenges\nfor system designers. An analysis of end-to-end transfer delays through\nthe network is required in order to determine upper bounds. In this\npaper, we propose to compute probabilistic upper bounds for end-to-end\ndelays on avionic flows. Such upper bounds can be exceeded with a\ngiven probability p, and are relevant in the context of avionics,\nwhere functions are designed to give accurate results even if they\nmiss some frames. The stochastic network calculus approach analytically\ndetermines a probabilistic upper bound, whereas the simulation approach\ngives an experimental upper bound. The former may be used for new\ncertification needs since it assures that the probability of exceeding\nthe computed upper bound is not greater than p. The latter closely\napproximates actual network behavior and can help to give some idea\nof the pessimism of the stochastic network calculus upper bound.\nThe two approaches have been developed in the context of an industrial\nAFDX network configuration.

  • stochastic network calculus for end to end delays distribution evaluation on an avionics switched ethernet
    International Conference on Industrial Informatics, 2007
    Co-Authors: Fŕd́ric Ridouard, Jean-luc Scharbarg, Christian Fraboul
    Abstract:

    AFDX (avionics full duplex switched Ethernet, AR-INC 664) used for modern aircraft such as Airbus A380 represents a major upgrade in both bandwidth and capability for aircraft data networks. Its reliance on Ethernet technology helps to lower some of the implementation costs, though the requirement for guaranteed service does present challenges to system designers. Thus, the problem is to prove that no frame will be lost by the network (no switch queue will overflow) and to evaluate the end-to-end transfer delay through the network. Several approaches have been proposed for this evaluation. Deterministic network calculus gives a guaranteed upper bound on end-to-end delays, while simulation produces more accurate results on a given set of scenarios. In this paper, we propose a stochastic network calculus approach in order to evaluate the distribution of end-to-end delays. We evaluate the pessimism of the results on some typical AFDX flows, as described by virtual links.

  • Simulation for end-to-end delays distribution on a switched Ethernet
    IEEE International Conference on Emerging Technologies and Factory Automation, ETFA, 2007
    Co-Authors: Jean-luc Scharbarg, Christian Fraboul
    Abstract:

    AFDX (Avionics Full Duplex Switched Ethernet, ARINC 664) used for modern aircraft such as Airbus A380 represents a major upgrade in both bandwidth and capability for aircraft data networks. Its reliance on Ethernet technology helps to lower some of the implementation costs, though the requirement for guaranteed service does present challenges to system designers. Thus, the problem is to prove that no frame will be lost by the network (no switch queue will overflow) and to evaluate the end-to-end transfer delay through the network. Several approaches have been proposed for this evaluation. Network calculus gives a guaranteed upper bound on end-to-end delays, while simulation produces more accurate results on a given set of scenarios. Main problem of simulation is to find a representative subset among the huge number of possible scenarios. In this paper, we propose an original and promising approach to drastically reduce the number of possible scenarios. We illustrate this approach on a realistic industrial network configuration.

  • Modelling and simulation of an avionics full duplex Switched Ethernet
    Proceedings - Advanced Industrial Conference on Telecommunications/Service Assurance with Partial and Intermittent Resources Conference/E-Learning on , 2005
    Co-Authors: Hussein Charara, Christian Fraboul
    Abstract:

    Architectures of embedded avionics networks, such as that of the future Airbus A380, currently know important evolutions. This is principally due to the increase in the complexity of the embedded systems, in terms of the rise in the number of integrated functions and their connectivity. The evolution in the technologies of data transmission local area networks makes it possible to convey new answers to airframe manufacturers. In particular, switched Ethernet technologies are being implemented as an avionics architecture, even if the non-deterministic character of certain networks must be compensated by strong assumptions. The paper presents a simulation model for dimensioning an avionics full duplex switched Ethernet network (AFDX) and for studying the performance of this network. Comparison with other deterministic studies which use network calculus is also performed.

Cano Miguel - One of the best experts on this subject based on the ideXlab platform.

  • Contribution à l'étude du comportement mécanique d'un ruban de préimprégné dans le procédé de placement de fibres : analyse expérimentale et modélisation
    2010
    Co-Authors: Cano Miguel
    Abstract:

    Une grande partie de la structure des avions modernes est fabriquée à partir des dernières générations de matériaux composites. Le principal défi des constructeurs d’avions réside dans la taille importante des pièces en composites. D’où la nécessité de développer de nouvelles technologies de fabrication telle que la dépose automatique de préimprégné. La qualité des pièces fabriquées dépend de nombreux facteurs dont notamment la maîtrise de la rhéologie de la résine du préimprégné. Cette dernière évolue fortement avec les conditions environnementales et les conditions de fabrication. Elle détermine pour partie, les instabilités de la matière particulièrement le long des trajectoires curvilignes. Ces instabilités, qui se présentent sous forme de cloques, engendrent après cuisson des pièces avec des défauts de repliement des couches dans les stratifiés. L’objectif principal de cette thèse de doctorat est l’étude du comportement mécanique d’un ruban de préimprégné prenant en compte la rhéologie de la matière ainsi que sa pégosité dans le but de mieux comprendre les conditions d’apparition des cloques en trajectoire curviligne. Une partie de mes travaux est consacrée à la caractérisation des propriétés physico-chimiques et mécaniques de la matière. Une seconde partie, complémentaire à la première, est dédiée au développement d’un modèle de comportement mécanique d’une plaque sur fondation élastique représentant le ruban de préimprégné et soumise à une rotation imposée. La méthode de Ritz a été utilisée pour l'obtention de solutions explicites des charges critiques de flambement. Il a été montré que les plus faibles rayons de courbure sans formation de cloques en trajectoire curviligne dans le plan sont obtenus avec un faible écrasement du rouleau et un niveau de collant élevé.The evolution of composite materials in aerospace has been spectacular over the last thirty years. The main advantage provided by composites is weight gain compared to other materials. However, new aluminum lithium alloys may slow this trend because of their specific properties and exceptional manufacturing costs lower than those of composites. Much parts of the structure of the A380 are made from the latest generation of composite materials with organic matrix. The Airbus A380 is the first plane of the manufacturer composed by a center wing box made by composite reinforced with carbon fibers and organic matrix. And like the devices that preceded it, the center wing box, rudder, horizontal stabilizer and the elevators were designed with composites reinforced with carbon fibers and organic matrix. But the main challenge with the new aircraft is the size of parts ; the size of the horizontal stabilizer of the A380 for example, is similar to the wing of the A310. Hence the need to develop the intensive use of automatic prepreg lay up technology. The use of semi-finished prepregs for the manufacture of parts allows standardizing production. Indeed, these products exhibit with the desired rate of reinforcement on the final parts, all the delicate operations of pumping excess resin during the implementation of parts, as the case in the RTM process (Resin Transfer Molding) are eliminated. The quality of parts produced using automatic lay up depends on many factors including the accuracy of trajectory lay up, the control of rheology of the resin contained in the prepreg and behavior at the interface of the material and tooling. The rheology of the resin is changing considerably with environmental conditions (temperature, humidity) and processing conditions (speed of removal, compaction strength). It determines in part and in combination with the tackiness of the prepreg, the instabilities of the material particularly along curved trajectories. In curvilinear lay up, the rotation of the tow placement head imposes to this portion of slit tape, a curvature generating a circular bending phenomenon.The outer portion of the tape is then stretched while the inside is compressed. When the radius of curvature of the tow placement head is low, the result is a phenomenon of local buckling of the slit tape. The corresponding layer waviness (See figure 1) is visible after the passage of the roller so instantly or delayed, depending on the conditions of lay up (speed lay up,compaction strength, temperature, humidity) and the tackiness of the material. Thus, the formation of the layer waviness is a local phenomenon that appears in the material between the tow placement head and tools. It is this area of the material defined by the form of plate, and the extent of which depends on the compaction strength and flexibility of the roller which will be the model proposed in this communication. It is supposed that this plate is based on elastic foundation in order to reflect the tack of the material. The formation mechanism of ply waviness is very few studied and remains unclear since these defects appear at different steps in the manufacturing process. Some studies recommend, without justification, to not exceed some radius of curvature to avoid buckling [1]. Interactions between tooling and material in relation with lay up conditions were studied [2]. In this paper we study the mechanical behavior of a slit tape taking into account the rheology of the material so that his tack in order to better understand the conditions of appearance of layer waviness during circular trajectories. At first, we will present some results from the identification of physico-chemical and mechanical properties of prepreg carbon / epoxy and then we will explain the evolutions observed. A second part, complements the first,will be dedicated to the development of a model of mechanical behavior of a plate based onelastic foundation, representing the slit tape which is subjected to a rotation imposed. The mechanical model of the slit tape will be based on the theory of plate under the hypotheses of Kirchhoff-Love and Von-Karman. Determining the critical buckling load is carried by the Ritz method. The simulation results using different boundary conditions will be analyzed and compared to real cases

  • Contribution à l'étude du comportement mécanique d'un ruban de préimprégné dans le procédé de placement de fibres (analyse expérimentale et modélisation)
    2010
    Co-Authors: Cano Miguel, Beakou Alexis
    Abstract:

    Une grande partie de la structure des avions modernes est fabriquée à partir des dernières générations de matériaux composites. Le principal défi des constructeurs d avions réside dans la taille importante des pièces en composites. D où la nécessité de développer de nouvelles technologies de fabrication telle que la dépose automatique de préimprégné. La qualité des pièces fabriquées dépend de nombreux facteurs dont notamment la maîtrise de la rhéologie de la résine du préimprégné. Cette dernière évolue fortement avec les conditions environnementales et les conditions de fabrication. Elle détermine pour partie, les instabilités de la matière particulièrement le long des trajectoires curvilignes. Ces instabilités, qui se présentent sous forme de cloques, engendrent après cuisson des pièces avec des défauts de repliement des couches dans les stratifiés. L objectif principal de cette thèse de doctorat est l étude du comportement mécanique d un ruban de préimprégné prenant en compte la rhéologie de la matière ainsi que sa pégosité dans le but de mieux comprendre les conditions d apparition des cloques en trajectoire curviligne. Une partie de mes travaux est consacrée à la caractérisation des propriétés physico-chimiques et mécaniques de la matière. Une seconde partie, complémentaire à la première, est dédiée au développement d un modèle de comportement mécanique d une plaque sur fondation élastique représentant le ruban de préimprégné et soumise à une rotation imposée. La méthode de Ritz a été utilisée pour l'obtention de solutions explicites des charges critiques de flambement. Il a été montré que les plus faibles rayons de courbure sans formation de cloques en trajectoire curviligne dans le plan sont obtenus avec un faible écrasement du rouleau et un niveau de collant élevé.The evolution of composite materials in aerospace has been spectacular over the last thirty years. The main advantage provided by composites is weight gain compared to other materials. However, new aluminum lithium alloys may slow this trend because of their specific properties and exceptional manufacturing costs lower than those of composites. Much parts of the structure of the A380 are made from the latest generation of composite materials with organic matrix. The Airbus A380 is the first plane of the manufacturer composed by a center wing box made by composite reinforced with carbon fibers and organic matrix. And like the devices that preceded it, the center wing box, rudder, horizontal stabilizer and the elevators were designed with composites reinforced with carbon fibers and organic matrix. But the main challenge with the new aircraft is the size of parts ; the size of the horizontal stabilizer of the A380 for example, is similar to the wing of the A310. Hence the need to develop the intensive use of automatic prepreg lay up technology. The use of semi-finished prepregs for the manufacture of parts allows standardizing production. Indeed, these products exhibit with the desired rate of reinforcement on the final parts, all the delicate operations of pumping excess resin during the implementation of parts, as the case in the RTM process (Resin Transfer Molding) are eliminated. The quality of parts produced using automatic lay up depends on many factors including the accuracy of trajectory lay up, the control of rheology of the resin contained in the prepreg and behavior at the interface of the material and tooling. The rheology of the resin is changing considerably with environmental conditions (temperature, humidity) and processing conditions (speed of removal, compaction strength). It determines in part and in combination with the tackiness of the prepreg, the instabilities of the material particularly along curved trajectories. In curvilinear lay up, the rotation of the tow placement head imposes to this portion of slit tape, a curvature generating a circular bending phenomenon.The outer portion of the tape is then stretched while the inside is compressed. When the radius of curvature of the tow placement head is low, the result is a phenomenon of local buckling of the slit tape. The corresponding layer waviness (See figure 1) is visible after the passage of the roller so instantly or delayed, depending on the conditions of lay up (speed lay up,compaction strength, temperature, humidity) and the tackiness of the material. Thus, the formation of the layer waviness is a local phenomenon that appears in the material between the tow placement head and tools. It is this area of the material defined by the form of plate, and the extent of which depends on the compaction strength and flexibility of the roller which will be the model proposed in this communication. It is supposed that this plate is based on elastic foundation in order to reflect the tack of the material. The formation mechanism of ply waviness is very few studied and remains unclear since these defects appear at different steps in the manufacturing process. Some studies recommend, without justification, to not exceed some radius of curvature to avoid buckling [1]. Interactions between tooling and material in relation with lay up conditions were studied [2]. In this paper we study the mechanical behavior of a slit tape taking into account the rheology of the material so that his tack in order to better understand the conditions of appearance of layer waviness during circular trajectories. At first, we will present some results from the identification of physico-chemical and mechanical properties of prepreg carbon / epoxy and then we will explain the evolutions observed. A second part, complements the first,will be dedicated to the development of a model of mechanical behavior of a plate based onelastic foundation, representing the slit tape which is subjected to a rotation imposed. The mechanical model of the slit tape will be based on the theory of plate under the hypotheses of Kirchhoff-Love and Von-Karman. Determining the critical buckling load is carried by the Ritz method. The simulation results using different boundary conditions will be analyzed and compared to real cases.CLERMONT FD-Bib.électronique (631139902) / SudocSudocFranceF

Beakou Alexis - One of the best experts on this subject based on the ideXlab platform.

  • Contribution à l'étude du comportement mécanique d'un ruban de préimprégné dans le procédé de placement de fibres (analyse expérimentale et modélisation)
    2010
    Co-Authors: Cano Miguel, Beakou Alexis
    Abstract:

    Une grande partie de la structure des avions modernes est fabriquée à partir des dernières générations de matériaux composites. Le principal défi des constructeurs d avions réside dans la taille importante des pièces en composites. D où la nécessité de développer de nouvelles technologies de fabrication telle que la dépose automatique de préimprégné. La qualité des pièces fabriquées dépend de nombreux facteurs dont notamment la maîtrise de la rhéologie de la résine du préimprégné. Cette dernière évolue fortement avec les conditions environnementales et les conditions de fabrication. Elle détermine pour partie, les instabilités de la matière particulièrement le long des trajectoires curvilignes. Ces instabilités, qui se présentent sous forme de cloques, engendrent après cuisson des pièces avec des défauts de repliement des couches dans les stratifiés. L objectif principal de cette thèse de doctorat est l étude du comportement mécanique d un ruban de préimprégné prenant en compte la rhéologie de la matière ainsi que sa pégosité dans le but de mieux comprendre les conditions d apparition des cloques en trajectoire curviligne. Une partie de mes travaux est consacrée à la caractérisation des propriétés physico-chimiques et mécaniques de la matière. Une seconde partie, complémentaire à la première, est dédiée au développement d un modèle de comportement mécanique d une plaque sur fondation élastique représentant le ruban de préimprégné et soumise à une rotation imposée. La méthode de Ritz a été utilisée pour l'obtention de solutions explicites des charges critiques de flambement. Il a été montré que les plus faibles rayons de courbure sans formation de cloques en trajectoire curviligne dans le plan sont obtenus avec un faible écrasement du rouleau et un niveau de collant élevé.The evolution of composite materials in aerospace has been spectacular over the last thirty years. The main advantage provided by composites is weight gain compared to other materials. However, new aluminum lithium alloys may slow this trend because of their specific properties and exceptional manufacturing costs lower than those of composites. Much parts of the structure of the A380 are made from the latest generation of composite materials with organic matrix. The Airbus A380 is the first plane of the manufacturer composed by a center wing box made by composite reinforced with carbon fibers and organic matrix. And like the devices that preceded it, the center wing box, rudder, horizontal stabilizer and the elevators were designed with composites reinforced with carbon fibers and organic matrix. But the main challenge with the new aircraft is the size of parts ; the size of the horizontal stabilizer of the A380 for example, is similar to the wing of the A310. Hence the need to develop the intensive use of automatic prepreg lay up technology. The use of semi-finished prepregs for the manufacture of parts allows standardizing production. Indeed, these products exhibit with the desired rate of reinforcement on the final parts, all the delicate operations of pumping excess resin during the implementation of parts, as the case in the RTM process (Resin Transfer Molding) are eliminated. The quality of parts produced using automatic lay up depends on many factors including the accuracy of trajectory lay up, the control of rheology of the resin contained in the prepreg and behavior at the interface of the material and tooling. The rheology of the resin is changing considerably with environmental conditions (temperature, humidity) and processing conditions (speed of removal, compaction strength). It determines in part and in combination with the tackiness of the prepreg, the instabilities of the material particularly along curved trajectories. In curvilinear lay up, the rotation of the tow placement head imposes to this portion of slit tape, a curvature generating a circular bending phenomenon.The outer portion of the tape is then stretched while the inside is compressed. When the radius of curvature of the tow placement head is low, the result is a phenomenon of local buckling of the slit tape. The corresponding layer waviness (See figure 1) is visible after the passage of the roller so instantly or delayed, depending on the conditions of lay up (speed lay up,compaction strength, temperature, humidity) and the tackiness of the material. Thus, the formation of the layer waviness is a local phenomenon that appears in the material between the tow placement head and tools. It is this area of the material defined by the form of plate, and the extent of which depends on the compaction strength and flexibility of the roller which will be the model proposed in this communication. It is supposed that this plate is based on elastic foundation in order to reflect the tack of the material. The formation mechanism of ply waviness is very few studied and remains unclear since these defects appear at different steps in the manufacturing process. Some studies recommend, without justification, to not exceed some radius of curvature to avoid buckling [1]. Interactions between tooling and material in relation with lay up conditions were studied [2]. In this paper we study the mechanical behavior of a slit tape taking into account the rheology of the material so that his tack in order to better understand the conditions of appearance of layer waviness during circular trajectories. At first, we will present some results from the identification of physico-chemical and mechanical properties of prepreg carbon / epoxy and then we will explain the evolutions observed. A second part, complements the first,will be dedicated to the development of a model of mechanical behavior of a plate based onelastic foundation, representing the slit tape which is subjected to a rotation imposed. The mechanical model of the slit tape will be based on the theory of plate under the hypotheses of Kirchhoff-Love and Von-Karman. Determining the critical buckling load is carried by the Ritz method. The simulation results using different boundary conditions will be analyzed and compared to real cases.CLERMONT FD-Bib.électronique (631139902) / SudocSudocFranceF

Jean-luc Scharbarg - One of the best experts on this subject based on the ideXlab platform.

  • A Probabilistic analysis of end-to-end delays on an AFDX avionic network
    IEEE Transactions on Industrial Informatics, 2009
    Co-Authors: Jean-luc Scharbarg, Fŕd́ric Ridouard, Christian Fraboul
    Abstract:

    AFDX (Avionics Full DupleX Switched Ethernet, ARINC 664) developed\nfor the Airbus A380 represents a major upgrade in both bandwidth\nand capability. Its reliance on Ethernet technology helps to lower\nsome implementation costs, but guaranteed service presents challenges\nfor system designers. An analysis of end-to-end transfer delays through\nthe network is required in order to determine upper bounds. In this\npaper, we propose to compute probabilistic upper bounds for end-to-end\ndelays on avionic flows. Such upper bounds can be exceeded with a\ngiven probability p, and are relevant in the context of avionics,\nwhere functions are designed to give accurate results even if they\nmiss some frames. The stochastic network calculus approach analytically\ndetermines a probabilistic upper bound, whereas the simulation approach\ngives an experimental upper bound. The former may be used for new\ncertification needs since it assures that the probability of exceeding\nthe computed upper bound is not greater than p. The latter closely\napproximates actual network behavior and can help to give some idea\nof the pessimism of the stochastic network calculus upper bound.\nThe two approaches have been developed in the context of an industrial\nAFDX network configuration.

  • stochastic network calculus for end to end delays distribution evaluation on an avionics switched ethernet
    International Conference on Industrial Informatics, 2007
    Co-Authors: Fŕd́ric Ridouard, Jean-luc Scharbarg, Christian Fraboul
    Abstract:

    AFDX (avionics full duplex switched Ethernet, AR-INC 664) used for modern aircraft such as Airbus A380 represents a major upgrade in both bandwidth and capability for aircraft data networks. Its reliance on Ethernet technology helps to lower some of the implementation costs, though the requirement for guaranteed service does present challenges to system designers. Thus, the problem is to prove that no frame will be lost by the network (no switch queue will overflow) and to evaluate the end-to-end transfer delay through the network. Several approaches have been proposed for this evaluation. Deterministic network calculus gives a guaranteed upper bound on end-to-end delays, while simulation produces more accurate results on a given set of scenarios. In this paper, we propose a stochastic network calculus approach in order to evaluate the distribution of end-to-end delays. We evaluate the pessimism of the results on some typical AFDX flows, as described by virtual links.

  • Simulation for end-to-end delays distribution on a switched Ethernet
    IEEE International Conference on Emerging Technologies and Factory Automation, ETFA, 2007
    Co-Authors: Jean-luc Scharbarg, Christian Fraboul
    Abstract:

    AFDX (Avionics Full Duplex Switched Ethernet, ARINC 664) used for modern aircraft such as Airbus A380 represents a major upgrade in both bandwidth and capability for aircraft data networks. Its reliance on Ethernet technology helps to lower some of the implementation costs, though the requirement for guaranteed service does present challenges to system designers. Thus, the problem is to prove that no frame will be lost by the network (no switch queue will overflow) and to evaluate the end-to-end transfer delay through the network. Several approaches have been proposed for this evaluation. Network calculus gives a guaranteed upper bound on end-to-end delays, while simulation produces more accurate results on a given set of scenarios. Main problem of simulation is to find a representative subset among the huge number of possible scenarios. In this paper, we propose an original and promising approach to drastically reduce the number of possible scenarios. We illustrate this approach on a realistic industrial network configuration.

Koklu Ugur - One of the best experts on this subject based on the ideXlab platform.

  • Microstructural investigation and hole quality evaluation in S2/FM94 glass-fibre composites under dry and cryogenic conditions
    'SAGE Publications', 2021
    Co-Authors: Giasin Khaled, Barouni Antigoni, Dhakal, Hom Nath, Featherson Carol, Morkavuk Sezer, Zitoune Redouane, Koklu Ugur
    Abstract:

    International audienceS2/FM94 glass fibre reinforced epoxy is an aerospace-grade composite currently bonded with aluminium alloys and installed in parts of the Airbus A380 fuselage. In addition to its abrasive and hard nature, S2/FM94 glass fibre is sensitive to thermal effects developed during the drilling process, and therefore using coolants becomes necessary. However, conventional oil and water-based coolants are not suitable for drilling of composites. Cryogenic coolants on the other hand are an attractive choice for machining composites and are environmentally friendly. In this study, a new environmentally friendly cryogenic cooling technique in a liquid nitrogen bath was used for the drilling of S2/FM94 glass fibre reinforced epoxy composite. The aim was to investigate the effect of drilling parameters and cryogenic cooling on cutting forces, surface roughness, hardness and delamination factor at hole entry and exit sides. The workpiece was drilled within a cryogenic bath. In this way, both cryogenic workpiece cooling and tool cooling were obtained. In addition, the drill geometry is fixed and only the cutting parameters (i.e. spindle speed and the feed rate) are varied under dry and cryogenic conditions. The results indicate that the spindle speed and cryogenic cooling had the most significant influence on the cutting forces and surface roughness parameters (R a and R z ), while the use of cryogenic cooling had the most significant influence on increasing the hardness and size of delamination at entry and exit sides of the holes

  • Microstructural investigation and hole quality evaluation in S2/FM94 glass-fibre composites under dry and cryogenic conditions
    'SAGE Publications', 2020
    Co-Authors: Giasin Khaled, Barouni Antigoni, Dhakal, Hom Nath, Featherson Carol, Redouane Zitoune, Morkavuk Sezer, Koklu Ugur
    Abstract:

    S2/FM94 glass fibre reinforced epoxy is an aerospace-grade composite currently bonded with aluminium alloys and installed in parts of the Airbus A380 fuselage. In addition to its abrasive and hard nature, S2/FM94 glass fibre is sensitive to thermal effects developed during the drilling process, and therefore using coolants becomes necessary. However, conventional oil and water-based coolants are not suitable for drilling of composites. Cryogenic coolants on the other hand are an attractive choice for machining composites and are environmentally friendly. In this study, a new environmentally friendly cryogenic cooling technique in a liquid nitrogen bath was used for the drilling of S2/FM94 glass fibre reinforced epoxy composite. The aim was to investigate the effect of drilling parameters and cryogenic cooling on cutting forces, surface roughness, hardness and delamination factor at hole entry and exit sides. The workpiece was drilled within a cryogenic bath. In this way, both cryogenic workpiece cooling and tool cooling were obtained. In addition, the drill geometry is fixed and only the cutting parameters (i.e. spindle speed and the feed rate) are varied under dry and cryogenic conditions. The results indicate that the spindle speed and cryogenic cooling had the most significant influence on the cutting forces and surface roughness parameters (Ra and Rz), while the use of cryogenic cooling had the most significant influence on increasing the hardness and size of delamination at entry and exit sides of the holes