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The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.Wed, 27 May 2020 00:14:26 GMT2020-05-27T00:14:26ZA new paradigm for the optimum design of variable angle tow laminates
http://hdl.handle.net/10985/11387
A new paradigm for the optimum design of variable angle tow laminates
MONTEMURRO, Marco; CATAPANO, Anita
In this work the authors propose a new paradigm for the optimum design of variable angle tow (VAT) composites. They propose a generalisation of a multi-scale two-level (MS2L) optimisation strategy already employed to solve optimisation problems of anisotropic structures characterised by a constant stiffness distribution. In the framework of the MS2L methodology, the design problem is split into two sub-problems. At the first step of the strategy the goal is to determine the optimum distribution of the laminate stiffness properties over the structure, while the second step aims at retrieving the optimum fibres-path in each layer meeting all the requirements provided by the problem at hand. The MS2L strategy relies on: a) the polar formalism for describing the behaviour of the VAT laminate, b) the iso-geometric surfaces for describing the spatial variation of the stiffness properties and c) an hybrid optimisation tool (genetic and gradient-based algorithms) to perform the solution search. The effectiveness of the MS2L strategy is proven through a numerical example on the maximisation of the first buckling factor of a VAT plate subject to both mechanical and manufacturability constraints.
Fri, 01 Jan 2016 00:00:00 GMThttp://hdl.handle.net/10985/113872016-01-01T00:00:00ZMONTEMURRO, MarcoCATAPANO, AnitaIn this work the authors propose a new paradigm for the optimum design of variable angle tow (VAT) composites. They propose a generalisation of a multi-scale two-level (MS2L) optimisation strategy already employed to solve optimisation problems of anisotropic structures characterised by a constant stiffness distribution. In the framework of the MS2L methodology, the design problem is split into two sub-problems. At the first step of the strategy the goal is to determine the optimum distribution of the laminate stiffness properties over the structure, while the second step aims at retrieving the optimum fibres-path in each layer meeting all the requirements provided by the problem at hand. The MS2L strategy relies on: a) the polar formalism for describing the behaviour of the VAT laminate, b) the iso-geometric surfaces for describing the spatial variation of the stiffness properties and c) an hybrid optimisation tool (genetic and gradient-based algorithms) to perform the solution search. The effectiveness of the MS2L strategy is proven through a numerical example on the maximisation of the first buckling factor of a VAT plate subject to both mechanical and manufacturability constraints.Simultaneous size/ material optimisation and accurate analysis of composite stiffened panels
http://hdl.handle.net/10985/12938
Simultaneous size/ material optimisation and accurate analysis of composite stiffened panels
MONTEMURRO, Marco; PAGANI, Alfonso; FIORDILINO, Giacinto Alberto; PAILHES, Jérôme; CARRERA, Erasmo
this work deals with the problem of the least-weight design of a composite stiffened panel. The design problem is stated as a constrained non-linear programming problem (CNLPP). Optimisation constraints of different nature are considered: mechanical constraints on the admissible material properties of the laminates as well as on the global buckling load of the panel, geometrical and manufacturability constraints on the geometric design variables of both the skin and the stiffeners. To face such a problem a multi-scale two-level (MS2L) design methodology is proposed. The MS2L design method aims at optimising simultaneously both the geometrical and the material parameters for the skin and the stiffeners at each characteristic scale (meso and macro scales). The MS2L optimisation strategy relies on the one hand on the utilisation of the polar parameters (in the framework of the equivalent single layer theories) for describing the macroscopic behaviour of each laminate composing the panel (both skin and stiffeners) and on the other hand on a special hybrid algorithm (genetic algorithm + gradient-based algorithm) in order to perform the solution search for the problem at hand. In this background, the design problem is split into two different (but related) optimisation problems. At the first level (macroscopic scale) the goal is to find the optimum value of the geometric and material (i.e. the polar parameters) design variables of the panel minimising its mass and meeting (simultaneously) all the requirements provided by the technical specification (i.e. the optimisation constraints) for the problem at hand. The second-level problem focuses on the laminate mesoscopic scale (i.e. the ply-level). Here the goal is the determination of at least one stacking-sequence (for each laminate composing the panel) meeting the optimum value of both the material and geometrical design variables provided by the first-level problem. The effectiveness of the new, non-classical configurations will be verified a posteriori through a refined finite element model of the stiffened panel making use of elements with different kinematics and accuracy (in a global-local sense) in the framework of the Carrera Unified Formulation (CUF).
Sun, 01 Jan 2017 00:00:00 GMThttp://hdl.handle.net/10985/129382017-01-01T00:00:00ZMONTEMURRO, MarcoPAGANI, AlfonsoFIORDILINO, Giacinto AlbertoPAILHES, JérômeCARRERA, Erasmothis work deals with the problem of the least-weight design of a composite stiffened panel. The design problem is stated as a constrained non-linear programming problem (CNLPP). Optimisation constraints of different nature are considered: mechanical constraints on the admissible material properties of the laminates as well as on the global buckling load of the panel, geometrical and manufacturability constraints on the geometric design variables of both the skin and the stiffeners. To face such a problem a multi-scale two-level (MS2L) design methodology is proposed. The MS2L design method aims at optimising simultaneously both the geometrical and the material parameters for the skin and the stiffeners at each characteristic scale (meso and macro scales). The MS2L optimisation strategy relies on the one hand on the utilisation of the polar parameters (in the framework of the equivalent single layer theories) for describing the macroscopic behaviour of each laminate composing the panel (both skin and stiffeners) and on the other hand on a special hybrid algorithm (genetic algorithm + gradient-based algorithm) in order to perform the solution search for the problem at hand. In this background, the design problem is split into two different (but related) optimisation problems. At the first level (macroscopic scale) the goal is to find the optimum value of the geometric and material (i.e. the polar parameters) design variables of the panel minimising its mass and meeting (simultaneously) all the requirements provided by the technical specification (i.e. the optimisation constraints) for the problem at hand. The second-level problem focuses on the laminate mesoscopic scale (i.e. the ply-level). Here the goal is the determination of at least one stacking-sequence (for each laminate composing the panel) meeting the optimum value of both the material and geometrical design variables provided by the first-level problem. The effectiveness of the new, non-classical configurations will be verified a posteriori through a refined finite element model of the stiffened panel making use of elements with different kinematics and accuracy (in a global-local sense) in the framework of the Carrera Unified Formulation (CUF).Multi-scale characterisation of material properties of composite fabrics through modal tests
http://hdl.handle.net/10985/12540
Multi-scale characterisation of material properties of composite fabrics through modal tests
MONTEMURRO, Marco; DAU, Frédéric; GUILLAUMAT, Laurent; CAPPELLI, Lorenzo
One of the main issues of composite materials is related to the difficulty of characterising the material properties at mesoscopic and microscopic scales. Classical mechanical tests are not able to provide the full set of 3D properties : these tests can provide only the in-plane elastic properties of the constitutive lamina. Therefore, to go beyond the main restrictions imposed by standard destructive tests, this work deals with the problem of characterising the material properties of a multilayer composite plate, through a non-destructive modal test performed at the macro-scale : a multi-scale identification strategy (MSIS) is proposed. The MSIS aims at identifying the constitutive properties by exploiting the information restrained in the composite macroscopic dynamical response. The MSIS relies on the strain energy homogenisation technique of periodic media and on a gradient-based algorithm to perform the solution search. The identification problem is stated as a constrained inverse problem, where the objective function depends upon both experimental and numerical natural frequencies of the specimen. In this background, the optimisation variables are both geometrical and material properties of the constitutive phases composing the representative volume element. The effectiveness of the approach will be proven through a campaign of tests conducted on multilayer composites.
Sun, 01 Jan 2017 00:00:00 GMThttp://hdl.handle.net/10985/125402017-01-01T00:00:00ZMONTEMURRO, MarcoDAU, FrédéricGUILLAUMAT, LaurentCAPPELLI, LorenzoOne of the main issues of composite materials is related to the difficulty of characterising the material properties at mesoscopic and microscopic scales. Classical mechanical tests are not able to provide the full set of 3D properties : these tests can provide only the in-plane elastic properties of the constitutive lamina. Therefore, to go beyond the main restrictions imposed by standard destructive tests, this work deals with the problem of characterising the material properties of a multilayer composite plate, through a non-destructive modal test performed at the macro-scale : a multi-scale identification strategy (MSIS) is proposed. The MSIS aims at identifying the constitutive properties by exploiting the information restrained in the composite macroscopic dynamical response. The MSIS relies on the strain energy homogenisation technique of periodic media and on a gradient-based algorithm to perform the solution search. The identification problem is stated as a constrained inverse problem, where the objective function depends upon both experimental and numerical natural frequencies of the specimen. In this background, the optimisation variables are both geometrical and material properties of the constitutive phases composing the representative volume element. The effectiveness of the approach will be proven through a campaign of tests conducted on multilayer composites.A multi-scale approach for the optimum design of sandwich plates with honeycomb core. Part I: homogenisation of core properties
http://hdl.handle.net/10985/8498
A multi-scale approach for the optimum design of sandwich plates with honeycomb core. Part I: homogenisation of core properties
CATAPANO, Anita; MONTEMURRO, Marco
This work deals with the problem of the optimum design of a sandwich panel. The design process is based on a general two-level optimisation strategy involving different scales: the meso-scale for both the unit cell of the core and the constitutive layer of the laminated skins and the macro-scale for the whole panel. Concerning the meso-scale of the honeycomb core, an appropriate model of the unit cell able to properly provide its effective elastic properties (to be used at the macro-scale) must be conceived. To this purpose, in this first paper, we present the numerical homogenisation technique as well as the related finite element model of the unit cell which makes use of solid elements instead of the usual shell ones. A numerical study to determine the effective properties of the honeycomb along with a comparison with existing models and a sensitive analysis in terms of the geometric parameters of the unit cell have been conducted. Numerical results show that shell-based models are no longer adapted to evaluate the core properties, mostly in the context of an optimisation procedure where the parameters of the unit cell can get values that go beyond the limits imposed by a 2D model.
Wed, 01 Jan 2014 00:00:00 GMThttp://hdl.handle.net/10985/84982014-01-01T00:00:00ZCATAPANO, AnitaMONTEMURRO, MarcoThis work deals with the problem of the optimum design of a sandwich panel. The design process is based on a general two-level optimisation strategy involving different scales: the meso-scale for both the unit cell of the core and the constitutive layer of the laminated skins and the macro-scale for the whole panel. Concerning the meso-scale of the honeycomb core, an appropriate model of the unit cell able to properly provide its effective elastic properties (to be used at the macro-scale) must be conceived. To this purpose, in this first paper, we present the numerical homogenisation technique as well as the related finite element model of the unit cell which makes use of solid elements instead of the usual shell ones. A numerical study to determine the effective properties of the honeycomb along with a comparison with existing models and a sensitive analysis in terms of the geometric parameters of the unit cell have been conducted. Numerical results show that shell-based models are no longer adapted to evaluate the core properties, mostly in the context of an optimisation procedure where the parameters of the unit cell can get values that go beyond the limits imposed by a 2D model.Simultaneous shape and material optimization of sandwich panels with honeycomb core for additive manufacturing
http://hdl.handle.net/10985/9922
Simultaneous shape and material optimization of sandwich panels with honeycomb core for additive manufacturing
MONTEMURRO, Marco; CATAPANO, Anita; DOROSZEWSKI, Dominique
This works deals with the problem of the optimum design of a sandwich plate composed of CFRP faces and Al honeycomb core. The proposed design strategy is a multi-scale numerical optimization procedure that does not make use of any simplifying assumption to find a global optimum configuration of the system. The goal of such a procedure consists in simultaneously optimizing the shape of the unit cell of the honeycomb core (meso-scale) and the geometrical as well as the material parameters of the CFRP laminated skins (meso and macro scales). To prove its effectiveness, the multi-scale optimization strategy is applied to the problem of the least-weight design of a sandwich panel subject to constraints of different nature: on the positive-definiteness of the stiffness tensor of the core, on the admissible material properties of the laminated faces, on the local buckling load of the unit cell of the core, on the global buckling load of the panel and geometrical as well as manufacturability constraints linked to the fabrication process of the honeycomb core.
Thu, 01 Jan 2015 00:00:00 GMThttp://hdl.handle.net/10985/99222015-01-01T00:00:00ZMONTEMURRO, MarcoCATAPANO, AnitaDOROSZEWSKI, DominiqueThis works deals with the problem of the optimum design of a sandwich plate composed of CFRP faces and Al honeycomb core. The proposed design strategy is a multi-scale numerical optimization procedure that does not make use of any simplifying assumption to find a global optimum configuration of the system. The goal of such a procedure consists in simultaneously optimizing the shape of the unit cell of the honeycomb core (meso-scale) and the geometrical as well as the material parameters of the CFRP laminated skins (meso and macro scales). To prove its effectiveness, the multi-scale optimization strategy is applied to the problem of the least-weight design of a sandwich panel subject to constraints of different nature: on the positive-definiteness of the stiffness tensor of the core, on the admissible material properties of the laminated faces, on the local buckling load of the unit cell of the core, on the global buckling load of the panel and geometrical as well as manufacturability constraints linked to the fabrication process of the honeycomb core.A new design paradigm for the analysis and optimisation of composite structures
http://hdl.handle.net/10985/9923
A new design paradigm for the analysis and optimisation of composite structures
MONTEMURRO, Marco
A new design paradigm for the analysis and optimisation of composite structures
Thu, 01 Jan 2015 00:00:00 GMThttp://hdl.handle.net/10985/99232015-01-01T00:00:00ZMONTEMURRO, MarcoA new design paradigm for the analysis and optimisation of composite structuresA multi-scale approach for the optimum design of sandwich plates with honeycomb core. Part II: the optimisation strategy
http://hdl.handle.net/10985/8493
A multi-scale approach for the optimum design of sandwich plates with honeycomb core. Part II: the optimisation strategy
CATAPANO, Anita; MONTEMURRO, Marco
This work deals with the problem of the optimum design of a sandwich panel. The design strategy that we propose is a numerical optimisation procedure that does not make any simplifying assumption to obtain a true global optimum configuration of the system. To face the design of the sandwich structure at both meso and macro scales, we use a two-level optimisation strategy: at the first level we determine the optimal geometry of the unit cell of the core together with the material and geometric parameters of the laminated skins, while at the second level we determine the optimal skins lay-up giving the geometrical and material parameters issued from the first level. The two-level strategy relies both on the use of the polar formalism for the description of the anisotropic behaviour of the laminates and on the use of a genetic algorithm as optimisation tool to perform the solution search. To prove its effectiveness, we apply our strategy to the least-weight design of a sandwich plate, satisfying several constraints: on the first buckling load, on the positive-definiteness of the stiffness tensor of the core, on the ratio between skins and core thickness and on the admissible moduli for the laminated skins.
Wed, 01 Jan 2014 00:00:00 GMThttp://hdl.handle.net/10985/84932014-01-01T00:00:00ZCATAPANO, AnitaMONTEMURRO, MarcoThis work deals with the problem of the optimum design of a sandwich panel. The design strategy that we propose is a numerical optimisation procedure that does not make any simplifying assumption to obtain a true global optimum configuration of the system. To face the design of the sandwich structure at both meso and macro scales, we use a two-level optimisation strategy: at the first level we determine the optimal geometry of the unit cell of the core together with the material and geometric parameters of the laminated skins, while at the second level we determine the optimal skins lay-up giving the geometrical and material parameters issued from the first level. The two-level strategy relies both on the use of the polar formalism for the description of the anisotropic behaviour of the laminates and on the use of a genetic algorithm as optimisation tool to perform the solution search. To prove its effectiveness, we apply our strategy to the least-weight design of a sandwich plate, satisfying several constraints: on the first buckling load, on the positive-definiteness of the stiffness tensor of the core, on the ratio between skins and core thickness and on the admissible moduli for the laminated skins.A new multi-scale design methodology for the optimisation of variable stiffness composites
http://hdl.handle.net/10985/12936
A new multi-scale design methodology for the optimisation of variable stiffness composites
MONTEMURRO, Marco; CATAPANO, Anita
In this work a multi-scale two-level (MS2L) optimisation strategy for optimising VAT composites is presented. In the framework of the MS2L methodology, the design problem is split and solved into two steps. At the first step the goal is to determine the optimum distribution of the laminate stiffness properties over the structure (macroscopic scale), while the second step aims at retrieving the optimum fibres path in each layer meeting all the requirements provided by the problem at hand (mesoscopic scale). The MS2L strategy has been improved in order to integrate all types of requirements (mechanical, manufacturability, geometric, etc.) within the first-level problem. The proposed approach relies on: (a) the polar formalism for describing the behaviour of the VAT laminate, (b) the iso-geometric surfaces for describing the spatial variation of both the laminate stiffness properties (macro-scale) and the layers fibres-path (meso-scale) and (c) an hybrid optimisation tool (genetic and gradient-based algorithms) to perform the solution search. The effectiveness of the MS2L strategy is proven through a numerical example on the maximisation of the first buckling factor of a VAT plate subject to both mechanical and manufacturability constraints.
Sun, 01 Jan 2017 00:00:00 GMThttp://hdl.handle.net/10985/129362017-01-01T00:00:00ZMONTEMURRO, MarcoCATAPANO, AnitaIn this work a multi-scale two-level (MS2L) optimisation strategy for optimising VAT composites is presented. In the framework of the MS2L methodology, the design problem is split and solved into two steps. At the first step the goal is to determine the optimum distribution of the laminate stiffness properties over the structure (macroscopic scale), while the second step aims at retrieving the optimum fibres path in each layer meeting all the requirements provided by the problem at hand (mesoscopic scale). The MS2L strategy has been improved in order to integrate all types of requirements (mechanical, manufacturability, geometric, etc.) within the first-level problem. The proposed approach relies on: (a) the polar formalism for describing the behaviour of the VAT laminate, (b) the iso-geometric surfaces for describing the spatial variation of both the laminate stiffness properties (macro-scale) and the layers fibres-path (meso-scale) and (c) an hybrid optimisation tool (genetic and gradient-based algorithms) to perform the solution search. The effectiveness of the MS2L strategy is proven through a numerical example on the maximisation of the first buckling factor of a VAT plate subject to both mechanical and manufacturability constraints.Architecture and materials selection in multi-materials design
http://hdl.handle.net/10985/8514
Architecture and materials selection in multi-materials design
BARACCHINI, Paul; GUILLEBAUD, Claire; KROMM, François-Xavier; CATAPANO, Anita; MONTEMURRO, Marco; WARGNIER, Hervé
The design process involving both the architecture and the materials represents an hard task mainly due to the high number of potential configurations, thus requiring firstly the development of new and more rigorous approaches but also the development of new tools. To this purpose, we present in this work a new strategy for the design of architectured materials. Such a strategy relies on one hand on the construction of some databases for the selection of both geometrical patterns and materials, and on the other hand on the use of well-known analytical models to describe the physical behaviour of the multi-material. In order to prove its effectiveness, we apply our strategy to the problem of the least-weight design of a multilayer plate that has to meet thermal, electrical and mechanical requirements. Moreover, we use a genetic algorithm, as a numerical tool, to perform the solution search for our problem. Numerical results show that we can obtain optimum configurations characterised by a weight saving up to 59% keeping the same (or even superior) thermal, electrical and stiffness properties than those of a monolithic reference plate.
Wed, 01 Jan 2014 00:00:00 GMThttp://hdl.handle.net/10985/85142014-01-01T00:00:00ZBARACCHINI, PaulGUILLEBAUD, ClaireKROMM, François-XavierCATAPANO, AnitaMONTEMURRO, MarcoWARGNIER, HervéThe design process involving both the architecture and the materials represents an hard task mainly due to the high number of potential configurations, thus requiring firstly the development of new and more rigorous approaches but also the development of new tools. To this purpose, we present in this work a new strategy for the design of architectured materials. Such a strategy relies on one hand on the construction of some databases for the selection of both geometrical patterns and materials, and on the other hand on the use of well-known analytical models to describe the physical behaviour of the multi-material. In order to prove its effectiveness, we apply our strategy to the problem of the least-weight design of a multilayer plate that has to meet thermal, electrical and mechanical requirements. Moreover, we use a genetic algorithm, as a numerical tool, to perform the solution search for our problem. Numerical results show that we can obtain optimum configurations characterised by a weight saving up to 59% keeping the same (or even superior) thermal, electrical and stiffness properties than those of a monolithic reference plate.Corrigendum to "An extension of the polar method to the First-order Shear Deformation Theory of laminates" [Compos. Struct. 127 (2015) 328-339]
http://hdl.handle.net/10985/9920
Corrigendum to "An extension of the polar method to the First-order Shear Deformation Theory of laminates" [Compos. Struct. 127 (2015) 328-339]
MONTEMURRO, Marco
Corrigendum to "An extension of the polar method to the First-order Shear Deformation Theory of laminates" [Compos. Struct. 127 (2015) 328-339]
This is a Corrigendum to a previous publication entitled: "An extension of the polar method to the First-order Shear Deformation Theory of laminates"
Thu, 01 Jan 2015 00:00:00 GMThttp://hdl.handle.net/10985/99202015-01-01T00:00:00ZMONTEMURRO, MarcoCorrigendum to "An extension of the polar method to the First-order Shear Deformation Theory of laminates" [Compos. Struct. 127 (2015) 328-339]