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http://hdl.handle.net/10985/8514
Architecture and materials selection in multi-materials design
BARACCHINI, Paul; GUILLEBAUD, Claire; KROMM, François-Xavier; WARGNIER, Hervé; MONTEMURRO, Marco; CATAPANO, Anita
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-XavierWARGNIER, HervéMONTEMURRO, MarcoCATAPANO, AnitaThe 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.A new multi-scale optimisation strategy for designing variable angle tow composites by integrating manufacturing constraints
http://hdl.handle.net/10985/12874
A new multi-scale optimisation strategy for designing variable angle tow composites by integrating manufacturing constraints
MONTEMURRO, Marco
In this work a multi-scale two-level (MS2L) optimisation strategy for optimising variable angle tow (VAT) composites is presented. In the framework of the MS2L methodology [1], [2], [3] 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 design strategy is characterised on the one hand by the refusal of simplifying hypotheses and classical rules usually employed in the framework of the design process of laminates, and on the other hand by a proper and complete mathematical formalisation of the optimum design problem at each characteristic scale (meso-macro). The MS2L strategy relies on the use of the polar formalism (extended to the case of higher-order theories [4], [5]) for the description of the anisotropic behaviour of the composite. The real advantage in using the Verchery's polar method is in the fact that the elastic response of the structure at the macro-scale is described in terms of tensor invariants, the so-called polar parameters, having a precise physical meaning (which is linked to the elastic symmetries of the material) [4]. On the other hand the MS2L strategy relies on the use of a particular genetic algorithm (GA) able to deal with a special class of huge-size optimisation problems (from hundreds to thousands of design variables) defined over a domain of variable dimension, i.e. optimisation problems involving a variable number of design variables [6]. The MS2L strategy has been improved in order to integrate all types of requirements (mechanical, manufacturability, geometric, etc.) within the first-level problem [3]. Several modifications have been introduced in the theoretical and numerical framework of the MS2L design procedure at both first and second levels [2], [3]. At the first level (laminate macroscopic scale) of the procedure, where the VAT laminate is modelled as an equivalent homogeneous anisotropic plate whose mechanical behaviour is described in terms of polar parameters (which vary locally over the structure), the major modifications focus on: 1) the utilisation of higher-order theories (First-order Shear Deformation Theory (FSDT) framework [4], [5] for taking into account the influence of the transverse shear stiffness on the overall mechanical response of VAT composites; 2) the utilisation of B-spline surfaces for obtaining a continuous point-wise variation of the laminate polar parameters; 3) a proper mathematical formalisation of the manufacturability constraints linked to the AFP process in the framework of the B-spline representation and in terms of laminate polar parameters. Regarding the second-level problem (laminate mesoscopic scale, i.e. the ply level) the main modifications is the utilisation of B-spline surfaces for obtaining a continuous point-wise variation of the fibres-path within each ply. Accordingly, the second-level problem (the lay-up design) can now be formulated as an unconstrained minimisation problem as all the requirements (geometrical, technological, mechanical, etc.) are satisfied since the first step of the MS2L strategy. All of these modifications imply several advantages for the resolution of the related optimisation problems (both at first and second level of the strategy) as detailed in [3]. 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/10985/128742017-01-01T00:00:00ZMONTEMURRO, MarcoIn this work a multi-scale two-level (MS2L) optimisation strategy for optimising variable angle tow (VAT) composites is presented. In the framework of the MS2L methodology [1], [2], [3] 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 design strategy is characterised on the one hand by the refusal of simplifying hypotheses and classical rules usually employed in the framework of the design process of laminates, and on the other hand by a proper and complete mathematical formalisation of the optimum design problem at each characteristic scale (meso-macro). The MS2L strategy relies on the use of the polar formalism (extended to the case of higher-order theories [4], [5]) for the description of the anisotropic behaviour of the composite. The real advantage in using the Verchery's polar method is in the fact that the elastic response of the structure at the macro-scale is described in terms of tensor invariants, the so-called polar parameters, having a precise physical meaning (which is linked to the elastic symmetries of the material) [4]. On the other hand the MS2L strategy relies on the use of a particular genetic algorithm (GA) able to deal with a special class of huge-size optimisation problems (from hundreds to thousands of design variables) defined over a domain of variable dimension, i.e. optimisation problems involving a variable number of design variables [6]. The MS2L strategy has been improved in order to integrate all types of requirements (mechanical, manufacturability, geometric, etc.) within the first-level problem [3]. Several modifications have been introduced in the theoretical and numerical framework of the MS2L design procedure at both first and second levels [2], [3]. At the first level (laminate macroscopic scale) of the procedure, where the VAT laminate is modelled as an equivalent homogeneous anisotropic plate whose mechanical behaviour is described in terms of polar parameters (which vary locally over the structure), the major modifications focus on: 1) the utilisation of higher-order theories (First-order Shear Deformation Theory (FSDT) framework [4], [5] for taking into account the influence of the transverse shear stiffness on the overall mechanical response of VAT composites; 2) the utilisation of B-spline surfaces for obtaining a continuous point-wise variation of the laminate polar parameters; 3) a proper mathematical formalisation of the manufacturability constraints linked to the AFP process in the framework of the B-spline representation and in terms of laminate polar parameters. Regarding the second-level problem (laminate mesoscopic scale, i.e. the ply level) the main modifications is the utilisation of B-spline surfaces for obtaining a continuous point-wise variation of the fibres-path within each ply. Accordingly, the second-level problem (the lay-up design) can now be formulated as an unconstrained minimisation problem as all the requirements (geometrical, technological, mechanical, etc.) are satisfied since the first step of the MS2L strategy. All of these modifications imply several advantages for the resolution of the related optimisation problems (both at first and second level of the strategy) as detailed in [3]. 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.On the effective integration of manufacturability constraints within the multi-scale methodology for designing variable angle-tow laminates
http://hdl.handle.net/10985/11438
On the effective integration of manufacturability constraints within the multi-scale methodology for designing variable angle-tow laminates
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/10985/114382017-01-01T00:00:00ZMONTEMURRO, 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.A 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.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
CAPPELLI, Lorenzo; GUILLAUMAT, Laurent; MONTEMURRO, Marco; DAU, Frédéric
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/10985/125402017-01-01T00:00:00ZCAPPELLI, LorenzoGUILLAUMAT, LaurentMONTEMURRO, MarcoDAU, FrédéricOne 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.Multi-scale identification of elastic properties for anisotropic media through a global hybrid evolutionary-based inverse approach
http://hdl.handle.net/10985/12937
Multi-scale identification of elastic properties for anisotropic media through a global hybrid evolutionary-based inverse approach
CAPPELLI, Lorenzo; GUILLAUMAT, Laurent; MONTEMURRO, Marco; DAU, Frédéric
One of the main issues of composite materials is related to the difficulty of characterising the full set of material properties at both mesoscopic and microscopic scales. Indeed, classical mechanical tests (traction/compression, 3 or 4 points bending tests, etc.) are not able to provide the full set of 3D material properties of composites. Furthermore, these tests can provide only the in-plane elastic properties of the constitutive lamina (i.e at. the laminate mesoscopic scale). Therefore, in order to go beyond the main restrictions imposed by standard destructive tests, this work deals with the problem of characterising the material properties of a composite plate made of unidirectional fibre-reinforced laminae (at each characteristic scale), through a single non-destructive modal test performed at the macroscale, i.e. that of the specimen (the laminate). To face such a problem a general multi-scale identification strategy (MSIS) is proposed. The MSIS aims at identifying the constitutive properties at both micro and meso scales by exploiting the information restrained in the macroscopic dynamical response of the laminate (e.g. in terms of its eigenfrequencies). The MSIS relies on the one hand on the strain energy homogenisation technique of periodic media (for determining the effective elastic properties of the lamina as a function of the geometrical and material properties of the microscopic constitutive phases) and on the other hand on a special hybrid algorithm (genetic algorithm + gradient-based algorithm) in order to perform the solution search for the considered problem. The identification problem is stated as a constrained inverse problem (a least-square constrained problem), where the objective function depends upon both the measured and evaluated (from finite element analysis) natural frequencies of the laminated plate. In this background, the optimisation variables are both geometrical and material properties of the constitutive phases composing the representative volume element (RVE) of the composite. The effectiveness of the proposed approach will be proven through a campaign of experimental/numerical tests conducted on standard laminates made of unidirectional plies.
Sun, 01 Jan 2017 00:00:00 GMThttp://hdl.handle.net/10985/129372017-01-01T00:00:00ZCAPPELLI, LorenzoGUILLAUMAT, LaurentMONTEMURRO, MarcoDAU, FrédéricOne of the main issues of composite materials is related to the difficulty of characterising the full set of material properties at both mesoscopic and microscopic scales. Indeed, classical mechanical tests (traction/compression, 3 or 4 points bending tests, etc.) are not able to provide the full set of 3D material properties of composites. Furthermore, these tests can provide only the in-plane elastic properties of the constitutive lamina (i.e at. the laminate mesoscopic scale). Therefore, in order to go beyond the main restrictions imposed by standard destructive tests, this work deals with the problem of characterising the material properties of a composite plate made of unidirectional fibre-reinforced laminae (at each characteristic scale), through a single non-destructive modal test performed at the macroscale, i.e. that of the specimen (the laminate). To face such a problem a general multi-scale identification strategy (MSIS) is proposed. The MSIS aims at identifying the constitutive properties at both micro and meso scales by exploiting the information restrained in the macroscopic dynamical response of the laminate (e.g. in terms of its eigenfrequencies). The MSIS relies on the one hand on the strain energy homogenisation technique of periodic media (for determining the effective elastic properties of the lamina as a function of the geometrical and material properties of the microscopic constitutive phases) and on the other hand on a special hybrid algorithm (genetic algorithm + gradient-based algorithm) in order to perform the solution search for the considered problem. The identification problem is stated as a constrained inverse problem (a least-square constrained problem), where the objective function depends upon both the measured and evaluated (from finite element analysis) natural frequencies of the laminated plate. In this background, the optimisation variables are both geometrical and material properties of the constitutive phases composing the representative volume element (RVE) of the composite. The effectiveness of the proposed approach will be proven through a campaign of experimental/numerical tests conducted on standard laminates made of unidirectional plies.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]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.A 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
MONTEMURRO, Marco; CATAPANO, Anita
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/10985/84932014-01-01T00:00:00ZMONTEMURRO, MarcoCATAPANO, AnitaThis 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.Optimal design of sandwich plates with honeycomb core
http://hdl.handle.net/10985/8504
Optimal design of sandwich plates with honeycomb core
MONTEMURRO, Marco; CATAPANO, Anita
This work deals with the problem of the optimum design of a sandwich structure composed of two laminated skins and a honeycomb core. The goal is to propose a numerical optimisation procedure that does not make any simplifying hypothesis in order to obtain a true global optimal solution for the considered problem. In order 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 optimum geometry of the unit cell 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. We will illustrate the application of our strategy to the least-weight design of a sandwich plate submitted to 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/10985/85042014-01-01T00:00:00ZMONTEMURRO, MarcoCATAPANO, AnitaThis work deals with the problem of the optimum design of a sandwich structure composed of two laminated skins and a honeycomb core. The goal is to propose a numerical optimisation procedure that does not make any simplifying hypothesis in order to obtain a true global optimal solution for the considered problem. In order 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 optimum geometry of the unit cell 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. We will illustrate the application of our strategy to the least-weight design of a sandwich plate submitted to 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.