SAM
https://sam.ensam.eu:443
The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.Sun, 16 Jun 2024 22:06:14 GMT2024-06-16T22:06:14ZA general multi-scale two-level optimisation strategy for designing composite stiffened panels
http://hdl.handle.net/10985/17338
A general multi-scale two-level optimisation strategy for designing composite stiffened panels
PAGANI, Alfonso; FIORDILINO, Giacinto Alberto; PAILHES, Jerome; CARRERA, Erasmo; MONTEMURRO, Marco
This work deals with the problem of the least-weight design of a composite stiffened panel subject to constraints of different nature (mechanical, geometrical and manufacturability requirements). To face this problem, a multi-scale two-level (MS2L) design methodology is proposed. This approach aims at optimising simultaneously both geometrical and mechanical parameters for skin and stiffeners at each characteristic scale (mesoscopic and macroscopic ones). In this background, at the first level (macroscopic scale) the goal is to find the optimum value of geometric and mechanical design variables of the panel minimising its mass and meeting the set of imposed constraints. The second-level problem focuses on the laminate mesoscopic scale and aims at finding at least one stacking sequence (for each laminate composing the panel) meeting the geometrical and material parameters provided by the first-level problem. The MS2L optimisation approach is based on the polar formalism to describe the macroscopic behaviour of the composites and on a special genetic algorithm to perform optimisation calculations. The quality of the optimum configurations is investigated, a posteriori, through a refined finite element model of the stiffened panel making use of elements with different kinematics and accuracy in the framework of the Carrera's Unified Formulation (CUF).
Mon, 01 Jan 2018 00:00:00 GMThttp://hdl.handle.net/10985/173382018-01-01T00:00:00ZPAGANI, AlfonsoFIORDILINO, Giacinto AlbertoPAILHES, JeromeCARRERA, ErasmoMONTEMURRO, MarcoThis work deals with the problem of the least-weight design of a composite stiffened panel subject to constraints of different nature (mechanical, geometrical and manufacturability requirements). To face this problem, a multi-scale two-level (MS2L) design methodology is proposed. This approach aims at optimising simultaneously both geometrical and mechanical parameters for skin and stiffeners at each characteristic scale (mesoscopic and macroscopic ones). In this background, at the first level (macroscopic scale) the goal is to find the optimum value of geometric and mechanical design variables of the panel minimising its mass and meeting the set of imposed constraints. The second-level problem focuses on the laminate mesoscopic scale and aims at finding at least one stacking sequence (for each laminate composing the panel) meeting the geometrical and material parameters provided by the first-level problem. The MS2L optimisation approach is based on the polar formalism to describe the macroscopic behaviour of the composites and on a special genetic algorithm to perform optimisation calculations. The quality of the optimum configurations is investigated, a posteriori, through a refined finite element model of the stiffened panel making use of elements with different kinematics and accuracy in the framework of the Carrera's Unified Formulation (CUF).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
PAGANI, Alfonso; FIORDILINO, Giacinto Alberto; PAILHES, Jerome; CARRERA, Erasmo; MONTEMURRO, Marco
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/10985/129382017-01-01T00:00:00ZPAGANI, AlfonsoFIORDILINO, Giacinto AlbertoPAILHES, JeromeCARRERA, ErasmoMONTEMURRO, Marcothis 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-level optimisation of composite structures through a global-local modelling approach based on high-order theories
http://hdl.handle.net/10985/25065
Multi-level optimisation of composite structures through a global-local modelling approach based on high-order theories
MONTEMURRO, Marco; FIORDILINO, Giacinto Alberto; CARRERA, Erasmo
This paper presents an original multi-level optimisation method for the design of composite structures integrating a globalâ€“local approach based on higher-order theories to assess the responses of the structure at each scale. The method offers a good balance between accuracy and computational costs. Unlike multi-level strategies available in the literature, in the proposed approach there is a strong interaction between the steps of the optimisation process. The proposed method is articulated in two nested optimisation loops (outer and inner). The outer loop focuses on the macroscopic scale where the polar formalism is used to describe the laminate behaviour. The resolution of the outer loop is performed through a special metaheuristic algorithm. However, since requirements on local structural responses are evaluated on the most critical region of the structure (modelled through a higher-order theory) at the ply-level, for each solution of the outer loop, a nested genetic optimisation (inner loop) is performed to find the stack matching the values of the geometric variables and of the polar parameters corresponding to the current solution of the outer loop. During the inner loop, the optimised stacking sequences are searched in the domain of general quasi-trivial solutions, without introducing simplifying hypotheses.
The new methodology is applied to the least-weight design of a simplified wing-box structure by considering requirements of both mechanical nature (first buckling load, first-ply failure, and delamination) and technological nature (blending between adjacent laminates).
Sun, 01 Jan 2023 00:00:00 GMThttp://hdl.handle.net/10985/250652023-01-01T00:00:00ZMONTEMURRO, MarcoFIORDILINO, Giacinto AlbertoCARRERA, ErasmoThis paper presents an original multi-level optimisation method for the design of composite structures integrating a globalâ€“local approach based on higher-order theories to assess the responses of the structure at each scale. The method offers a good balance between accuracy and computational costs. Unlike multi-level strategies available in the literature, in the proposed approach there is a strong interaction between the steps of the optimisation process. The proposed method is articulated in two nested optimisation loops (outer and inner). The outer loop focuses on the macroscopic scale where the polar formalism is used to describe the laminate behaviour. The resolution of the outer loop is performed through a special metaheuristic algorithm. However, since requirements on local structural responses are evaluated on the most critical region of the structure (modelled through a higher-order theory) at the ply-level, for each solution of the outer loop, a nested genetic optimisation (inner loop) is performed to find the stack matching the values of the geometric variables and of the polar parameters corresponding to the current solution of the outer loop. During the inner loop, the optimised stacking sequences are searched in the domain of general quasi-trivial solutions, without introducing simplifying hypotheses.
The new methodology is applied to the least-weight design of a simplified wing-box structure by considering requirements of both mechanical nature (first buckling load, first-ply failure, and delamination) and technological nature (blending between adjacent laminates).