A general global-local modelling framework for the deterministic optimisation of composite structures
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RESEARCH PAPER
A general global-local modelling framework for the deterministic optimisation of composite structures Marco Picchi Scardaoni1,2 · Marco Montemurro1 Received: 28 January 2020 / Revised: 18 March 2020 / Accepted: 27 March 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract This work deals with the multi-scale optimisation of composite structures by adopting a general global-local (GL) modelling strategy to assess the structure responses at different scales. The GL modelling approach is integrated into the multiscale two-level optimisation strategy (MS2LOS) for composite structures. The resulting design strategy is, thus, called GL-MS2LOS and aims at proposing a very general formulation of the design problem, without introducing simplifying hypotheses on the laminate stack and by considering, as design variables, the full set of geometric and mechanical parameters defining the behaviour of the composite structure at each pertinent scale. By employing a GL modelling approach, most of the limitations of well-established design strategies, based on analytical or semi-empirical models, are overcome. The GLMS2LOS makes use of the polar formalism to describe the anisotropy of the composite at the macroscopic scale (where it is modelled as an equivalent homogeneous anisotropic plate). In this work, deterministic algorithms are exploited during the solution search phase. The challenge, when dealing with such a design problem, is to develop a suitable formulation and dedicated operators, to link global and local models physical responses and their gradients. Closed-form expressions of structural responses gradients are rigorously derived by taking into account for the coupling effects when passing from global to local models. The effectiveness of the GL-MS2LOS is proven on a meaningful benchmark: the least-weight design of a cantilever wing subject to different design requirements. Constraints include maximum allowable displacements, maximum allowable strains, blending, manufacturability requirements and buckling factor. Keywords Composites · Anisotropy · Polar method · Deterministic optimisation · Buckling · Global/local modelling approach
1 Introduction Last decades have seen an increasing interest in the study and in the use of composite materials, especially for aeronautical structures. Composite materials allow for a greater freedom in the design process when compared to metal alloys. In fact, the material itself can be tailored according to the requirements of the problem at hand. Furthermore, high specific stiffness and specific strength make composite materials appealing for the aeronautical industry. Responsible Editor: Emilio Carlos Nelli Silva Marco Montemurro
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Despite these advantages, many difficulties arise since the initial design phases. Issues are mainly related to the mathematical description of anisotropy, as well as to the scale separat
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