Browsing by Author "Crescenti, Fabio"

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    Generating minimal Pareto sets in multi-objective topology optimisation: an application to the wing box structural layout
    (Springer, 2020-10-26) Crescenti, Fabio; Kipouros, Timoleon; Munk, David J.; Savill, Mark A.
    Multi-objective topology optimisation problems are often tackled by compromising the cost functions according to the designer’s knowledge. Such an approach however has clear limitations and usually requires information which especially at the preliminary design stage could be unavailable. This paper proposes an alternative multi-objective approach for the generation of minimal Pareto sets in combination with density-based topology optimisation. Optimised solutions are generated integrating a recently revised method for a posteriori articulation of preferences with the Method of Moving Asymptotes. The methodology is first tested on an academic two-dimensional structure and eventually employed to optimise a full-scale aerospace structure with the support of the commercial software Altair OptiStructⓇ. For the academic benchmark, the optimised layouts with respect to static and dynamic objectives are visualised on the Pareto frontier and reported with the corresponding density distribution. Results show a progressive and consistent transition between the two extreme single-objective layouts and confirm that the minimum number of evaluations was required to fill the smart Pareto front. The multi-objective strategy is then coupled with Altair OptiStruct and used to optimise a full-scale wing box, with the clear purpose to fill a gap in multi-objective topology optimisation applied to the wing primary structure. The proposed methodology proved that it can generate efficiently non-dominated optimised configurations, at a computational cost that is mainly driven by the model complexity. This strategy is particularly indicated for the preliminary design phase, as it releases the designer from the burden to assign preferences. Furthermore, the ease of integration into a commercial design tool makes it available for industrial applications.
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    Loading and planform shape influence on the wing structural layout through topology optimization
    (AIAA, 2018-07-31) Crescenti, Fabio; Kipouros, Timoleon; Savill, Mark
    Topology optimization is a technique used to identify the optimal layout of a structure for a given objective and assigned boundary conditions. The progress it has experienced over the last three decades made it ready for industrial applications. In this paper topology optimization is employed to investigate the influence of sweep angle, aspect ratio and loading condition on the wing internal structure. The planform of the Common Research Model wing is used as a baseline. The geometry is modified parametrically to alter sweep angle and aspect ratio. Regarding the baseline planform, the optimization is performed considering the aerodynamic loading induced by the pull-up manoeuvre. Results are provided for AR=7 and AR=1, as well as sweep angle of 20 and 30 degrees. The results of topology optimization for all cases are compared. Common patterns are identified and exported to provide guidelines for the preliminary design of the wing primary structure.
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    pseudocode.pdf
    (Cranfield University, 2020-10-08 15:30) Crescenti, Fabio
    This pseudocode contains information useful to reproduce the results presented in the journal paper: Generating minimal Pareto sets in multi-objective topologyoptimisation: an application to the wing box structural layout.