Multi-objective topology optimisation for acoustic porous materials using gradient-based, gradient-free, and hybrid strategies

• Published in: The Journal of the Acoustical Society of America Vol. 153; no. 5; pp. 2945 - 2955
• Main Authors: Ramamoorthy, Vivek T., Özcan, Ender, Parkes, Andrew J., Jaouen, Luc, Bécot, François-Xavier
• Format: Journal Article
• Language: English
• Published: United States 01.05.2023
• ISSN: 0001-4966; 1520-8524; 1520-8524
• DOI: 10.1121/10.0019455

When designing passive sound-attenuation structures, one of the challenging problems that arise is optimally distributing acoustic porous materials within a design region so as to maximise sound absorption while minimising material usage. To identify efficient optimisation strategies for this multi-objective problem, several gradient, non-gradient, and hybrid topology optimisation strategies are compared. For gradient approaches, the solid-isotropic-material-with-penalisation method and a gradient-based constructive heuristic are considered. For gradient-free approaches, hill climbing with a weighted-sum scalarisation and a non-dominated sorting genetic algorithm-II are considered. Optimisation trials are conducted on seven benchmark problems involving rectangular design domains in impedance tubes subject to normal-incidence sound loads. The results indicate that while gradient methods can provide quick convergence with high-quality solutions, often gradient-free strategies are able to find improvements in specific regions of the Pareto front. Two hybrid approaches are proposed, combining a gradient method for initiation and a non-gradient method for local improvements. An effective Pareto-slope-based weighted-sum hill climbing is introduced for local improvement. Results reveal that for a given computational budget, the hybrid methods can consistently outperform the parent gradient or non-gradient method.