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DTSTART;TZID=Europe/Paris:20261021T140000
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DTSTAMP:20261002T161023Z
CREATED:20261002T161022Z
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UID:15719-1792591200-1792594800@gem.ec-nantes.fr
SUMMARY:Séminaire Martin Ladecký
DESCRIPTION:Jacobi-Accelerated FFT Solver for Topology Optimization of MetamaterialsMartin Ladeckýmartin.ladecky@imtek.uni-freiburg.deThe exotic properties of mechanical metamaterials arise from the geometry of their microstructure. Topology optimization of microstructures [1] is nontrivial and computationally expensive\, as it requires repeatedly solving homogenization problems. Solvers based on the fast Fourier transform (FFT) are a standard tool for homogenization problems [2\,3]\, offering quasilinear O(N log N) complexity and excellent performance on regular grids. However\, their convergence deteriorates markedly when the material coefficients are smooth and highly contrasted [4]\, a regime frequently encountered in density-based topology optimization.In my talk\, I will present the Jacobi-accelerated FFT (J-FFT) solver [4]\, designed specifically for this setting. The method augments the classical discrete Green operator [5] with a diagonal Jacobi scaling that captures local material contrast while preserving the O(N log N) complexity per iteration. Although the strict grid-size independence of the standard Green preconditioner is relaxed\, the J-FFT solver yields substantially faster convergence for smooth\, high-contrast coefficient fields. In phase-field topology optimization of mechanical metamaterials\, where the density field becomes smooth and highly contrasted\, J-FFT consistently outperforms the standard FFT-based solver.References[1] O. Sigmund\, Materials with prescribed constitutive parameters: An inverse homogenization problem\, Int. J. Solids Struct. 31(17) (1994) 2313–2329.[2] H. Moulinec and P. Suquet\, A fast numerical method for computing the linear and nonlinear mechanical properties of composites\, C. R. Acad. Sci. Paris\, Série II 318(11) (1994) 1417–1423.[3] M. Schneider\, A review of nonlinear FFT-based computational homogenization methods\, Acta Mechanica 232 (2021) 2051–2100.[4] M. Ladecký\, I. Pultarová\, F. Bignonnet\, I. Jödicke\, J. Zeman\, and L. Pastewka\, Jacobi-accelerated FFT-based solver for smooth high-contrast data\, Comput. Methods Appl. Mech. Engrg. 461 (2026) 119269.[5] M. Ladecký\, R. J. Leute\, A. Falsafi\, I. Pultarová\, L. Pastewka\, T. Junge\, and J. Zeman\, An optimal preconditioned FFT-accelerated finite element solver for homogenization\, Appl. Math. Comput. 446 (2023) 127835.
URL:https://gem.ec-nantes.fr/event/seminaire-martin-ladecky/
LOCATION:salle séminaire du Bat 17 sur le site d’Heinlex à Saint-Nazaire\, Rue Pierre-Marie Juret\, Saint-Nazaire\, 44600\, France
ATTACH;FMTTYPE=image/jpeg:https://gem.ec-nantes.fr/wp-content/uploads/2026/10/Martin-Ladecky.jpg
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DTSTART;TZID=Europe/Paris:20261105T103000
DTEND;TZID=Europe/Paris:20261105T130000
DTSTAMP:20261014T143335Z
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UID:16142-1793874600-1793883600@gem.ec-nantes.fr
SUMMARY:Accueil des nouveaux arrivants au GeM
DESCRIPTION:Cette journée est consacrée de faire découvrir le GeM aux collègues et doctorants qui ont rejoint le GeM à partir de la rentrée 2026. Cette année\, elle aura lieu sur le campus de l'Ecole Centrale. Après une présentation du Laboratoire \, de son fonctionnement scientifique\, technique et administratif \, une visité des plateformes sur le site de l’École Centrale est proposée. RDV à l'Espace Accueil du GeM\, Bâtiment F à 9h30
URL:https://gem.ec-nantes.fr/event/accueil-des-nouveaux-arrivants-au-gem/
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DTSTART;TZID=Europe/Paris:20261126T093000
DTEND;TZID=Europe/Paris:20261126T183000
DTSTAMP:20261014T143335Z
CREATED:20261014T143335Z
LAST-MODIFIED:20261014T143335Z
UID:16143-1795685400-1795717800@gem.ec-nantes.fr
SUMMARY:Journée AFM "Place des Femmes en Mécanique"
DESCRIPTION:https://journeeafm2026.sciencesconf.org/?lang=f r La journée ouverte à tou·te·s pourra être suivie en visio à Nantes et à Saint Nazaire : – à Nantes sur le campus de la Lombarderie\, amphi pasteur – à Saint-Nazaire sur le campus Heinlex\, salle 8.102
URL:https://gem.ec-nantes.fr/event/journee-afm-place-des-femmes-en-mecanique/
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