Is the start-dependence of fixed-penalty SIMP topology optimisation just slow convergence?
research/simdesign-startsconverge
Is the start-dependence of fixed-penalty SIMP just slow convergence? Over 1200 iterations the median of 20 random starts reaches the uniform-start design (0.0% of elements differ, from 3.9% at 150), but the compliance spread only falls 1.43% → 0.85% (stylised, 2D, one mesh).
What it found
Follow-up to simdesign-starts. Half-MBB 60×20, p = 3, one uniform and 20 random starting fields (noise ±0.3), each run 1200 OC iterations and snapshotted at 150, 300, 600 and 1200. The median random start ends at the uniform-start design (0.0% of elements differ at 1200, 3.9% at 150) and the pair disagreement falls from 15.4% to 0.5%, but the compliance spread only falls from 1.43% to 0.85% and holes still range 2–5, so a minority of starts stay in a different, slightly worse local optimum. Stylised: 2D, one mesh, one noise level, stuck starts not counted.
A figure from its own output
Paper, code and results
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Produced with AI assistance (Claude). Results are from the code in this repository and are simulated or stylised unless the abstract says otherwise; nothing here implies affiliation with or endorsement by any lab, researcher or company cited. MIT licensed.