Is the narrow 2 mm laser-cut bracket region a mesh artefact?
research/simdesign-gaugemesh
The narrow 2 mm laser-cut bracket region is a mesh effect: all 39 designs feasible at h = 2.5 mm fail the stress limit at h ≤ 1.5 mm (peak 1.09–1.27× higher, still rising at 0.75 mm); stylised, negative for the search mesh.
What it found
A negative result for the search mesh (stylised). All 39 gauge-2 bracket designs that were feasible on the 2.5 mm search mesh (19 under laser rules, 20 for the no-rules twin) are infeasible on finer meshes (1.5, 1.0, 0.75 mm): the peak von Mises stress is 1.09–1.27× higher at 0.75 mm and is still rising, at the point where the fillet meets the arm. Tip deflection is unchanged and the fillet facet count is not the cause. Earlier mass prices in the bracket chain are therefore conditional on the coarse mesh; no fine-mesh optimum was searched.
A figure from its own output
Paper, code and results
More in Simulation-first design
- Does a patch-averaged stress make the 2 mm laser-cut bracket region mesh-independent?A 3 mm patch-averaged stress converges with the mesh (≤2.2% change from h = 1.0 to 0.75 mm) where the centroid peak does not, and all 39 gauge-2 designs stay feasible; stylised, preliminary.
- Does the peak stress at the fillet tangent point of the L-bracket converge under graded mesh refinement?Does the L-bracket's peak stress at the fillet tangent point converge under graded mesh refinement? Yes for four designs: it flattens at 1.09–1.14× its 1.5 mm value (0.0–1.1% change over the last 4× refinement down to 0.025 mm), so the 2 mm region's mesh dependence is a resolution effect; the 16/15/2 design is marginally over 100 MPa when converged; stylised 2D, no reference solution.
- Is the least-mass laser-cut bracket the same on coarse and fine meshes under a patch-averaged stress rule?Under a 3 mm patch-averaged stress rule the least-mass laser-cut bracket is the same on a 2.5 mm and a 1.0 mm mesh (gauge 2: 32.31 vs 32.33 g), while the centroid-peak rule leaves no feasible gauge-2 design on the fine mesh; the patch value hardly sees the fillet radius; stylised, preliminary.
- Do cheap beam and 2D models rank candidate cantilever designs like 3D finite elements?Do cheap beam and 2D models rank cantilever designs like 3D finite elements? Yes on 3 seeds of 80 designs: Kendall τ 0.987–0.996 and the 3D-best design always ranked first, even though single-design merit is off by up to 14%; stubby sections agree least; stylised, one load case.
- Can a parametric L-bracket be sized by finite elements for minimum mass and come out printable?Parametric L-bracket sized by 2D finite elements (scikit-fem) for minimum mass under a stress limit: differential evolution 19.6 g vs random 25.6 g vs grid 31.4 g at equal budget, exported as STL with a printability check. Assumed material inputs. Stylised.
- Does greedy substitution search still work when the printer-redesign list grows past seven items?Does greedy substitution search still work past seven items (synthetic instances, assumed generator): 96–100% of the exact optimum on average but optimal in only 33–95 of 100 instances; 64 random evaluations fall to about 89% at 24 items.
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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.