When does the buckling guard of the laser-cut bracket start to bind as load and arm length change?
research/simdesign-loadbind
Sweeping tip load (50–400 N) and arm length (60–120 mm) of the laser-cut bracket: the buckling-factor ≥ 3 guard binds only at 120 mm arms (unguarded optimum has factor 1.9; 69 g vs 59 g), while the old w/b ≤ 8 rule costs 14–25% in mass in five of six cases (stylised, two seeds).
What it found
A stylised, preliminary sweep (closed-form buckling check, assumed rules, material and loads; two seeds). Over tip loads of 50–400 N and arms of 60–120 mm, a lateral-torsional factor ≥ 3 guard binds in only one of six cases: 120 mm arms, where the unguarded optimum has a factor of 1.9 and the guard costs 16% in mass (69 g vs 59 g). The old w/b ≤ 8 rule was 14–25% heavier than the buckling guard in five of six cases. Gauge steps make mass non-smooth in load; the result moves with the assumed factor.
Paper, code and results
More in Simulation-first design
- How sharp is the feasible edge of the 2 mm laser-cut bracket web at 0.1 mm resolution, and is it mesh noise?A 0.1 mm scan of the feasible edge of the gauge-2 bracket web (nine mesh/radius cases): peak stress is not monotone in w, with residual jitter of 0.9–2.4 MPa about a quadratic trend, the same size as the 0.1–1.7 MPa gap to the 100 MPa limit just below each edge, so the edge is a band of about 0.5 mm and the earlier refinement shift is not separated from mesh noise; stylised, preliminary.
- Do wider webs of the 2 mm laser-cut bracket stay feasible on fine meshes when the slenderness rule is relaxed?With the assumed slenderness limit raised from 8 to 12.5, gauge-2 bracket webs of 16–17 mm and wider are feasible at h = 1.5, 1.0 and 0.75 mm; refinement from 1.5 to 1.0 mm moves the lightest feasible width up 0.5 mm (about 1 g, 3%); stylised, preliminary.
- Do the isolated feasible pockets of the 2 mm laser-cut bracket survive mesh refinement?The isolated feasible pockets below w = 15 mm at the 2 mm laser-cut gauge vanish at 2.0 and 1.5 mm element size, and the smallest feasible w moves up (14.4 to 15.6 mm at r = 14 mm); stylised, preliminary.
- Is the narrow 2 mm laser-cut bracket region a mesh artefact?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.
- 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.
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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.