forked from 1b-agent/fieldcraft-upstream
jyvikoandClaude Opus 5.5
cf8ed71e4f
file.sample rubber-seal: a gasket ring of hybrid hex8 elements in four mapped quarter blocks, squeezed 2.5 mm between plates bonded to it (nonlinear static, Mooney-Rivlin rubber). Its test frees the plates and matches the closed form for incompressible uniaxial compression within 3 %, and bounds the bonded ring's extra stiffness. The plates are prescribed displacements until implicit contact (#161) can press it into a groove. Closes #163 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01UhhZMBTviDQxZvwnyP89fo
49 lines
3.0 KiB
Markdown
49 lines
3.0 KiB
Markdown
# Examples
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Every example is a built-in sample: open it from **File ▸ Samples** (or the start screen), with
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`fieldcraft --sample NAME`, or with the `file.sample` command (`{"name": "drop-test"}`), then
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press **Solve** (`solve.run`). Each opens fully defined — geometry, mesh, materials, boundary
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conditions, loads and steps — in mm, t, s, N and MPa, and opens and solves within half a minute. The geometry is our
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own: SolidCraft scripts run when the sample opens (a recipe from [`tests/corpus`](../tests/corpus)
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or one written in `crates/engine/src/sample.rs`). Each sample has a test in
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`crates/engine/src/sample.rs` that opens it, checks it clean, solves it and holds its result to
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the check given below.
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## Drop test (`drop-test`)
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An aluminium L-bracket (60 × 40 mm foot, 50 mm upright, 8 mm thick, R6 fillet) falls 2 m onto a
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rigid floor tilted 15°, so the end of its foot strikes first. Explicit dynamics for 1 ms with
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gravity: 1 911 swept hex8 elements (one-point, stiffness hourglass control), bilinear plasticity
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(yield 240 MPa), the floor a rigid wall. About 8 400 increments, a few seconds.
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**Look at:** the frames from the strike (Results ▸ Frame): the compression wave leaves the
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struck corner and the upright's inertia bends the fillet, where von Mises peaks near 120 MPa —
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below yield, so the drop leaves no permanent set. The energies plot shows the kinetic energy
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turning into vibration with a balance under 0.01 %.
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**Check:** the mass equals ρ V of the bracket (0.5 %); it meets the floor at √(2 g h) =
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6.26 m/s, with ½ m v² = 1 748 mJ of kinetic energy (1 %); energy is conserved (balance < 1 %);
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by 1 ms the floor has taken about half its downward momentum.
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## Rubber seal (`rubber-seal`)
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A rubber gasket ring (20 mm inside radius, 30 mm outside, 10 mm high) squeezed 2.5 mm (25 %)
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between two plates bonded to it. Generic rubber, E = 6 MPa, ν = 0.49, Mooney–Rivlin with
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C01 = 0.2 MPa; 1 000 hybrid (u–p) hex8 elements in four mapped quarter blocks. Nonlinear static
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with large deformation: Newton–Raphson in nine increments, under a second.
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**Look at:** the deformed shape at scale 1 — the free inner and outer walls bulge out, and
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von Mises peaks (about 7 MPa) where the bulge meets the bonded plates. Results ▸ Increment steps
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through the converged increments.
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**Check:** the same ring between frictionless plates compresses evenly, and its force matches
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the closed form for an incompressible Mooney–Rivlin solid in uniaxial compression,
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P = 2 (λ − λ⁻²)(C10 + C01/λ) per original area: 3 430 N against 3 466 N (within 3 %). Bonded,
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the bulge makes it stiffer (shape factor 0.5): 6 518 N, held between 1.05 and 2.5 times the
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frictionless force. The groove and the plates are prescribed displacements today; with implicit
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contact (#161) the ring will be pressed by contact against a groove.
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