jyvikoandClaude Opus 5.5 a953dc6216 solver, model: arc-length control with critical points from the inertia ...

NonlinearStatic.arc_length {constraint, max_load_factor, displacement_limit}: Riks–Crisfield
arc-length increments (cylindrical or spherical arc, tangent predictor signed by the angle
criterion, the constraint's quadratic root chosen by the angle with the last iterate), arcs
grown, shrunk and cut back as increments are. The converged state's tangent is factored for the
next predictor (LDLᵀ when indefinite); its negative eigenvalues are recorded per increment and
changes in their count are reported as limit or bifurcation points. Ends at the maximum load
factor, a displacement limit or the increment cap. Abaqus *STATIC, RIKS; LS-DYNA refuses it by
name; forms gain the arc-length group. A shallow arch of hex20 snaps through on the closed-form
path (1.9 %), both limit points found, inertia 0 → 1 → 0 between them.

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01UhhZMBTviDQxZvwnyP89fo

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..

bcs.rs

FEM foundation B: heat transfer and thermal stress (solids, 2D, explicit), coupled temperature–displacement, solve.heat (#45)

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check.rs

solver, model, engine: linear buckling steps

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constraints.rs

1D elements I: trusses (rod2, rod3), point masses, rotary inertia, springs and dashpots (#38)

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contact.rs

model: contact pairs, general contact and Coulomb friction, mapped by the deck writers

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discrete.rs

1D elements I: trusses (rod2, rod3), point masses, rotary inertia, springs and dashpots (#38)

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fluids.rs

Explicit X2: large deformation, J2 and Johnson-Cook plasticity, damage and erosion (M10)

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geometry.rs

The .modelcraft file, undo/redo on the journal, atomic saves and autosave recovery (M3) (#21)

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lib.rs

solver, model: arc-length control with critical points from the inertia

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loads.rs

FEM foundation B: heat transfer and thermal stress (solids, 2D, explicit), coupled temperature–displacement, solve.heat (#45)

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materials.rs

fem, model: Mooney-Rivlin and Yeoh hyperelasticity in nonlinear steps

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mesh.rs

Tet mesh quality: one validity criterion, Delaunay refinement, ODT, Klingner–Shewchuk, tet10

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nodal.rs

fem: finite-strain material point, total Lagrangian elements and follower pressure

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sections.rs

2D elements: plane stress, plane strain and axisymmetric sections on the DOF framework; mesh.planar (M4) (#39)

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sets.rs

model: contact pairs, general contact and Coulomb friction, mapped by the deck writers

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steps.rs

solver, model: arc-length control with critical points from the inertia

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units.rs

Model definition: sets by geometry name, materials, sections, couplings, BCs, loads, steps, check (#16)

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