A small model has three supports. Node 0 has a full anchor. Node 1 has a translational spring of 250.0 N/m in Y. Node 2 has an imposed rotation of 0.015 rad about Z. How many degrees of freedom are rigidly restrained? Does the spring retain its elastic behavior instead of becoming a rigid restraint?

This page preserves a recorded benchmark and its expected values. The dated run below is not a new run of the current product.

This benchmark prepares boundary entries without solving a moving spring base.

Software boundary check. The recorded test exercises a benchmark crate. It does not exercise the desktop product route.

1.Inputs.

Illustrative values, taken from no standard and chosen so the arithmetic can be followed by hand. Most do not describe a real pipe; read them in any consistent set of units.

2.Method.

The anchor holds all six freedoms at its node. The imposed rotation fixes one more freedom at a known value. The spring resists movement elastically and does not join the list of rigid restraints.

3.Results.

The case record describes these checks:

• Boundary preparation completes without blocking.
• Seven freedoms are rigidly restrained.
• Exactly one spring is recorded, with a stiffness of 250.0 N/m.
• Exactly one imposed displacement is recorded, with a value of 0.015 rad.

What it shows. Checks the loads or boundary conditions prepared for the solver against a hand calculation. No system is solved.

Path exercised. The benchmark calls the solver’s components directly: elements, loads, frame solver and stress recovery. It does not go through the program’s own model-to-solve path.

Agreement. Each computed value must match the reference within an absolute difference of 1.0 × 10⁻⁹ in the case’s own units. Counts and structural outcomes must match exactly. Long values are shown here to seven significant figures; the tests compare the full values in the record.

4.Recorded command.

This command belongs to the archived source at 462f66975d36cd10d5b8455193ada9517d28d353. Use a checkout of that exact revision. This edition did not run the command. The recorded result does not establish current product support.

git checkout --detach 462f66975d36cd10d5b8455193ada9517d28d353
cd projects/chirality-piping
cargo test --manifest-path validation/benchmarks/mechanics/Cargo.toml support_boundary_fixture_prepares_mixed_supports

Hand calculation: validation/hand_calcs/mechanics/support_boundary_mixed.md. Test record, with the recorded run of 2026-07-10: mech-support-boundary-mixed.md.