SWBPIPE · The open manual
Part VI · VerificationVI–A3

Part VI

Verification

A. System benchmarks  ·  A restrained bend with pressure, heat and weight

An L line has anchors at A and D. A realized circular bend joins the straight pipes.

Internal pressure is 5.0e6 Pa. Both closures transfer their cap loads to the pipe. Uniform heating and downward self-weight act on every member.

The independent reference uses the direct unit-load method. The current test calls the captured product API in both solver modes and document versions.

This case compares independent numerical values. It does not exercise desktop authoring, the native CLI or report export.

The reference matches small-strain linear elasticity with homogeneous isotropic material and a user-entered bend flexibility factor.

The formulation excludes flow momentum, transient loads, Bourdon bend opening, pressure stiffening and ovalization.

The frozen expectations predate this refresh. The date below records a new product comparison, not a new reference derivation.

The focused test passed on 2026-10-12: one test passed, none failed. Its assertions cover 316 reference, mode and document-version configurations.

Source 1. Source 2.

1.Inputs.

The table gives the declared reference inputs. Units are stated for each quantity.

QuantitySymbolValue
Node A coordinatesA(0.0, 0.0, 0.0) m
Node B coordinatesB(3.0, 0.0, 0.0) m
Node C coordinatesC(3.25, 0.25, 0.0) m
Node D coordinatesD(3.25, 4.25, 0.0) m
Bend radiusR0.25 m
Bend flexibility factork2
Outside diameterOD0.1683 m
Nominal wallt0.00711 m
Mill tolerancem0.000889 m
Elastic modulusE2.0e11 Pa
Poisson rationu0.3
Internal pressurep5.0e6 Pa
Terminal closure transferA and Dtransfers_to_wall
SupportAA and D anchored; all six freedoms restrained
Thermal expansion coefficientalpha1.2e-5 1/°C
Uniform temperature changedelta T50 °C
Uniform self-weightw4.309503e+2 N/m; global −Z

2.Method.

The reference integrates axial, torsional and bending flexibility over the whole line. It does not use a curved-element stiffness matrix.

Pressure caps produce wall tension. The pressure eigenstrain includes Poisson contraction on each straight and arc.

Positive wall force means tension. The effective axial force is wall force minus pressure times bore area.

The reference uses meters and pascals. The product converts translations to millimeters and bending or torsion stresses to megapascals. Axial membrane stress stays in pascals.

The reference solves six end redundants through a flexibility matrix. The end conditions prevent free pressure and thermal growth.

Weight acts per unit centerline length, including arc length. The user-entered flexibility factor is 2 in both bend planes.

t_eff = 0.00711 − 0.000889 = 0.006221 m(1)
N_w = S + p A_i; sigma_m = N_w / A_s(2)

3.Results.

Selected signed reactions and bend station values in SI units
QuantityExpected
support:A Fx8.986626e+2 N
support:A Fy1.458807e+3 N
support:A Fz1.667875e+3 N
support:A Mx-3.074178e+2 N·m
support:A My-2.707374e+3 N·m
support:A Mz2.696923e+3 N·m
support:D Fx-8.986626e+2 N
support:D Fy-1.458807e+3 N
support:D Fz1.518011e+3 N
support:D Mx-2.250201e+3 N·m
support:D My-4.353565e+2 N·m
support:D Mz-1.775117e+3 N·m
Bend midspan N_w9.372636e+4 N
Bend midspan S-1.666983e+3 N
Bend midspan M_y-5.28203e+2 N·m
Bend midspan M_z1.871577e+3 N·m
Bend midspan sigma_m2.958864e+7 Pa
Bend midspan sigma_b_y-4.266928e+6 Pa
Bend midspan sigma_b_z1.511897e+7 Pa
Bend midspan tau_t-2.43936e+5 Pa

The case record describes these checks:

  • The test compares every valued reference case in both sparse_interactive and dense_scrutiny modes. Each document runs as 0.3.0 and 0.4.0.
  • The comparisons include node movement, support reactions, station forces and stresses, end actions and terminal cap transfers.
  • The test requires the pressure integrity verdict and checks required row absences on arcs.
  • The wall end action follows the end tangent. The arc elastic end-force rows use the chord frame. These quantities have different meanings.

What it shows. Compared with an independent reference calculation.

Path exercised. The captured product API, in both solver modes and both document versions. The comparison does not exercise desktop authoring, the native CLI or report export.

Agreement. The test requires |observed − expected| ≤ 1e-9 × max(|expected|, zero_scale(group)). The frozen reference defines each group floor. Exact unit conversion precedes comparison. Long values are shown here to seven significant figures; the tests compare the full values in the record.

For the student

Both anchors resist growth and weight. Wall force and effective axial force differ by pA_i. Signed bending and torsion components remain separate.

4.Recorded command.

This command belongs to the archived source at a72f994d89d901b185116e6565bacb201b69e151. 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 a72f994d89d901b185116e6565bacb201b69e151
cd projects/chirality-piping
cargo test --offline --locked --manifest-path core/product_physics/Cargo.toml --test t4_u2_pressure_references i7_valued_cases_match_in_both_modes_and_document_versions -- --exact

Execution record: 2026-10-12.

Reference calculation: validation/references/t4_i7/u2_reference_cases.json. Test source for the execution of 2026-10-12: t4_u2_pressure_references.rs.

Contents · Part VI · The program: swbpipe.com · MIT licence