Public evidence

mechanical.statics.section_modulus

Machine-checked verification for calculation version 1.0.0 · tier engine_tested

Open calculator API Capability Download JSON MCP Review policy

Verification

6/6 calculation tests · Production surface contract 6/6

Golden tests 2 / 2
Boundary tests 4 / 4
Property tests 0 / 0
Production surface contract 6 / 6
Engine tested Yes
Source checked Yes
Artifact integrity PASS
Production attestation Embedded snapshot: unpublished · Build schema 1.0.0 ready · Semantic contract ✓ · Attestation report not published on origin · Live production status STALE (3 capabilities; 189 remain CURRENT) @ 2026-09-23T10:40:38.140Z
Semantic contract PASS
Evidence attested at 2026-09-23T02:27:54.588Z
Last production check 2026-09-23T02:27:54.588Z
Public / cache —
Origin —
Supplemental domain review Not performed
Named expert review Not performed

release artifacts aligned PASS
schema output required declared PASS
schema valid input executes PASS
engine success output validates schema PASS
schema rejects incomplete input PASS
rest success payload validates schema PASS

Fingerprint sha256:117e15ea5bb8b757f63e45efbdbdd1a80ef773d9e0745233eed1025076b817b2

Input schema sha256:ed2807627c577687faf96f87490498e214c45a3c31ca37389075874331a69f67 · Output schema sha256:14438c93c6ef06a3f75af933311ee734598a7240873f86d85f461cd2154fa652 · Build-time SHA-256 digests prove published artifacts agree with each other (release_integrity.scope=workspace). Production attestation GETs canonical URLs twice (public/cached view and origin), including Capability HTML, via npm run attest:production --write (published at /.well-known/calculatorx-production-attestation.json) and fails if the public Capability page advertises a different calculation_version. This is artifact consistency, not an independent immutable release log.

Build & scope

Engine identity and declared limitations.

Tool: section-modulus
Engine: section-modulus
Engine build: 2026-09-23
Evidence core: 2026-09-23T09:48:44.481Z
Rendered: 2026-09-23T10:57:00.182Z
Last reviewed: —

Limitations

Sx = Ix/cy and Sy = Iy/cx about axes parallel to x and y
cx and cy are distances from the composite centroid to the extreme fiber
A blank distance omits that modulus
Negative area is a hole
Not bending stress, plastic modulus, principal-axis modulus, or beam deflection

Sources

Standards and references supporting this tool specification. Methods are listed separately — they are algorithms, not bibliographic sources.

Hibbeler, Engineering Mechanics: Statics — Moments of inertia
Supports: Elastic section modulus S = I/c, with c the distance from the centroid to the extreme fiber

Published checks

Golden, boundary, and property cases included in this evidence build.

ID	Kind	Status	Detail
`golden-both`	golden	pass	Expected Ix=16 · Iy=4 · Sx=8 · Sy=4 · area=4 · x_bar=0 · y_bar=0 · model=section_modulus · Actual n=1 · model=section_modulus · area=4 · x_bar=0 · y_bar=0 · Ix=16 · Iy=4 · Sx=8
`golden-sx`	golden	pass	Expected Ix=4 · Sx=4 · y_bar=1 · Actual n=2 · model=section_modulus · area=2 · x_bar=0 · y_bar=1 · Ix=4 · Iy=0 · Sx=4
`boundary-hole`	boundary	pass	Expected area=3 · Ix=6 · Iy=6 · Sx=6 · Sy=6 · Actual n=2 · model=section_modulus · area=3 · x_bar=0 · y_bar=0 · Ix=6 · Iy=6 · Sx=6
`boundary-empty`	boundary	pass	Expected MISSING_REQUIRED_INPUT · Actual MISSING_REQUIRED_INPUT
`boundary-fiber`	boundary	pass	Expected VALUE_MUST_BE_POSITIVE · Actual VALUE_MUST_BE_POSITIVE
`boundary-negative`	boundary	pass	Expected INVALID_INPUT · Actual INVALID_INPUT