Factor of Safety / Allowable Stress Calculator

Inspectable records

Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Area

Mechanical, Civil & Structural Engineering — Statics/Dynamics, Strength of Materials, Machine Design, Civil, HVAC, Vibration

Tranche

tranche-5

Evidence ID

t5-185

Ledger rows

1

No ledger note is attached.

Review findings

The two stated formulas are arithmetically standard under explicit strength-selection and unit-consistency assumptions, but the spec is incomplete because it claims required-section sizing without a sizing formula and does not define the yield-versus-ultimate criterion. The empty honest_label should be replaced with a limitation statement identifying this as a basic stress-ratio calculator, not a complete structural or machine-design sizing/code-compliance tool.

Formula and scope findings

• SF=σ_strength/σ_actual is the standard basic factor-of-safety formula when σ_strength is explicitly selected as yield or ultimate strength and both stresses use the same basis and units.
• σ_allow=σ_yield/SF is correct for an allowable stress based on yield strength; using ultimate strength instead requires an explicitly selected design criterion and may not be appropriate for ductile-material yielding checks.
• The claimed 'required section' computation has no formula or required inputs for load, geometry, section properties, or stress relationship, so that capability is unspecified and cannot be verified.
• The spec does not unambiguously define whether the strength input is yield strength or ultimate strength, nor which criterion is the default.

Unit assumptions

• σ_strength and σ_actual must represent the same stress type and use compatible units; the units cancel in SF.
• For σ_allow, σ_yield and target SF must be supplied with a positive target SF; σ_allow has the same stress units as σ_yield.
• No automatic conversion between Pa, kPa, MPa, psi, or other stress units is stated.
• Stress sign conventions and whether tensile, compressive, shear, or equivalent stress is intended are unspecified.

Boundary hardening

BREAK_CLAIMED · SELF_FLAGGED

A zero target safety factor produces division by zero and must be rejected. The signed-stress probe also exposes a convention hazard: literal arithmetic gives a negative safety factor, whereas the usual engineering interpretation uses stress magnitude.

Errata and corrections

No applied erratum is attached to this unique-name record.

Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

{
  "inputs": {
    "mode": "SF",
    "strength_type": "yield",
    "strength": 250,
    "strength_unit": "MPa",
    "actual_stress": 100,
    "actual_stress_unit": "MPa"
  },
  "expected_outputs": {
    "SF": 2.5
  },
  "working": "SF = σ_yield / σ_actual = 250 MPa / 100 MPa = 2.5. The MPa units cancel."
}

Related workflows

No source-defined multi-instrument workflow membership is recorded.

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json · VERIFIED_CLEAN
• evidence-tranche5/tranche5-results.json
• BOUNDARY_HAZARD_CATALOG.json