Stress Concentration Factor Lookup

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-7

Evidence ID

t7-002

Ledger rows

1

No ledger note is attached.

Review findings

The core formula is standard, but the instrument needs the exact Peterson chart edition or digitized dataset, geometry definitions, interpolation policy, extrapolation policy, ratio validity ranges, and nominal-stress convention before it can be marked PASS. The four vectors use explicit reference fragments so their outputs are independently computable.

Formula and scope findings

• The relationship σmax = Kt·σnom is correct for linear-elastic elastic stress concentration, provided Kt and σnom use the same load case and nominal-stress convention.
• Kt is geometry- and loading-specific; the specification does not define the exact Peterson geometry, boundary conditions, or nominal section used for each feature.
• The lookup/curve-fit validity ranges for r/d, D/d, d/W, plate thickness, and 2D versus 3D geometry are unspecified.
• Kt is an elastic stress-concentration factor and must not be presented as a fatigue notch factor Kf or as an elastic-plastic peak-stress prediction.
• The actual digitized Peterson table or polynomial coefficients are not supplied, so the implementation cannot be fully verified against its claimed source.

Unit assumptions

• Stress inputs and σmax use the same units, here MPa.
• All geometric ratios are dimensionless and must be formed from lengths in consistent units.
• For finite-width plates, σnom is the nominal far-field tensile stress based on the gross section unless explicitly stated otherwise.
• The calculations assume homogeneous, isotropic, linear-elastic material, small deformation, and the plane-stress chart convention unless the source chart specifies another condition.
• For the elliptical-hole case, a is the major semi-axis and b is the minor semi-axis; the Inglis result applies to an effectively infinite plate under uniaxial tension.

Boundary hardening

BREAK_CLAIMED · SELF_FLAGGED

The stated instrument depends on Peterson chart data or curve-fit coefficients that are not provided. Consequently, valid finite geometries such as r/d = 0.1 and D/d = 2 cannot produce numerical Kt values from this specification alone. The instrument also has explicit failure points at r/d = 0 and d = 0 that require rejection or an unbounded/undefined result.

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": {
    "feature_type": "circular hole in effectively infinite plate",
    "load_type": "uniaxial tension",
    "hole_diameter_mm": 20,
    "plate_width_mm": "infinite",
    "sigma_nom_MPa": 100
  },
  "expected_outputs": {
    "Kt": 3,
    "sigma_max_MPa": 300
  },
  "reference_data": {
    "geometry": "circular hole, d/W -> 0",
    "Kt": 3,
    "source_convention": "Peterson's Stress Concentration Factors, standard circular-hole infinite-plate tension entry; widely tabulated standard value"
  },
  "working": "1. Boundary ratio: d/W -> 0, so use the infinite-plate row. 2. Kt = 3. 3. σmax = Kt·σnom = 3·100 MPa = 300 MPa."
}

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-tranche7/tranche7-results.json
• BOUNDARY_HAZARD_CATALOG.json