Stress Concentration Factor Lookup mechanism

Model scope

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.

• 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.

Units and conventions

• 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.

Inspectable vector

One of 4 source-bound review vectors:

{
  "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."
}

Failure boundary

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.

Other records

Sources and evidence

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

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