Source: https://guthlabs.ai/docs/instruments/stress-concentration-factor-lookup/implementation/

instrument implementation / implementation-contract

# Stress Concentration Factor Lookup implementation

A source-bound implementation contract for Stress Concentration Factor Lookup; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

**Record owner**: Guth Instruments

**Lifecycle**: verified-clean

**Evidence ID**: t7-002

**Effect**: Computation or source lookup only

## Input and validation requirements

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.

## Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

## Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

````
{
  "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."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/stress-concentration-factor-lookup/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/stress-concentration-factor-lookup/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/stress-concentration-factor-lookup/qualification/>)

## 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`