Source: https://guthlabs.ai/docs/instruments/weld-group-line-property-calculator/implementation/

instrument implementation / implementation-contract

# Weld Group (Line) Property Calculator implementation

A source-bound implementation contract for Weld Group (Line) Property Calculator; 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**: t5-053

**Effect**: Computation or source lookup only

## Input and validation requirements

An empty weld pattern has total line length zero, so centroid, Iu, and Ju about that centroid are undefined. The calculator must reject the input rather than return numeric values or propagate NaN silently.

## 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": {
    "units": "mm",
    "u_axis": "x",
    "segments": [
      {
        "start": [
          0,
          0
        ],
        "end": [
          100,
          0
        ]
      }
    ]
  },
  "expected_outputs": {
    "centroid": [
      50,
      0
    ],
    "Iu_mm3": 0,
    "Ju_mm3": 83333.333333
  },
  "working": "Segment length L=100 mm. Centroid=(0+100)/2,(0+0)/2=(50,0) mm. Iu=∫y² ds=100×0²=0 mm³. Ju=∫(x-50)²dx=100³/12=1000000/12=83333.333333 mm³."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/weld-group-line-property-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/weld-group-line-property-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/weld-group-line-property-calculator/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-tranche5/tranche5-results.json`