Source: https://guthlabs.ai/docs/instruments/von-mises-tresca-failure-criteria-checker/implementation/

instrument implementation / implementation-contract

# Von Mises / Tresca Failure Criteria Checker implementation

A source-bound implementation contract for Von Mises / Tresca Failure Criteria Checker; 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**: t4-130

**Effect**: Computation or source lookup only

## Input and validation requirements

The criteria generate division-by-zero results for equal principal stresses, and the zero-yield-strength boundary requires explicit rejection. A robust checker must detect both conditions instead of emitting ordinary numeric safety factors.

## 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": {
    "mode": "2D_plane_stress",
    "sigma1": 120,
    "sigma2": -40,
    "sigma_y": 250,
    "stress_unit": "MPa"
  },
  "expected_outputs": {
    "sigma_vm": 144.222051,
    "SF_vm": 1.733438,
    "SF_tresca": 1.5625
  },
  "working": "σ_vm=√(σ1²−σ1σ2+σ2²)=√(120²−(120×−40)+(−40)²)=√(14400+4800+1600)=√20800=144.222051 MPa. SF_vm=σy/σ_vm=250/144.222051=1.733438. τmax=(σmax−σmin)/2=(120−(−40))/2=160/2=80 MPa. SF_tresca=σy/(2τmax)=250/(2×80)=250/160=1.5625."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/von-mises-tresca-failure-criteria-checker/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/von-mises-tresca-failure-criteria-checker/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/von-mises-tresca-failure-criteria-checker/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-tranche4/tranche4-results.json`