Von Mises / Tresca Failure Criteria Checker implementation

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

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