Von Mises / Tresca Failure Criteria Checker mechanism

Model scope

The stated Von Mises and Tresca equations are standard under the listed assumptions, and the honest label appropriately limits the tool to ductile-material yield criteria. Review is required to define the 2D-versus-3D selection, explicitly add SF_vm=σy/σ_vm, define zero-safety-factor behavior, and specify yield-strength-table context.

• The Von Mises safety-factor formula SF_vm=σy/σ_vm is not explicitly provided, although SF_vm is listed as an output.
• The choice between the 2D and 3D Von Mises formulas is not specified as an input or decision rule. The 2D formula is valid for plane stress with the omitted principal stress equal to zero.
• Tresca requires the maximum and minimum of all three principal stresses; the specification should explicitly state that σmax=max(σ1,σ2,σ3) and σmin=min(σ1,σ2,σ3).
• The yield-strength table is underspecified: material, temperature, heat treatment, and applicable yield definition are not identified.

Units and conventions

• All principal stresses and σy must use the same stress unit, such as MPa, ksi, or psi.
• For the 2D formula, the stress state is assumed to be plane stress with σ3=0.
• σy is assumed to be a positive uniaxial yield stress for an isotropic ductile material.
• Safety factors are dimensionless; equivalent stress and yield strength retain the selected stress unit.

Inspectable vector

One of 4 source-bound review vectors:

{
  "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."
}

Failure boundary

BREAK_CLAIMED · SELF_FLAGGED

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.

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
• BOUNDARY_HAZARD_CATALOG.json