Clutch/Brake Torque Capacity Calculator

Inspectable records

Ledger state

The current ledger marks this instrument verified with errata that must be applied at binding time.

Area

Mechanical, Civil & Structural Engineering — Statics/Dynamics, Strength of Materials, Machine Design, Civil, HVAC, Vibration

Tranche

tranche-5

Evidence ID

t5-084

Ledger rows

1

No ledger note is attached.

Review findings

The arithmetic and both stated formulas are standard under their respective assumptions. Verdict is NEEDS_REVIEW because the wear-model selection and the exact meaning of n are not fully specified. The third vector exposes a unit-conversion trap; its corrected result is 56.25 N·m, not 506.25 N·m.

Formula and scope findings

• The formulas are standard and correct only when n means the number of active friction surfaces and F means the total axial clamping force acting on the friction pack.
• The specification provides both uniform-wear and uniform-pressure formulas but does not define an input or rule for selecting which wear model to use; the computed result is therefore ambiguous.
• The common alternative convention counts friction pairs rather than friction surfaces, so the definition of n must be explicit in the interface and documentation.

Unit assumptions

• μ is dimensionless.
• F is in newtons.
• ro and ri are radii, not diameters, and must use the same length unit.
• The resulting torque T is in force-length units; with F in newtons and radii in metres, T is in N·m.
• For the uniform-wear model, r_eff=(ro+ri)/2 assumes ri<ro and a physically valid annular friction surface.
• For the uniform-pressure model, r_eff=(2/3)(ro³-ri³)/(ro²-ri²) assumes ri<ro and consistent length units.

Boundary hardening

BREAK_CLAIMED · SELF_FLAGGED

The uniform-pressure formula becomes undefined when ro=ri because its denominator ro^2-ri^2 is zero. The instrument should reject that geometry rather than return a numeric torque. Additional hazards are the physically invalid n=0 boundary, the unspecified branch-selection criterion, and the sign convention for axial force and torque.

Errata and corrections

Tranche errata

Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

{
  "inputs": {
    "mu": 0.3,
    "F_N": 4000,
    "ro_m": 0.15,
    "ri_m": 0.08,
    "n_friction_surfaces": 2,
    "wear_model": "uniform_wear"
  },
  "expected_outputs": {
    "T_Nm": 276
  },
  "working": "r_eff=(ro+ri)/2=(0.15+0.08)/2=0.23/2=0.115 m. T=n·μ·F·r_eff=2·0.3·4000·0.115=0.6·4000·0.115=2400·0.115=276 N·m."
}

Related workflows

No source-defined multi-instrument workflow membership is recorded.

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json · VERIFIED_WITH_ERRATA
• evidence-tranche5/tranche5-results.json
• BOUNDARY_HAZARD_CATALOG.json