Source: https://guthlabs.ai/docs/instruments/thermal-stress-calculator/

instrument / verified-clean

# Thermal Stress Calculator

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Status: **VERIFIED_CLEAN**Lifecycle: **verified-clean**

## Inspectable records

[01**Overview**Purpose and lifecycle](<https://guthlabs.ai/docs/instruments/thermal-stress-calculator/>)[02**Mechanism**Method and assumptions](<https://guthlabs.ai/docs/instruments/thermal-stress-calculator/mechanism/>)[03**Implementation**Binding and validation](<https://guthlabs.ai/docs/instruments/thermal-stress-calculator/implementation/>)[04**Qualification**Evidence and errata](<https://guthlabs.ai/docs/instruments/thermal-stress-calculator/qualification/>)

## Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

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

**Tranche**: tranche-4

**Evidence ID**: t4-046

**Ledger rows**: 1

No ledger note is attached.

## Review findings

The honest label correctly states full restraint and linear elasticity but should also disclose the signed-stress convention or explicitly label the result as a stress magnitude, plus the uniform-temperature, isotropic, constant-property, and one-dimensional-restraint assumptions.

### Formula and scope findings

- σ=EαΔT is correct for the magnitude of stress under uniform temperature change and complete axial restraint, assuming linear elasticity and constant isotropic properties.

- For a signed stress with tensile stress positive, the standard relation is σ=-EαΔT: heating produces compression and cooling produces tension. The specification does not state whether σ_thermal is signed or a magnitude.

- The model does not state the required assumptions of uniform temperature, isotropic material behavior, temperature-independent E and α over the range, and one-dimensional/full restraint in the expansion direction.

### Unit assumptions

- E must be entered in pascals (Pa) for σ_thermal to be returned in pascals.

- α must be entered in reciprocal kelvins (1/K) or reciprocal degrees Celsius (1/°C). Temperature differences in kelvins and degrees Celsius have the same numerical value.

- ΔT must be a temperature difference, defined as final temperature minus initial temperature; it must not be an absolute temperature.

- The CTE table must provide α appropriate to the material and temperature range; using a single constant α is an approximation.

## Boundary hardening

**BREAK_CLAIMED** · SELF_FLAGGED

The extreme finite inputs produce a mathematical result of 10^613 Pa, which overflows JavaScript double-precision arithmetic to Infinity. The instrument should reject or range-check nonphysical/extreme inputs rather than present Infinity as a normal stress result.

## Errata and corrections

No applied erratum is attached to this unique-name record.

## Inspectable example

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

````
{
  "inputs": {
    "E": 200000000000,
    "alpha": 0.000012,
    "delta_T": 50,
    "units": "E in Pa; alpha in 1/K; delta_T in K"
  },
  "expected_outputs": {
    "sigma_thermal_Pa": 120000000,
    "sigma_thermal_MPa": 120
  },
  "working": "σ = E × α × ΔT\n= 200,000,000,000 × 0.000012 × 50\n= 2,400,000 × 50\n= 120,000,000 Pa\n= 120 MPa\nLiteral formula result is positive; physically, under tensile-positive convention, restrained heating corresponds to -120 MPa compression."
}
````

## Related workflows

[Beam & Column Structural Benchthermal loads](<https://guthlabs.ai/docs/instrument-workflows/structural-bench/>)

## Sources and evidence

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

- `VERIFIED_LEDGER.json · VERIFIED_CLEAN`

- `evidence-tranche4/tranche4-results.json`

- `BOUNDARY_HAZARD_CATALOG.json`