Source: https://guthlabs.ai/docs/instruments/bolted-joint-strength-calculator/implementation/

instrument implementation / implementation-contract

# Bolted Joint Strength Calculator implementation

A source-bound implementation contract for Bolted Joint Strength Calculator; 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**: t7-069

**Effect**: Computation or source lookup only

## Input and validation requirements

The stiffness-ratio calculation divides by kb + km and becomes undefined when the stiffness sum is zero; the instrument should reject that input. The specification also lacks the torque coefficient or a torque lookup, so recommended torque is undefined for torque-based tightening inputs.

## 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": {
    "bolt": "M10 x 1.5",
    "grade": "ISO property class 8.8",
    "applied_axial_load_N": 20000,
    "tightening_method": "nut-factor estimate",
    "K": 0.2,
    "nominal_diameter_m": 0.01,
    "kb_N_per_mm": 100000,
    "km_N_per_mm": 900000
  },
  "expected_outputs": {
    "tensile_stress_area_mm2": 58,
    "proof_strength_MPa": 600,
    "preload_N": 26100,
    "C": 0.1,
    "bolt_load_N": 28100,
    "bolt_tensile_stress_MPa": 484.482759,
    "proof_based_SF": 1.238434,
    "separation_load_N": 29000,
    "remaining_clamp_force_N": 8100,
    "conditional_torque_N_m": 52.2
  },
  "reference_data": {
    "tensile_stress_area_mm2": 58,
    "proof_strength_MPa": 600,
    "source_convention": "ISO 898-1 standard table values for M10 property class 8.8; widely tabulated standard value"
  },
  "working": "At=58.0 mm² and Sproof=600 MPa. Fi=0.75×600×58.0=26100 N. C=100000/(100000+900000)=0.100000. Incremental bolt load=C×P=0.1×20000=2000 N. Total bolt load=26100+2000=28100 N. σ=28100/58.0=484.482759 MPa. SF=600/484.482759=1.238434. Psep=Fi/(1-C)=26100/0.9=29000 N. Remaining clamp force=Fi-(1-C)P=26100-0.9×20000=8100 N. Conditional torque T=K×Fi×d=0.2×26100×0.01=52.2 N·m."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/bolted-joint-strength-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/bolted-joint-strength-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/bolted-joint-strength-calculator/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-tranche7/tranche7-results.json`