Fatigue Crack Inspection Scheduler

Paris-law crack growth: tracks crack length per load cycle and schedules inspection before it reaches critical size. The model behind aircraft & bridge maintenance windows.

Category	Structural Engineering
Template ID	fatigue-crack-inspection
Definition	fatigue_crack_inspection v1.0
States	4 (initial: nominal; terminal: repaired)
Transitions	3
Operators composed	MATERIAL_STRENGTH, STRESS_PRINCIPAL, KO42
Audit clock	on · tick rate 1

What it's for

• Aircraft airframe inspection
• Bridge fatigue management
• Rotor / shaft life-ing

States

State	Role
nominal	initial
crack_initiated	intermediate
inspect_now	intermediate
repaired	terminal

Transitions

From	To	Operator	Fires when	Proof	Trigger / actions
nominal	crack_initiated	STRESS_PRINCIPAL	input.crack_length_mm > input.detectable_mm	required	—
crack_initiated	inspect_now	MATERIAL_STRENGTH	input.crack_length_mm > input.critical_mm * input.inspection_margin	required	—
inspect_now	repaired	KO42	input.repair_done == true	required	—

Operators it composes

Each transition fires a registry operator through the master equation (compute → prove → verify). This template composes:

• MATERIAL_STRENGTH
• STRESS_PRINCIPAL
• KO42

Browse the operators at /operators/; the building blocks a transition calls are the framework's protocols. KO42 is the always-on substrate operator; physics operators carry proof_required: true, so each fire runs the full compute → prove → verify path and lands a verifiable proof digest on your entangled state.

Deploy it

Inspect the full definition, then deploy it onto your state machine. Every fire is Zeqond-stamped onto your entangled state.

# 1. Inspect — the full definition (states, transitions, operators) as served
curl -sS https://zeqsdk.com/api/contracts/templates/fatigue-crack-inspection

# 2. Deploy onto your machine (auth: session; body carries your machine slug)
curl -sS -X POST https://zeqsdk.com/api/contracts/templates/fatigue-crack-inspection/deploy \
  -H "Content-Type: application/json" \
  -b "<your session cookie>" \
  -d '{"slug":"<your-machine>"}'
# → 201 { "ok": true, "contract": { "id": "…", "currentState": "nominal", … },
#         "template_id": "fatigue-crack-inspection" }

The deploy path runs the same two-stage validation as the canonical create route (ContractDefinitionSchema.parse + validateContractDefinition against the live registry), writes the creation row onto your entangled state, and schedules the first fire. From there, drive transitions with POST /api/chain/<your-machine>/contracts/<id>/transition or let any triggers fire them autonomously.

Next

• Contract IDE — author, preview, and deploy contracts (this template is in the Templates tab).
• State Contracts — the full contract model: conditions, triggers, pre/post actions, lifecycle.
• Templates Library — every ready-to-deploy contract, grouped by category.
• Protocols — the named building blocks a transition composes.