Developing Approaches for Certification of Uninspectable Fracture Critical AM Components

Introduction
- Human-rated spaceflight hardware is subject to the Fracture Control requirements in NASA-STD5019, which are intended to control the risk of component failure due to undetected cracks or defects.
- All hardware in this mission class is classified for Fracture Control – Exempt, Non-fracture Critical, or Fracture Critical
- Fracture Critical: A classification that identifies a part where failure due to the presence of a crack is a catastrophic hazard ➔ Pressure vessels, engine components, primary structure, etc.
- Axiom 1: Material and manufacturing process produce structures and components with cracks or defects.
- Axiom 2: The presence of a crack or defect of sufficient size reduces the strength and life of the structure.
- Damage Tolerance: demonstration that a component can survive the service life (with a safety factor) in the presence of an undetected flaw or damage.
- Components are manufactured from aerospace quality materials using controlled processes.
- Components are inspected for damage (cracks, flaws, defects, etc.).
- Components are shown by test or analysis to be tolerant to undetected flaws.