Pagnotta Engineering

Fracture analysis calculates the life of a part when subject to cyclic loading. Unlike fatigue analysis, fracture analysis
determines crack propagation to failure assuming that a defect or flaw (crack) exists in the component.
The results of a fracture analysis is used to determine if modifications to a component are required.
Fracture analysis is also used to specify areas of inspection on a component even if the component is acceptable.

Generic Upgrade for Pan-Tilt Unit

• Finite Element Model of the Pan-Tilt Unit (PTU) created and run for anticipated launch loads
• Components classified according to JSC25863A, Fracture Control Plan for JSC
• Flight Hardware, August, 1998
• Fracture analysis of all components performed using NASGRO software
• Fracture-critical parts identified and re-designed where needed
• Inspection zones identified for all safe-life components

Isometric view of PTU Inspection Regions for the PTU Yoke
Fracture Critical (Safe-Life)
LAE heat shield stress plot for thermal loading

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