This document analyzes the acceptable service life of the first stage bladed-disk of the F-35B aircraft lift fan. It determines that the component can withstand up to 1.4 million flight cycles for high-cycle fatigue with a safety factor of 1.5 and has an infinite low-cycle fatigue life. Based on material properties and potential anomaly sizes, it recommends inspecting the component every 3,401 flight cycles to check for cracks. The analysis provides a feasible design for the lift fan with an overall efficiency of 0.867.

1. Lifing Analysis for First Stage Bladed-Disk of F-35B Aircraft Lift Fan
PITIPORNVIVAT, Maytwin
Objectives:
Outcomes/Results:
Thermal Power MSc, Aerospace Propulsion Option
School of Engineering
Methodology:
Conclusions
September 2014
• Investigate the acceptable service life
cycles of the first stage bladed-disc Lift
Fan regarding HCF, LCF, and crack
propagation life applying safe-life lifing
• Determine the proper inspection
interval for the first stage bladed-disc by
applying damage tolerance lifing
• The component acquires infinite LCF
life and can withstand HCF of up to
1.4x106 flight cycles with S.F. of 1.5
• Based on material anomaly sizes, it is
best to have the component inspected for
cracks once in every 3,401 flight cycles
• Achieved a feasible Lift Fan design with the
overall efficiency of 0.867 delivering PR = 2.1
Supervisor: HASLAM A.
Key References
• AC33.14-1, “Damage Tolerance for High Energy Turbine Engine Rotors”,
Federal Aviation Administration (FAA), U.S. Department of Transportation.
Flight Cycles S.F.
HCF Life 20,000 or (1.4x106) 2.08 or (1.5)
LCF Life Infinite N/A
Fracture Life 4,535 1.5
Inspection
Interval
3,401 N/A
• Maximum stress in the bladed-disk of 230.26
MPa at TE of 25% blade span with acceptable
static stress S.F. of 3.62
Comparison of inspection intervals for two phases of crack
propagation with max./min. material anomaly size