Investigation of Local Damage and Impulse Delivered to Turbine Blades by Normal and Oblique Projectile Impacts.

摘要

Jet engine fan blades can be damaged by bullet impacts, or damage can occur when debris from the runway is ingested by the engine. Often, the impact can cause the fan blade to break into fragments which are also ingested by the engine. The local damage and impulse characteristics delivered to simulated blades from .50-caliber projectile impacts are examined. A combined approach involving numerical calculations and experiments is used to investigate damage and momentum transfer mechanisms for normal and oblique projectile impacts on Titanium, Aluminum, Boron-Aluminum, and Graphite-Epoxy plates. The normal impact calculations compare well with the experimental results. The major uncertainty in axisymmetric impact problems is in determining realistic dynamic material properties, especially for composite materials. The oblique impact experiments and numerical calculations demonstrate the fundamental importance of projectile yaw and rotation in determining the projectile-target damage and momentum transfer characteristics. Blade material ductility, and compressive and tensile strengths are the most important material properties involved in fan blade damage and momentum transfer from hard projectile impacts. (Author)