High-frequency, high-temperature fretting-fatigue experiments

Abstract

Fretting fatigue is a structural damage mechanism observed when two contacting bodies are subjected to an oscillatory loading. A critical location for fretting fatigue induced damage has been identified at the blade/disk and blade/damper interfaces of gas turbine engine turbomachinery and space propulsion components. The high-temperature, high-frequency loading environment associated with such turbomachinery components can accelerate the fretting fatigue damage at these contact interfaces. The severe stress peaks and stress gradients that develop at the edge-of-contact can drive crack nucleation and propagation. These contact stresses are sensitive to the geometry of the contacting bodies, the contact loads, materials, temperature, and contact surface tribology (friction). To diagnose the threat that small and relatively undetectable fretting cracks pose to damage tolerance and structural integrity of in-service components, the objective of this work is to develop a well-characterized experimental fretting rig capable of investigating fretting behavior of advanced aerospace alloys subjected to load and temperature conditions representative of such turbomachinery components.