Crack cause analysis of a third stage stator vane of the low-pressure compressor in an aeroengine

Abstract

A cracked third stage stator vane of the low-pressure compressor was found during a major overhaul of an aeroengine. The crack originated from a corrosion pit located on the arc transition between the leading edge and the upper edge plate. The finite element analysis results demonstrated the arc transition was the region with the large von-Mises stress under the wake excitation. The cleavage-like fracture and fatigue striations predominated throughout the fracture surface, indicating it was a pit-related fatigue crack. Meanwhile, Metallographic examination discovered most of corrosion pits beneath the bulging or peeling of the paint layer were distributed on the leading edge and the concave side. Moreover, the composition and phase identification results showed that the corrosion products included sulfate and alumina. Considering the pitting corrosion products and outdoor environment of the aircraft downtime, it was inferred that the cracked stator vane suffered from atmospheric corrosion.