Failure Analysis on a Counterweight Assembly of an Aeroengine

Abstract:

The paper presents a failure analysis on a counterweight assembly installed on crank shaft which resulted in an in-flight shutdown of a piston aeroengine. The counterweight assembly failure includes counterweight block material loss and fractured washer which is the most crucial part for in-flight shutdown in this type of aeroengine. Macro observation, fractography analysis, metallography analysis and hardness test were conducted on the failed counterweight assembly. The result shows that failure mechanism of counterweight block and washer is fatigue. The washer failure is likely due to inappropriate heat treatment process and continuous impact in flight by slightly tilted roller. Counterweight material loss is attributed to stress concentration, low structure strength and impact came from the tilted roller. Finally some safety suggestion on design and maintenance is given.

• Periodical: Advanced Materials Research (Volume 339)
• Pages: 342-348
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.339.342
• Online since: September 2011
• Authors: Hai Jun Tang, Hong Yu Yao
• Keywords: Counterweight Assembly Failure, Factography Analysis, Fatigue, In-Flight Shutdown

References

[1] HB 5492-1991. Microstructure examination of carburized and carbonitrided cases of aerospace steel. 1992, In Chinese.

[2] ISO 2639:2002. Steel-determination and verification of the effective depth of carburized and hardened cases. 2nd Edition, 2002.

[3] HB 5493-1991. Determination and verification of the effective depth of carburized and carbonitriding cases of aerospace steel. 1992, In Chinese.