Failure of life extended rotor discs of aeroengines

摘要

Over the past decade, aircraft readiness rates have declined, spare parts have been in short supply, and the cost of the turbine engine maintenance has escalated manifold. As a result, aircraft manufacturers and the operators throughout the world have embarked on an initiative to address sustainment of currently used turbine engines. The initiative is known as engine rotor life extension (ERLE) programme. Among the various fracture critical components of an aeroengine, rotor disc represents an immense asset, thus discarding them prior to expiration of full useful life causes a tremendous burden on the gas. turbine engine budget. Various approaches have been adopted to reassess the total useful life of a turbine rotor disc which mainly include (i) increasing the accuracy of the low-cycle fatigue life prediction methodology and (ii) increased confidence in the inspection process to locate smaller cracks and internal flaws. Combined with these, reworking of the discs has also been attempted. A couple of case histories on the failure of rotor discs are presented in this paper wherein reworking was carried out for extension of life. In both the cases, the failure resulted in accident. The critical aspects that are to be looked into to prevent failures in the extended life of-such reworked components are discussed.