关键词: 视情维修, 压气机叶片, 可用限制值, 单元体大修周期, 裂纹扩展

Abstract: During the service of aircraft engine compressor blades, cracks and other damages are prone to occur. Under the condition-based maintenance mode, maintenance decisions need to be made based on the available limit values specified in the maintenance manual. However, currently, there is a lack of systematic methods for determining the available limit values for crack-type damages in the maintenance manual under the condition-based maintenance mode. This paper takes the second-stage blades of the high-pressure compressor of a certain type of engine as the research object and proposes a method for determining the available limit values of cracks based on the blade failure criteria. A three-dimensional scan is used to establish the geometric model of the blade, and ABAQUS and FRANC3D are combined for finite element analysis and crack propagation simulation to obtain the crack propagation life curve. On this basis, by integrating the fracture toughness, inherent frequency deviation, and tip radial displacement failure criteria, a method for determining the available limit values for the external field and workshop of the blades is established, and the limit values are determined in combination with the engine maintenance interval. The results show that the external field available limit value for crack damage in the central area of the blade body of the HPC is 8 mm, and the workshop available limit value is 0.76 mm. Combined with the data from the external field and workshop maintenance manuals of this type of engine, the rationality of the available limit values, as well as the feasibility and effectiveness of the available limit value determination method, are verified, providing a method for determining the available limit values for crack-type damages of key components under the condition-based maintenance mode.

Key words: Condition-based maintenance, compressor blades, operational limit values, module overhaul intervals, crack propagation