高DN值轴承损伤容限设计准则

Design criterions for high DN shaft-bearings using fracture mechanics

分析了航空发动机主轴承断裂的机理 ,指出在高速下轴承元件存在较大内应力 ,或轴承材料断裂韧性不足 ,有可能导致轴承元件在出现严重剥落前 ,材料内部的原始缺陷迅速扩展 ,超过临界裂纹尺寸而发生快速断裂。给出了两个高速轴承元件损伤容限设计准则 ;在实际中 ,应尽量提高轴承材料的高断裂韧性并采用先进探伤技术以加强对主轴承的监控及监测。

The fracture reasons of the main-shaft rolling bearings of the aircraft gas turbine are analyzed. The paper points out that the rolling bearings have higher inner stresses or the materials are lack of fracture flexibility in high speed, those may cause the initial defects of the material extend rapidly and exceed the critical crack dimension, which lead to the rolling bearings fracture before the elements emerge the severe spalling. Two design criterions of damage endurance for high speed rolling bearing are given. The fracture flexibility of the bearing material should be enhanced and advanced crack detection technology should be adopted to monitor and control the main-shaft rolling bearing in practice.