凹槽、套装联轴器等结构往往是汽轮发电机组轴系疲劳损伤的薄弱环节，对其进行应力分析至关重要，经验公式无法满足要求。以某600 MW汽轮发电机组轴系为例通过有限元建模方法对汽轮发电机组轴系进行扭应力分析，进一步得到薄弱环节的应力寿命曲线，优化疲劳极限取值，实现低幅值次同步振荡工况下的疲劳评估。采用多段集中质量模型分析扭振固有特性，结合轴系扭振固有特性和应力寿命曲线，评估机组轴系在次同步振荡工况下的疲劳损伤。此方法可用于评估汽轮发电机组轴系疲劳损伤情况。

For the complex shafting structures with grooves or couplings,which are often the weaknesses in sustaining fatigue damage,the stress analysis is critical,and the traditional empirical formula does not meet the requirement.In this paper,the torsional stress analysis of the turbine generator shaft system was carried out by using the finite element modeling method and the fatigue stress life curves of the weaknesses were further obtained.The fatigue limit value was optimized to realize the accurate fatigue evaluation under low amplitude sub-synchronous oscillation condition.Multi-part centralized quality model was applied to analyze the torsional vibration characteristics.Combining the inherent torsional characteristics of the shafting and stress life curves,the fatigue damage of the unit shaft system under sub-synchronous oscillation was further evaluated.With the shaft structure of a 600 MW turbo generator unit as an example,the analysis process using finite element modeling and stress life curve and the fatigue damage estimation was presented.This method can be used to estimate the fatigue damage of turbine generator set.

TK268.+1