某低压涡轮工作叶片高温低循环疲劳寿命预测

针对某航空发动机低压涡轮工作叶片建立了全尺寸有限元模型·根据台架试验及实际工作承载条件,综合考虑叶片工作时所承受的离心负荷与气流力,进行了弹塑性有限元分析;研究了箍带与叶身小孔的配合间隙对结构应力场分布的影响,发现叶片结构强度的薄弱之处为榫头第一喉部、叶身小孔及叶背一侧圆根处·以此为依据,对叶片进行了高温低循环疲劳寿命预测·计算结果表明:叶身小孔与箍带的最大配合间隙对结构静强度及寿命影响较大,寿命计算时应当考虑平均间隙量的影响;随着计算温度的提高,寿命计算结果大幅度下降·

Prediction of High-Temperature Low-Cycle Fatigue Life of Aeroengine's Turbine Blades at Low-Pressure Stage

Develops a full-size finite element model of turbine blades at low-pressure stage. According to the test-rig used and actual working load, an elasto-plastic finite element analysis was made using the software ANSYS with the loads due to centrifugal force and airflow pressure to operating blades taken into account. The effect of fit clearance between hoping strips and blades orifices on the stress distribution on blade was explored. It was found that the weak points of the static blade strength are the first throat section of blade tenon, the blade orifices and the side round root of blade back. Then, a high-temperature low-cycle fatigue life was predicted for the turbine blades. The results showed that the maximum fit clearance between hoping strips and blade orifices affects greatly the static strength and fatigue life of blades, and the mean fit clearance should be taken into consideration when calculating fatigue life. In addition, the calculated fatigue life of blades lowers greatly with the increasing temperature.