摘要
针对重型燃气轮机叶片疲劳寿命研究的需要,通过设计和搭建的全尺寸叶片疲劳试验装置,模拟离心载荷工况下的低周疲劳试验,开展离心载荷下叶片应力分布和疲劳寿命预测的研究。该全尺寸叶片疲劳试验装置能够模拟低周疲劳中的等效离心载荷工况,为叶片试验提供必要的条件和手段。同时,对叶片进行网格划分和有限元仿真计算后,得到叶片Von mises应力分布结果,发现叶身应力最大处位于中部偏下边缘薄壁侧。然后将有限元仿真及应力试验相结合,提出叶片疲劳试验的离心载荷等效方法。在此基础上完成叶片的动应力试验,获得应力时间历程数据,并且给出离心载荷应力谱。结果表明,叶身中部边缘的应力水平最高,动应力谱幅值与频数概率的分布服从6阶麦克劳林拟合函数,用等效离心载荷疲劳寿命进行叶片寿命预测的结果是偏安全的,该结论可作为优化设计和试验研究的参考依据。
In order to investigate the fatigue life of the heavy-duty gas turbine blade, the research of the stress distribution and fatigue life prediction under the centrifugal load has to be carried out. A full size blade fatigue experiment device is designed and established, and the experiment condition of the low cycle fatigue centrifugal load can be simulated in this device. So the experiment device can simulate the equivalent centrifugal load conditions of the low cycle fatigue and provid the necessary conditions for the blade experiment. Meanwhile, the Von mises stress distribution of the blade is investigated with the finite element method. The maximum stress area is located in the thin edge side of the blade body. Then according to the results of the finite element simulation compared with the stress testing, the equivalent method of the centrifugal load is given for the fatigue experiment of the full size gas turbine blade. Through this kind of equivalent method, the dynamic stress experiment is completed. So both the stress time courses and the stress spectrum of the centrifugal load are obtained. The results show that the highest level of stress is in the middle of the blade edge. And in the dynamic stress spectrum, the distribution of the amplitude value and frequency probability follows the 6 th Maclaurin＇s fitting function. The prediction result of the blade fatigue life under the equivalent centrifugal load tends to safety. These conclusions can be taken as the reference for the optimization design and the experiment study.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2017年第22期212-218,共7页
Journal of Mechanical Engineering
基金
国家重点基础研究发展计划资助项目(973计划
2013CB035704)
关键词
燃气轮机叶片
等效离心载荷
疲劳试验
动应力谱
拟合函数
gas turbine blade
equivalent centrifugal load
fatigue experiment
dynamic stress spectrum
fitting function
