Reusable spacecraft is increasingly attracting researchers’ attention. However, the experimental investigations on the turbine blade of the rocket engine are rarely published. Thus, the fatigue of a small impulse rocket turbine blade is explored in the current work. First, the specimen and the electrode of electrical discharge machining are carefully designed. Then, the electrical discharge machining is used to machine the specimen. To study the fatigue properties, the finite element analyses are separately performed on the blade model and the specimen. Based on the numerical results, a fatigue test is carried out to reproduce the most vulnerable position. Finally, the microstructural structures of the specimen are detected using the scanning electron microscope (SEM). Results show that (1) different from the aviation field, the specimen is unable to be machined with the welding method because it destroys the crucial details and the mechanical properties; (2) the maximum plastic strain is present at the leading edge close to the hub, at which a 760 μm corner crack appears at the 10113th fatigue cycle. This work provides a feasible method of using the EDM process to machine specimen for the small impulse turbine blade.

中文翻译：

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基于数值模拟和实验测试的小脉冲涡轮叶片疲劳研究

可重复使用的航天器越来越吸引研究人员的注意。但是，关于火箭发动机涡轮叶片的实验研究很少发表。因此，在当前工作中探索了小脉冲火箭涡轮叶片的疲劳。首先，仔细设计放电加工的样品和电极。然后，使用放电加工对样品进行加工。为了研究疲劳特性，分别对叶片模型和试样进行了有限元分析。根据数值结果，进行疲劳测试以重现最脆弱的位置。最后，使用扫描电子显微镜（SEM）检测样品的微观结构。结果表明（1）与航空领域不同，样品不能用焊接方法加工，因为它破坏了关键的细节和机械性能；（2）最大塑性应变出现在靠近轮毂的前缘处，在该处出现760 μ米角裂纹出现在10113th疲劳周期。这项工作提供了一种使用EDM工艺为小型脉冲涡轮叶片加工试样的可行方法。