Abstract Regularities of acoustic emission (AE) signals’ formation during cyclic loading of turbine blades of different Ni-based superalloys and steel specimens were considered and systematized. AE activity can be related to strain energy density, and for the beginning period of the cyclically loaded blade the value of summarized AE signals Nae recorded in a short time can be used for characterizing the critical state of blade material as blade durability Nf. The lower Nae for a considered time interval, the higher the blade durability Nf. Dependences of lgNf on lgNae were discovered in linear form with a high value of correlation factor. The similar relation between summarized AE signals and durability was demonstrated in the case of a monotonic blade bending with a stress level of 1% higher than in-service stress. For high accuracy of loading, a test-device that enables to load blades with a low velocity of stress level increasing was constructed. Well-known α-criterion appears when registered fatigue crack origination in a blade can be estimated in the number of cycles (Nf)α by the AE signals formation in a short time (Nae)t at the beginning stage of blade cyclic loading.

中文翻译：

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飞机结构寿命估计的声发射方法

摘要 研究并系统研究了不同镍基高温合金和钢试样涡轮叶片在循环加载过程中声发射(AE)信号的形成规律。AE活动可能与应变能密度有关，对于循环加载叶片的开始阶段，短时间内记录的汇总AE信号Nae的值可用于将叶片材料的临界状态表征为叶片耐久性Nf。在所考虑的时间间隔内，Nae 越低，叶片耐久性 Nf 就越高。lgNf 对 lgNae 的依赖性以具有高相关因子值的线性形式被发现。在应力水平比使用中应力高 1% 的单调叶片弯曲的情况下，证明了总结的 AE 信号与耐久性之间的类似关系。为了高精度的加载，构建了一种测试装置，能够以较低的应力水平增加速度加载叶片。当叶片中注册的疲劳裂纹起源可以通过在叶片循环加载的开始阶段在短时间内 (Nae)t 形成的 AE 信号以循环数 (Nf)α 进行估计时，就会出现众所周知的 α 准则。