压气机叶片复合疲劳试验系统的设计及疲劳寿命分析

为了模拟航空发动机工作典型状况,研究高低周复合疲劳对某型一级压气机叶片疲劳性能的影响,设计了高低周复合疲劳试验系统,进行了复合疲劳试验,振动试验及仿真分析；确定了叶片一阶振动频率为1530Hz,得出复合疲劳试验较纯低周加载缩短叶片寿命的作用高达586%。通过分析中值S N曲线和P S N曲线, S N曲线拟合系数高达099。通过对复合疲劳试验后的叶片断口进行分析,叶片断口的宏观和微观性状均出现了明显的疲劳源、高周扩展区、低周扩展区以及瞬断区,找到了叶片的断裂经历了高低周复合疲劳作用形成的明显特征区,最后说明了复合疲劳试验系统设计的合理性和可行性。 

Design of compound fatigue test system of compressor blade and fatigue life analysis

In order to simulate the typical working condition of aircraft engine, the effects of the high and low cycle compound fatigue on the fatigue performance of a certain level compressor blade were researched.To achieve the purpose, a high and low cycle combined fatigue test system was designed, and the compound fatigue test, vibration test and simulation analysis were conducted. It was concluded that the first order vibration frequency of the blade of 1530Hz was confirmed, and the compound fatigue test can significantly reduce blade life to 58.6% than pure low cycle loading; through analysis of the curves of S-N and P-S-N , the degree of fitting of S N curve can reach to 099. The fracture of the blades and the macroscopic and microscopic characteristics of the fracture showed fatigue source, high cycle loading extended area,low cycle loading extended area and fracture area at the same time. The clear characteristics area of fracture under the compound fatigue effect was found. The rationality and feasibility of this test system were illustrated.