气流激励下叶片的高周疲劳概率寿命预估

航空发动机中叶片振动引起的高循环疲劳失效是尤为突出的问题,将概率方法引入叶片高周疲劳寿命预估是叶片高周疲劳问题研究的重要途径。建立了叶片系统的概率疲劳积累损伤模型,由求得的振动应力出发,提出了一套完整的气流激励下叶片高周疲劳概率寿命的预估方法,分析中可以量化各种不确定因素对振动应力和疲劳寿命的影响,包括模态特征的不确定性和激励特征的不确定性。结合具体工程算例,分析得到某小型发动机二级静叶在工作转速下随工作时间增长的概率疲劳积累损伤,并给出了对应的工作可靠性。

Prediction on high cycle life of blades using probability method

High cycle fatigue(HCF) of blades caused by forced vibration is an problem for turbo engines.To solve HCF problems,it is effective to introduce probability method to obtain high cycle life of blades.The probability cumulative damage model according to blades was erected.Based on vibration stress,the numerical method to get probability cumulative damage and to obtain operational reliability was given.The randomicities were taken into account adequately including mode randomicity and load randomicity.Finally certain engineering sample was discussed to illustrate the method,and certain secondary stator used in a missile engine was given as an example.The probability cumulative damages altering with operation time were calculated,and the operational reliabilities were obtained according to each operation time.