CAJ | 학술논문

针对叶片运行中产生的疲劳裂纹会改变航空发动机振动特性及其频率转向、振型转换问题，建立航空发动机叶片有限元模型，基于结构模态振动理论研究裂纹参数，包括裂纹长度、裂纹位置变化对叶片固有振动及受迫振动特性影响；讨论频率转向区附近频率、振型变化规律。结果表明，裂纹长度、位置变化会逐渐改变叶片频率及振型，出现复杂的频率转向、模态耦合及振型转换特性，导致叶片同阶振动模态在不同裂纹长度、位置时具有不同的模态振型。
침대협편운행중산생적피로렬문회개변항공발동궤진동특성급기빈솔전향、진형전환문제，건립항공발동궤협편유한원모형，기우결구모태진동이론연구렬문삼수，포괄렬문장도、렬문위치변화대협편고유진동급수박진동특성영향；토론빈솔전향구부근빈솔、진형변화규률。결과표명，렬문장도、위치변화회축점개변협편빈솔급진형，출현복잡적빈솔전향、모태우합급진형전환특성，도치협편동계진동모태재불동렬문장도、위치시구유불동적모태진형。
Fatigue cracks generated during operation would alter the aero-engine blade vibration characteristics, manifested as frequency veering and mode shape switching.Study on the frequency veering can lead us to a further understanding of the blade crack evolution process.After building the FEM of aero-blade,the influence of crack parameters (crack location and length)on blade natural vibration and forced vibration characteristics was studied based on structural modal vibration theory,focusing on the variation laws of vibration frequency and mode shapes in the vicinity of frequency veering area.The results show that crack location and length variation would affect the blade frequencies and mode shapes,and thus lead to complex frequency veering,mode coupling and mode shape switching characteristics, which explains why mode shapes alter with the variation of crack length and location in the same order of vibration mode.