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为获得航天器结构的更多故障信息,文章提出了一种应用经验模态分解对一个两层箱型结构进行裂纹故障诊断的方法。先对该结构进行有限元建模和模态分析,发现结构有无故障均对模态的影响非常小;再对实际结构进行正弦振动试验,对振动响应信号进行经验模态分解,利用固有模态函数构造标识向量,提取用标识向量间的标识夹角作为诊断结构故障的指标。分析结果表明,结合施加给结构的主振方向,利用标识夹角能识别出裂纹的位置和方向。该方法为航天器结构故障的诊断提供了一种新的思路。
In order to obtain more fault information of spacecraft structure, a method of applying empirical mode decomposition to crack fault diagnosis of a two-story box structure is proposed. Firstly, finite element modeling and modal analysis of the structure are carried out. The results show that the structure has little effect on the modal with or without fault. Then the sine vibration test of the actual structure is carried out to decompose the vibration response signal by empirical mode. The state function constructs the identification vector, and extracts the included angle between the identification vectors as an index to diagnose the structural failure. The analysis results show that the position and direction of the crack can be identified by the included angle of the mark in combination with the main vibration direction applied to the structure. The method provides a new idea for the diagnosis of spacecraft structural faults.