关键词: 振动衰减信号;信号分离;阻尼参数辨识;布谷鸟搜索算法;变分模态分解

Abstract: In view of the difficulties in the accurate separation of each mode and in the accurate identification of its modal damping parameter of multiple modal signals, a method of parameter optimized variational mode decomposition based on cuckoo search (CS) algorithm named CS-VMD method and methods of modal damping parameter identification named envelope integral method (EIM) were proposed. The multiple modal components were accurately separated from the multi-modal vibration attenuation signals in the time domain by using CS-VMD method. And modal frequency and damping ratio of each mode were identified through EIM, and their identified results were compared with the theoretical values (or testing values) and the results identified by half power bandwidth method (HPB). The modal decomposition and modal parameter identification of a displacement simulation signal and the frequency testing signal of a compressor guide vane demonstrated that CS-VMD method can realize the correct decomposition of multiple modal signals, and the modal frequency identification errors of EIM are both below 1.0%. For the displacement simulation signal, the maximum error of the identified modal damping ratio through EIM is smaller than 2.5%. And for the frequency testing signal of the compressor guide vane, the maximum difference of the identified modal damping ratio between EIM and HPB method is 9.098%, and the accuracy of the modal damping identification of EIM is higher than that of HPB method.

Key words: Vibration attenuation signal;Signal separation;Damping parameter identification;Cuckoo search algorithm;Variational mode decomposition