An Adaptive Chirp Mode Decomposition-Based Method for Modal Identification of Time-Varying Structures
Year: 2024
Type: article
Abstract: Due to the effect of environmental factors and ambient loads, the physical and modal characteristics of a structure tend to change over time. Therefore, the effective identification of time-varying modal parameters has become an essential topic. In this study, a time-varying modal identification method based on adaptive chirp mode decomposition (ACMD) technique was proposed. The ACMD technique is highly adaptable for estimation of instantaneous frequencies of a structure. However, an initial frequency value exert an important influence on the accuracy of ACMD. To solve the above issue, the Welch power spectrum is firstly developed to obtain a high-resolution time-frequency distribution from measured signals to locate the time-frequency ridge as initial frequencies. Guided by the initial frequencies, the measured signals with multiple modal components can be decomposed into single time-varying components accurately by ACMD. Simultaneously, instantaneous frequencies can be directly identified by ACMD without other time-frequency methods. Next, a sliding window principal component analysis (PCA) method is proposed to obtain time-varying mode shapes. Finally, vibration data under various operational scenarios were taken to validate the proposed method, and the results show that the time-varying modal parameters of practical structures can be effectively identified.
Source: Mathematics
DOI: 10.3390/math12193157
Authors: Xiao-Jun Yao, Yu-Chun Lv, Xiao-Mei Yang, Feng-Yang Wang, Yong-Xiang Zheng
Language: English
Subfield: Civil and Structural Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,955
OpenAlex ID: W4403280440