Sparse and Low-rank Methods for Structural System Identification

Abstract: Sparse and low rank properties of structural dynamic response data can be exploited to develop sparse output-only structural system identification and damage detection techniques, as well the data compression and data cleansing techniques. First, the most popular blind source separation (BSS) technique, independent component analysis (ICA), which is able to extract sparse components, is combined with classic time-frequency representations (short-time-Fourier-transform (STFT) and wavelet transform (WT)) to develop new methods for modal identification and damage detection. Second, the system identification problem is solved using the complexity pursuit learning rule, which can identify a wide range of structures with highly-damped modes, closely-spaced modes, or complex modes even in the presence of non-stationary excitation. Third, the spirit of the sparsity property of modal responses, the sparse component analysis (SCA) modal identification method is presented; this algorithm handles the underdetermined problem (with an underlying sparse representation recovered by -minimization) where limited sensors may be available compared to the active modes of the structure. Fourth, the low rank/sparse methods for data denoising (cleansing) and image/video analysis are presented. Fifth, 2D-strain map realization algorithm from a limited number of strain measurements is presented. The seminar will conclude with a brief presentation of low-rank/sparse algorithm to dynamic video imaging data for damage detection in reinforced concrete beam.

Bio: Satish Nagarajaiah is a Professor of Civil and Environmental Engineering at Rice University, Houston. He obtained his Ph.D. from University at Buffalo, where he was a post-doctoral researcher before he started his academic career. His expertise is in nonlinear structural dynamics, advanced protective systems, adaptive stiffness systems, structural control, sparse structural system identification, and advanced sensing using nanomaterials. He has published extensively and presented several keynote lectures at international conferences. For full details visit his web site satishnagarajaiah.rice.edu. Dr. Nagarajaiah currently serves as the managing editor of the journal of structural engineering [ASCE], editor of the structural control and health monitoring international journal [Wiley] and editor-in-chief (North America) of the structural monitoring and maintenance international journal [Techno-press]. He is a fellow of ASCE and a fellow of Structural Engineering Institute (SEI) of ASCE. He was awarded the NSF CAREER award in 1998, ASCE Moisseiff Award in 2015 and ASCE Reese Research Award in 2017 for his research on Adaptive Stiffness Structures and sparse structural identification, respectively. Currently, he serves on the board of governors of ASCE SEI and on the Technical Activities Division Executive Committee. He has founded and chaired numerous committees in SEI, EMI, and IASCM on Structural Control and Monitoring.