Modal identification for superstructure using virtual impulse response. Issue 16 (December 2019)

• Record Type: Journal Article
• Authors: Qu, Chun-Xu; Yi, Ting-Hua; Li, Hong-Nan
• Other Names: Zhou Lu guest-editor.; Ni Yi-Qing guest-editor.
• Is Part Of: Advances in structural engineering. Volume 22:Issue 16(2019)
• Page Start: 3503
• Page End: 3511
• Publication Date: 2019-12
• Subjects: eigensystem realization algorithm -- frequency response function -- modal identification -- superstructure -- virtual impulse response; Structural engineering -- Periodicals; Construction, Technique de la; Structural engineering; Periodicals; 624.1
• DOI: 10.1177/1369433219862951
• Languages: English
• ISSNs: 1369-4332

Abstract

In civil engineering, structural modes are identified with the assumption of stationary white noise, which cannot be satisfied in practical engineering. This article proposes a new method, which contains the virtual impulse response and eigensystem realization algorithm. The formulation of virtual impulse response is derived from the inverse Fourier transform of the ratio of the cross-power to auto-power spectral density functions of the measurement responses, which is based on the concept of frequency response function. During the formulation derivation, a single point excitation is only considered. Frequency response function would not change with different excitations and responses, which means that the excitation cannot influence frequency response function. The impulse response is pointed out to only represent the behavior of superstructure. After obtaining impulse responses, eigensystem realization algorithm is then performed to identify the modes of superstructure. The proposed method is validated by a numerical example. The results show that virtual impulse response can have much better free decayed behavior than natural excitation technique and identify very precise modal parameters for superstructure.