0
TECHNICAL PAPERS

An Optimal Sensitivity-Enhancing Feedback Control Approach via Eigenstructure Assignment for Structural Damage Identification

[+] Author and Article Information
L. J. Jiang

Department of Mechanical & Nuclear Engineering, The Pennsylvania State University, University Park, PA 16802jiang@psu.edu

J. Tang

Department of Mechanical Engineering, University of Connecticut, Storrs, CT 06269jtang@engr.uconn.edu

K. W. Wang

Department of Mechanical & Nuclear Engineering, The Pennsylvania State University, University Park, PA 16802kwwang@psu.edu

J. Vib. Acoust 129(6), 771-783 (Feb 14, 2007) (13 pages) doi:10.1115/1.2748476 History: Received September 10, 2006; Revised February 14, 2007

The concept of using sensitivity-enhancing feedback control to improve the performance of frequency-shift-based structural damage identification has been recently explored. In previous studies, however, the feedback controller is designed to alter only the closed-loop eigenvalues, and the effect of closed-loop eigenvectors on the sensitivity enhancement performance has not been considered. In this research, it is shown that the sensitivity of the natural frequency shift to the damage in a multi-degree-of-freedom structure can be significantly influenced by the placement of both the eigenvalues and the eigenvectors. A constrained optimization problem is formulated to find the optimal assignment of both the closed-loop eigenvalues and eigenvectors, and then an optimal sensitivity-enhancing control is designed to achieve the desired closed-loop eigenstructure. Another advantage of this scheme is that the dataset of frequency measurement for damage identification can be enlarged by utilizing a series of closed-loop controls, which can be realized by activating different combinations of actuators in the system. Therefore, by using this proposed idea of multiple sensitivity-enhancing feedback controls, we can simultaneously address the two major limitations of frequency-shift-based damage identification: the low sensitivity of frequency shift to damage effects and the deficiency of frequency measurement data. A series of case studies are performed. It is demonstrated that the sensitivity of natural frequency shift to stiffness reduction can be significantly enhanced by using the designed sensitivity-enhancing feedback control, where the optimal placement of closed-loop eigenvectors plays a very important role. It is further verified that such sensitivity enhancement can directly benefit the damage identification accuracy and robustness.

FIGURES IN THIS ARTICLE
<>
Copyright © 2007 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

Schematic of the system model

Grahic Jump Location
Figure 2

Comparison of the left and right eigenvectors of the open-loop and closed-loop systems: (a1–a3) comparison of the first, second and third left eigenvectors, respectively, and (b1–b3) comparison of the first, second and third right eigenvectors, respectively

Grahic Jump Location
Figure 3

Comparison of the damage-induced natural frequency shifts of the open-loop and closed-loop systems: (a) comparison of the first natural frequency shift, (b) comparison of the second natural frequency shift, and (c) comparison of the third natural frequency shift

Grahic Jump Location
Figure 4

Comparison of the damage-induced natural frequency shifts of the optimal closed-loop system and the ad hoc closed-loop systems, (a) comparison of the first natural frequency shift, (b) comparison of the second natural frequency shift, and (c) comparison of the third natural frequency shift

Grahic Jump Location
Figure 5

Damage identification results using noise-contaminated natural frequencies of the open-loop system, ad hoc closed-loop systems and optimal closed-loop systems, respectively. The noise level is v=0.5%. Black bars: actual stiffness reduction; striped bars: prediction using noise-contaminated natural frequencies of the open-loop system; gray bars: prediction using noise-contaminated natural frequencies of the ad hoc closed-loop systems; checkered bars: prediction using noise-contaminated natural frequencies of the optimal closed-loop systems.

Grahic Jump Location
Figure 6

Damage identification results using noise-contaminated natural frequencies of the open-loop system, ad hoc closed-loop systems and optimal closed-loop systems, respectively. The noise level is v=2.0%. Black bars: actual stiffness reduction; Striped bars: prediction using noise-contaminated natural frequencies of the open-loop system; gray bars: prediction using noise-contaminated natural frequencies of the ad hoc closed-loop systems; checkered bars: prediction using noise-contaminated natural frequencies of the optimal closed-loop systems.

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In