American Society of Civil Engineers


Detection of Changes in Global Structural Stiffness Coefficients Using Acceleration Feedback


by Nebojsa Sebastijanovic, (Research Assistant, Dept. of Mechanical Engineering, Univ. of California, Santa Barbara, CA 93106.), Henry T. Y. Yang, (corresponding author), M.ASCE, (Professor, Dept. of Mechanical Engineering, Univ. of California, Santa Barbara, CA 93106 E-mail: henry.yang@chancellor.ucsb.edu), and Tian-Wei Ma, (Assistant Professor, Dept. of Civil and Environmental Engineering, Univ. of Hawaii at Manoa, Honolulu, HI 96822.)

Journal of Engineering Mechanics, Vol. 136, No. 9, September 2010, pp. 1187-1191, (doi:  http://dx.doi.org/10.1061/(ASCE)EM.1943-7889.0000159)

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Document type: Technical Note
Abstract: This technical note presents an extension of a previous study where two methods for detecting structural damage have been developed by using displacement and velocity measurements. In this study, acceleration feedback is used in detecting changes in global structural stiffness coefficients of lumped-mass-shear-beam models. The previously developed method relies on the decoupling of effects of changes in stiffness at different locations and the use of displacement or velocity feedback has proven to be effective. Extension to the use of acceleration feedback using existing formulation is not trivial in that the desired decoupling effect cannot be achieved by simple coordinate transformation because the acceleration itself is directly related to the stiffness coefficients. An approach to circumvent this difficulty is presented and it involves increasing the order of time derivatives of the linear system so that the acceleration becomes the "velocity" of the new system. The performance of the proposed method is demonstrated using an illustrative example of a three-story model with stiffness changes at different floors. Numerical studies are also conducted to evaluate the time horizons required to normalize monitor outputs for the effective and efficient detection of stiffness changes.


ASCE Subject Headings:
Damage
Assessment
Vibration
Feedback control
Structural reliability
Monitoring
Nondestructive tests
Seismic effects

Author Keywords:
Damage assessment
Vibration
Feedback control
Structural health monitoring
Nondestructive tests
Seismic effects