Damage detection based on damping analysis of ambient vibration data

Abstract

Enabling an automated, remote and rapid detection of structural damage, sensor-based structural health monitoring is becoming a powerful tool for maintenance of civil engineering structures. In this study, a baseline-free, time-domain damage detection method was developed for concrete structures, which is based on analysis of nonlinear damping from measured structural vibration responses. The efficacy of the proposed method was demonstrated through a large-scale concrete bridge model subjected to different levels of seismic damage caused by shaking table tests. By applying the random decrement signature technique, the proposed method successfully identified, from its ambient vibration responses, nonlinear damping of the bridge associated with the seismic damage. The amount of the nonlinear damping increases as the seismic damage becomes more severe. This paper also compares the damage detection results with those obtained by stiffness-based methods, demonstrating a strong correlation between the increase in nonlinear damping and the decrease in structural stiffness associated with the increase in damage severity. valuable for post-seismic damage detection by improving the current visual inspection, which is time consuming, subjective, and potentially dangerous for inspectors.Research on vibration-based damage detection began in late 1970s in aerospace structures [1][2][3]. Then in the early 1980s, the research emerged to the civil engineering structures, especially for bridges and monumental structures. Many system identification techniques and damage detection methods have been developed over the past 30 years. Some full-scale tests were conducted, but researchers had difficulties to completely validate the efficacy of the proposed methods, mainly due to the unavailability of undamaged structures as a baseline. Of considerable interest was the research on large civil engineering structures developed since 1995 at the Los Alamos National Laboratory, as it allowed researchers to compare the dynamic response of a structure before and after the introduction of different levels of damage [4,5]. Most of these studies were based on changes in the dynamic characteristics of structures, since changes in physical properties cause detectable changes in modal parameters [6,7]. Usually these techniques are based on the measurement of changes in dynamic parameters including natural frequencies, mode shapes, and damping ratios. They are based on linear analysis, and their reliability and application range are widely known [8].The main issue that must be addressed, when the frequency-domain modal identification techniques are applied for seismic damage detection, is the presence of nonlinearity in the structural response. Most of the methods developed so far are based on frequency-domain analysis, which assumes linear structural responses. In case of civil engineering structures, this assumption is difficult to accept. As suggested by some studies [9,10], a nonlinear analysis is necessary during extreme events, because most civ...

Transfer function‐based Bayesian damage detection under seismic excitation

“…In recent studies, it is observed that the change in the damping of a structure was quite small compared with the stiffness degradation for typical buildings and bridge structures under small excitations . Hence, it can be assumed that the damping matrix is unchanged after the system is damaged when the system remains linearly elastic under small ground excitations .…”

“…In recent studies, it is observed that the change in the damping of a structure was quite small compared with the stiffness degradation for typical buildings and bridge structures under small excitations. [40,41] Hence, it can be assumed that the damping matrix is unchanged after the system is damaged when the system remains linearly elastic under small ground excitations. [31] In addition, due to the fact that the damping of a structure may not only relate to the material property of the elements, modeling and updating the damping may introduce significant inaccuracy into the model updating.…”

A frequency response function change method for damage localization and quantification in a shear building under ground excitation

“…Similarly, the cross-power spectra were calculated by multiplying the FFT of the output signals and the conjugate of the FFT of the input signals without taking an average. In addition to the FRFs of the system before and after the damage, system matrices, including the mass, damping, and stiffness matrices of the undamaged structure, are required to solve Equation (15). However, obtaining all the well-estimated or well-updated system matrices individually from an FE model is not an easy task.…”

Simultaneous identification of bridge structural parameters and vehicle loads

“…In summary, existing extensive vibration-based bridge system identification methods can be categorized as follows: (1) studies focusing on identification of bridge parameters based on dynamic measurements due to ambient excitations [16][17][18], earthquake excitations [19][20][21][22] or traffic-induced bridge responses with known traffic loads [23][24][25][26]; (2) the identification of dynamic vehicle axle loads or moving forces by assuming known bridge parameters; and (3) identification of both bridge and vehicle parameters with a full sensor placement or using measurements from both the bridge and vehicle subsystems.…”