16. Abstract The objective of this research program is to investigate the potential for using system identification as a non-destructive evaluation technique. This research examines the feasibility of performing system identification on a large, multi-degree of freedom structure and a simple, single span structure. The testing consisted of performing sine sweeps over a range of excitation frequ...

Damage detection in civil engineering structures using changes in measured modal parameters is an area of research that has received notable attention in literature in recent years. In this paper two different experimental techniques for predicting damage location and severity have been considered: the Change in Mode Shapes Method and the Mode Shapes Curvature Method. The techniques have been a...

Recent developments in Artificial Neural Networks (ANNs) have opened up new possibilities in the domain of inverse problems. For inverse problems like structural identification of large structures (such as bridges) where in situ measured data are expected to be imprecise and often incomplete, ANNs may hold greater promise. This study presents a method for estimating the damage intensities of jo...

The vibration data obtained from ambient, drop-weight, and shaker excitation tests of the Z24 Bridge in Switzerland are analyzed to extract modal parameters such as natural frequencies, damping ratios, and mode shapes. System identification techniques including Frequency Domain Decomposition and Eigensystem Realization Algorithm are employed for the extraction of modal parameters and the statio...

The fundamental frequencies and mode shapes of steel and carbon fiber–reinforced plastic (CFRP) cylindrical shells with steel inserts were investigated using finite element analysis and modal testing. The free-free boundary condition was tested with modal testing using the roving hammer method and verified by finite element analysis using ABAQUS. The results show good agreement between the test...

An experimental investigation of an American five-string banjo is reported. The acoustic spectra of the strings are analyzed and it is found that in many ways banjo strings behave in a manner similar to those on a piano. The terminating impedance presented to the strings at the bridge is reported and it is found to be generally much lower than the characteristic impedance of the strings. It is ...

In this paper, effects of changing ambient temperatures on finite element (FE) model updating of the Dowling Hall Footbridge are investigated. The Dowling Hall Footbridge is located on the Tufts University campus in Medford, Massachusetts. The footbridge is equipped with a continuous monitoring system that records vibration and temperature of the bridge once an hour or when triggered by large v...

Bridge management officials have expressed a keen interest in the use of low-cost and easy-to-install wireless sensors to record bridge responses during short-term load testing. To illustrate the suitability of wireless sensors for short-term monitoring of highway bridges, a wireless monitoring system is installed upon the Grove Street Bridge to monitor structural responses during static and dy...

Image-based vibration mode identification gained increased attentions in civil and construction communities. A recent video-based motion magnification method was developed to measure and visualize small structure motions. This new approach presents a potential for low-cost vibration measurement and mode shape identification. Pilot studies using this approach on simple rigid body structures was ...

This article presents the results of experimental and theoretical studies of the v(O-H) and v(O-D) band shapes in the polarized infrared spectra of 3-thiophenic acid crystals measured at room temperature and at 77 K. The line shapes are studied theoretically within the framework of the anharmonic coupling theory, Davydov coupling, Fermi resonance, direct and indirect damping, as well as the sel...