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Typical engineering cable structures, such as high-voltage wire and wire rope, usually bring a damping effect which cannot be ignored due to the technological problems of manufacturing. For such problems, especially the damping of cable structures undergoing large displacement and severe deformation, few studies have been reported in the past. In this work, the fractional derivative viscosity model is introduced into the cables described by the absolute nodal coordinate formulation. The computer implementation algorithm of the proposed cable damping model is given based on the three-parameter fractional derivative model. Two numerical examples demonstrate the effectiveness and convergence property of the proposed cable damping model. An experiment is proposed in which a wire is tensioned and released. Configurations are captured by the high-speed camera and compared with the results obtained from the numerical simulation. The agreement of the simulation and experimental results validates the proposed cable damping in application. [ABSTRACT FROM AUTHOR]

Typical engineering cable structures, such as high-voltage wire and wire rope, usually bring a damping effect which cannot be ignored due to the technological problems of manufacturing. For such problems, especially the damping of cable structures undergoing large displacement and severe deformation, few studies have been reported in the past. In this work, the fractional derivative viscosity model is introduced into the cables described by the absolute nodal coordinate formulation. The computer implementation algorithm of the proposed cable damping model is given based on the three-parameter fractional derivative model. Two numerical examples demonstrate the effectiveness and convergence property of the proposed cable damping model. An experiment is proposed in which a wire is tensioned and released. Configurations are captured by the high-speed camera and compared with the results obtained from the numerical simulation. The agreement of the simulation and experimental results validates the proposed cable damping in application.

[Display omitted] • A framework for 3D noncontact stereovision-based displacement measurement with phased-based video motion magnification (PVMM) is proposed for measurement of stay cable's micro vibration. • Pixel displacements of cables were extracted from recorded videos using Centroid-based Bounding-Box Tracking (CBBT) method. Cable 3D global displacements were determined using Particle Swarm Optimization (PSO). • Stay cable frequency and damping were estimated using wavelet-screening Random Decrement Technique (WS-RDT). • Validation of the proposed stay cable measurement framework in wind-tunnel tests. This paper proposes a new framework for 3D noncontact stereovision-based displacement measurement in conjunction with Phase-based Video Motion Magnification (PVMM) to capture in-plane and out-of-plane vibrations of stay cables. In the proposed method, cable vibrations are captured by a pair of synchronized digital cameras, then PVMM method is applied to magnify micro vibrations of the cable (ambient responses) recorded by video cameras. Next, a camera calibration technique is proposed to convert the 2D image coordinates to 3D global coordinates, followed by the stereo calibration between the two cameras to synchronize the target points. Afterwards, a Centroid-based Bounding-Box Tracking (CBBT) technique is proposed and used to track the movements of the cable in each video frame. As a result, time-history displacements of the cable are extracted from the magnified videos. Finally, natural frequencies and damping ratios of the cable are extracted from the in-plane and out-of-plane displacements using Wavelet-screening Random Decrement Technique (WS-RDT). The proposed methodology has been validated through a couple of wind-tunnel tests of cable vibrations. The results have demonstrated a good agreement between the proposed method and conventional accelerometer-based measurement results. [ABSTRACT FROM AUTHOR]

This paper deals with an experimental measurement campaign carried out with a modified dynamometric Stockbridge damper clamped to a laboratory test span. The aim is to get the force and the torque exerted between the cable and the damper on a span. This approach obtains the mechanical impedance of the damper under real working conditions, with the possibility to separate the contribution of the torque and of the force out of the global losses, and to compare these results with those obtained on a shaker where only the vertical motion is imposed, with no rotation. More than 100 experimental tests were executed from February 2001 to July 2001, also looking for a metrological validation of the results and for quality assessment of the collected data. Some results are shown, pointing out a comparison between the damper behavior on the span and on dynamic exciter. [ABSTRACT FROM PUBLISHER]