Previous research based on theoretical simulations has shown the potential of the wavelet transform to detect damage in a beam by analysing the time-deflection response due to a constant moving load. However, its application to identify damage from the response of a bridge to a vehicle raises a number of questions. Firstly, it may be difficult to record the difference in the deflection signal between a healthy and a slightly damaged structure to the required level of accuracy and high scanning frequencies in the field. Secondly, the bridge is going to have a road profile and it will be loaded by a sprung vehicle and time-varying forces rather than a constant load. Therefore, an algorithm based on a plot of wavelet coefficients versus time to detect damage (a singularity in the plot) appears to be very sensitive to noise. This paper addresses these questions by: (a) using the acceleration signal, instead of the deflection signal, (b) employing a vehiclebridge finite element interaction model, and (c) developing a novel wavelet-based approach using wavelet energy content at each bridge section which proves to be more sensitive to damage than a wavelet coefficient line plot at a given scale as employed by others.

Publication informationVehicle System Dynamics, 46 (6) AbstractRoad roughness is a broad term that incorporates everything from potholes and cracks to the random deviations that exist in a profile. To build a roughness index, road irregularities need to be measured first. Existing methods of gauging the roughness are based either on visual inspections or using one of a limited number of instrumented vehicles that can take physical measurements of the road irregularities. This paper proposes the collection of data from accelerometers fixed in a specific vehicle type and the use of this data to estimate the road condition. While the estimate is approximate, accelerometers are being increasingly used by car manufacturers to improve suspension performance and the proposed method is relatively inexpensive to implement and provide road managers with constantly updated measurements of roughness. This approach is possible due to the relationship between the power spectral densities of road surface and vehicle accelerations via a transfer function. This paper shows how road profiles can be accurately classified using axle and body accelerations from a range of simulated vehicle-road dynamic scenarios. This is an electronic version of an article published in Vehicle System Dynamics, 46 (6): 483-499. Vehicle System Dynamics is available online at: http://www.informaworld.com/smpp/title~db=all~content=t713659010 2

Publication informationJournal of Sound and Vibration, 331 (18): 4115-4131Publisher Elsevier Item record/more information

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Magnetic nickel shells can be grown on gold nanorods with platinum tips by reduction of Ni2+ with hydrazine in aqueous cetyl‐trimethylammonium bromide (CTAB) solution, using Pt tips as catalysts. The plasmon absorption of the starting gold nanorods can be totally quenched by the metallic layer of nickel, while the magnetic character of these anisotropic, hybrid nanocrystals is demonstrated through alignment under an external magnetic field. Quasi‐epitaxial growth is demonstrated by HRTEM and electron diffraction (see figure).

Publication informationJournal of Sound and Vibration, 302 (3): 471-485 Publisher ElsevierLink to online version http://dx.doi.org/10.1016/j.jsv.2006.11.020Item record/more information http://hdl.handle.net/10197/2531Publisher's statement All rights reserved. Publisher's version (DOI)10. 1016/j.jsv.2006.11.020 Downloaded 2019-03-25T00:10:59ZThe UCD community has made this article openly available. Please share how this access benefits you. Your story matters! (@ucd_oa) Some rights reserved. For more information, please see the item record link above. AbstractThis paper presents a novel approach to the reduction of short-span bridge dynamic responses to heavy vehicle crossing events. The reductions are achieved through adjustment of the vehicle suspension damping coefficient just before the crossing.Given pre-calculations of the response of a vehicle-bridge system to a set of 'unit' road disturbances, it is shown that a single optimum damping coefficient may be determined for a given velocity and any specified road profile. This approach can facilitate implementation since the optimum damping is selected prior to the bridge and there is no need to continuously vary the damping coefficient during the crossing.The concept is numerically validated using a bridge-vehicle interaction model with several road profiles, both measured and artificially generated. The bridge-friendly damping control strategy is shown to reduce bridge dynamics across a typical range of vehicle velocities, proving most effective for road profiles that induce large vibrations in the vehicle-bridge system.

A new method is proposed in this paper for bridge damage detection using the response measured in a passing vehicle. It is shown theoretically that such a response includes three main components; vehicle frequency, bridge natural frequency and a vehicle speed pseudofrequency component. The Empirical Mode Decomposition (EMD) method is used to decompose the signal into its main components. A damage detection method is proposed using the Intrinsic Mode Functions (IMFs) corresponding to the vehicle speed component of the response measured on the passing vehicle. Numerical case studies using Finite Element modelling of Vehicle Bridge Interaction are used to show the performance of the proposed method. It is demonstrated that it can successfully localise the damage location in the absence of road profile. A difference in the acceleration signals of healthy and corresponding damaged structures is used to identify the damage location in the presence of a road profile. The performance of the method for changes in the transverse position of the vehicle on the bridge is also studied.

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