Simultaneous Identification of Moving Vehicles and Bridge Damages Considering Road Rough Surface

A method for the simultaneous identification of moving vehicles and the damages of the supporting structure from measured responses is presented. A two-axle vehicle model with two degrees of freedom (DOF) is adopted. The extent of the damage and the vehicle parameters were chosen as the optimisation variables, which allow ill conditioning to be avoided and decrease the number of sensors required. The identification is performed by minimising the distance between the measured responses and the computed responses to given optimisation variables. The virtual distortion method (VDM) was used, such that the response of the damaged structure can be computed from comparison with the intact structure subjected to the same vehicle excitation and to the response-coupled virtual distortions. These are related to the optimisation variables by the system impulse response matrix and are expressed by a linear system, which allowed both types of optimisation variables to be treated in a unified way. The numerical cost is reduced by using a moving influence matrix. The adjoint variable method is used for fast sensitivity analysis. A three-span bridge numerical example is presented, where the identification was verified with 5% root mean square (RMS) measurement, and model, error whilst also considering the surface roughness of the road.

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Numerical Stability Analysis of a Forced Two-D.O.F. Oscillator With Bilinear Damping

Journal of Computational and Nonlinear Dynamics ◽

10.1115/1.2727487 ◽

2007 ◽

Vol 2 (3) ◽

pp. 211-217 ◽

Cited By ~ 1

Author(s):

Zsolt Szabó ◽

Attila Lukács

Keyword(s):

Degrees Of Freedom ◽

Governing Equations ◽

Vehicle Model ◽

Pseudorandom Sequences ◽

First Order ◽

The Road ◽

Damping Behavior ◽

Numerical Stability Analysis ◽

Road Excitation ◽

The Stability

The current paper investigates the nonlinear stationary oscillations of a quarter vehicle model with two degrees of freedom subjected to a vertical road excitation. The damping of the wheel suspension has a bilinear characteristic, so that the damping strength is larger during compression than during restitution of the damper. For the optimization of the damping behavior the peak-to-peak swings have to be as small as possible. The unevenness of the road was approximated by filtered white noise which was modelled numerically using pseudorandom sequences. The first order form of the governing equations was transformed to hyperspherical representation. The stability was determined according to the largest Liapunov exponents obtained from the numerical simulation. For a chosen parameter range stability charts were constructed both in the stochastic and harmonic case (for comparison).

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Capturing Riding Characteristics of Double-Deck Bridges under Multi-Lane Moving Vehicles

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.587-589.1569 ◽

2014 ◽

Vol 587-589 ◽

pp. 1569-1576

Author(s):

Xue Tong Si ◽

Ke Jian Chen ◽

Wen Hua Guo

Keyword(s):

Degrees Of Freedom ◽

Road Vehicles ◽

The Road ◽

Long Span ◽

Long Span Bridge ◽

Moving Vehicles ◽

Direct Integration Method ◽

Road Surface Roughness ◽

Mass Spring ◽

Iso 2631

This paper investigates the characteristics of riding comfort of double-deck bridges under multi-lane moving vehicles based on a framework for spatial dynamic analysis of double-deck bridges carrying both road vehicles and monorail trains taking into account road surface roughness and both vertical and lateral track irregularities. The bridge is modelled by finite elements with proper boundary conditions. And the road vehicle is modelled as a mass-spring-damper system with 7 degrees of freedom (DOFs) while that of the monorail train has 15 DOFs. Then holistic bridge-vehicle interaction system was assembled using a fully computerized approach and solved by direct integration method. The riding characteristics of an authentic long-span bridge carrying both road vehicles and monorail trains are investigated in details as per ISO 2631.

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Sensitivity analysis of sandwich beams and plates accounting for variable support conditions

Bulletin of the Polish Academy of Sciences Technical Sciences ◽

10.2478/bpasts-2013-0019 ◽

2013 ◽

Vol 61 (1) ◽

pp. 201-210 ◽

Cited By ~ 1

Author(s):

R. Studziński ◽

Z. Pozorski ◽

A. Garstecki

Keyword(s):

Sensitivity Analysis ◽

Adjoint Variable Method ◽

Adjoint Variable ◽

Practical Applications ◽

The Core ◽

State Of Stress ◽

Thin Steel ◽

Influence Of Temperature On ◽

Support Conditions ◽

Variable Support

Abstract The paper addresses the problems of the sensitivity analysis and optimal design of multi-span sandwich panels with a soft core and flat thin steel facings. The response functional is formulated in a general form allowing wide practical applications. Sensitivity gradients of this functional with respect to dimensional, material and support parameters are derived using adjoint variable method. These operators account for the jump of the slope of a Timoshenko beam or a Reissner plate at the position of concentrated active load or reaction, thus extending the sensitivity operators known in literature. The jump of slope is the effect of shear deformation of the core. Special attention is focussed on sensitivity and optimisation allowing for variable support position and stiffness, because local phenomena observed in supporting area of sandwich plates often initiate failure mechanisms. Introducing optimally located elastic supports allows to reduce the unfavourable influence of temperature on the state of stress. Several examples illustrate the application of derived sensitivity operators and demonstrate their exactness

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FPGA and ASIC implementation of the algorithm for traffic monitoring in urban areas

Bulletin of the Polish Academy of Sciences Technical Sciences ◽

10.2478/v10175-011-0017-y ◽

2011 ◽

Vol 59 (2) ◽

pp. 137-140 ◽

Cited By ~ 2

Author(s):

S. Szczepański ◽

M. Wöjcikowski ◽

B. Pankiewicz ◽

M. KŁosowski ◽

R. Żaglewski

Keyword(s):

Urban Areas ◽

Traffic Monitoring ◽

Detection Algorithm ◽

Frame Rate ◽

Integrated Sensor ◽

The Road ◽

Moving Vehicles ◽

Direction Of Movement ◽

Account Due ◽

Selection Of

FPGA and ASIC implementation of the algorithm for traffic monitoring in urban areas This paper describes the idea and the implementation of the image detection algorithm, that can be used in integrated sensor networks for environment and traffic monitoring in urban areas. The algorithm is dedicated to the extraction of moving vehicles from real-time camera images for the evaluation of traffic parameters, such as the number of vehicles, their direction of movement and their approximate speed. The authors, apart from the careful selection of particular steps of the algorithm towards hardware implementation, also proposed novel improvements, resulting in increasing the robustness and the efficiency. A single, stationary, monochrome camera is used, simple shadow and highlight elimination is performed. The occlusions are not taken into account, due to placing the camera at a location high above the road. The algorithm is designed and implemented in pipelined hardware, therefore high frame-rate efficiency has been achieved. The algorithm has been implemented and tested in FPGA and ASIC.

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