scholarly journals Experimental Verification for Cable Force Estimation Using Handheld Shooting of Smartphones

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Xuefeng Zhao ◽  
Kwang Ri ◽  
Niannian Wang
Keyword(s):  
Dynamic Characteristics ◽  
Natural Frequencies ◽  
Force Measurement ◽  
Moving Average ◽  
Rapid Development ◽  
Practical Significance ◽  
Force Estimation ◽  
Cable Stayed Bridge ◽  
Cable Force ◽  
Cable Force Estimation

Currently, due to the rapid development and popularization of smartphones, the usage of ubiquitous smartphones has attracted growing interest in the field of structural health monitoring (SHM). The portable and rapid cable force measurement for cable-supported structures, such as a cable-stayed bridge and a suspension bridge, has an important and practical significance in the evaluation of initial damage and the recovery of transportation networks. The extraction of dynamic characteristics (natural frequencies) of cable is considered as an essential issue in the cable force estimation. Therefore, in this study, a vision-based approach is proposed for identifying the natural frequencies of cable using handheld shooting of smartphone camera. The boundary of cable is selected as a target to be tracked in the region of interest (ROI) of video image sequence captured by smartphone camera, and the dynamic characteristics of cable are identified according to its dynamic displacement responses in frequency domain. The moving average is adopted to eliminate the noise associated with the shaking of smartphone camera during measurement. A laboratory scale cable model test and a pedestrian cable-stayed bridge test are carried out to evaluate the proposed approach. The results demonstrate the feasibility of using smartphone camera for cable force estimation.

Dynamic Characteristics of a Long-Span Cable-Stayed Bridge

2011 ◽  
Vol 480-481 ◽  
pp. 1496-1501
Author(s):  
Liu Hui
Keyword(s):  
Finite Element ◽  
Dynamic Characteristics ◽  
Iteration Method ◽  
Natural Frequencies ◽  
Element Model ◽  
Vibration Modes ◽  
Cable Stayed Bridge ◽  
Long Span ◽  
Subspace Iteration ◽  
Floating System

In order to study the dynamic characteristics of a super-long-span cable-stayed bridge which is semi-floating system, the spatial finite element model of this cable-stayed bridge was established in ANSYS based on the finite element theory.Modal solution was conducted using subspace iteration method, and natural frequencies and vibration modes were obtained.The dynamic characteristics of this super-long-span cable-stayed bridge were then analyzed.Results showed that the super-long-span cable-stayed bridge of semi-floating system has long basic cycle, low natural frequencies, dense modes and intercoupling vibration modes.

scholarly journals Cable force estimation of cables with small sag considering inclination angle effect

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Wen-Yu He ◽  
Fan-Cheng Meng ◽  
Wei-Xin Ren
Keyword(s):  
Boundary Conditions ◽  
Inclination Angle ◽  
Estimation Methods ◽  
Unknown Boundary ◽  
Force Estimation ◽  
Numerical Examples ◽  
Cable Force ◽  
Angle Effect ◽  
Unknown Boundary Conditions ◽  
Cable Force Estimation

AbstractCable force estimation is essential for security assessment of cable-stayed bridges. Cable force estimation methods based on the relationship between cable force and frequency have been extensively studied and used during both construction phase and service phase. However, the effect induced by inclination angle of the cable is not included in the establishment of frequency-cable force relationship as horizontal cable model is normally employed. This study aims to investigate the influence of the inclination angle on vibration based cable force estimation and provide practical formulas accordingly. Firstly numerical examples of fixed-fixed and hinged-hinged cables are simulated to illustrate the necessity of considering the inclination angle effect on the modal parameters and cable force estimation for inclined cables with small sag. Then practical formulas considering the inclination angle effect to estimate the cable force of fixed-fixed and hinged-hinged cables via the fundamental frequency are established accordingly. For the inclined cables with unknown boundary conditions, the coefficients reflecting boundary condition are predicted via the practical formulas for fixed-fixed and hinged-hinged cables. And the cable force considering the influence of inclination angle and unknown boundary conditions is obtained by iteration method. Finally, numerical examples are presented to demonstrate the effectiveness of the proposed method.

Noncontact cable force estimation with unmanned aerial vehicle and computer vision

2020 ◽  
Vol 36 (1) ◽  
pp. 73-88 ◽  
Author(s):  
Yongding Tian ◽  
Cheng Zhang ◽  
Shang Jiang ◽  
Jian Zhang ◽  
Wenhui Duan
Keyword(s):  
Computer Vision ◽  
Unmanned Aerial Vehicle ◽  
Force Estimation ◽  
Cable Force ◽  
Aerial Vehicle ◽  
Cable Force Estimation

Estimation and Optimization of Cable Force in Completion State of Cable-Stayed Bridge

2015 ◽  
Vol 744-746 ◽  
pp. 763-766
Author(s):  
Xun Wu ◽  
Bao Lei Li
Keyword(s):  
Internal Force ◽  
Continuous Beam ◽  
Force Estimation ◽  
Displacement Method ◽  
Cable Stayed Bridge ◽  
Completion Status ◽  
Analysis Calculation ◽  
Key Factor ◽  
Cable Force ◽  
Rigid Supports

The reasonable cable force is the key factor for the safe use of cable-stayed bridge. This paper adopts the method of continuous beam on rigid supports, zero displacement method and the internal force balanced method for cable force estimation of completion stage. The estimation value of cable force is determined by comprehensive considering various methods. With the estimate value as the initial cable force of feasible domain method, conducting the cable force optimization. Comparing the optimization with estimation value and conducting analysis calculation to ensure the rational completion status. Referring a cable-stayed bridge’s example, and conducting the estimation and optimization of cable force, the calculated results meet the requirements. The results show that the method is effective and practical.

scholarly journals Evaluation of Cable Force Changes Effects on Cable Stayed Bridge

2020 ◽  
Vol 6 (11) ◽  
pp. 2159-2174
Author(s):  
Theint Theint Thu Soe ◽  
San Yu Khaing
Keyword(s):  
Finite Element ◽  
Force Measurement ◽  
Research Work ◽  
Tension Stress ◽  
Percentage Increase ◽  
Stay Cable ◽  
The Real ◽  
Finite Element Software ◽  
Cable Stayed Bridge ◽  
Cable Force

The proposed bridge, which is cable stayed bridge crosses the Hlaing River that flows through Western Yangon. It was completed in 2000 and is currently used to connect Insein Township with Hlaing Tharyar Township. It has the 20 years’ service life. It requires the inspection and the evaluation of the real condition of the structure. As cable element plays an important role in cable structures, evaluation of the real state of the stay cable is one of the main focuses of the cable stayed bridge. Firstly, in the research work all cables are inspected to evaluate the current condition of the cables with included visual inspection and vibration-based cable force measurement method. With the help of static and moving load analysis, the effect of force change cables in which the successive force changes are considered, and the possible cable loss effect on the structural behavior of the bridge are also investigated. The finite element model of the cable stayed bridge is developed based on the geometric shape and material properties from MOC and is modelled with finite element software MIDAS Civil. The tension forces obtained by inspection over years (2000 to 2018) using vibration-based measurements method are compared with the measured intact cable forces. According to the results of the data analysis, it is observed that the cables force variations of the seven cables are abnormal conditions. In order to evaluate the condition of a bridge effected by cable force variation, the two parameters are considered; percentage increase in tension stress of all cables and percentage increase in deflection of the deck. The present study describes the structural response of the bridge in order to evaluate the actual safety of the bridge with abnormal force change cables, and also examines the consequences of one cable failure. Doi: 10.28991/cej-2020-03091609 Full Text: PDF

scholarly journals Model Order Identification for Cable Force Estimation Using a Markov Chain Monte Carlo-Based Bayesian Approach

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4187 ◽  
Author(s):  
Shaodong Zhan ◽  
Zhi Li ◽  
Jianmin Hu ◽  
Yiping Liang ◽  
Guanglie Zhang
Keyword(s):  
Monte Carlo ◽  
Markov Chain ◽  
Flexural Rigidity ◽  
Tensile Force ◽  
Suspension Bridge ◽  
Force Estimation ◽  
Model Order ◽  
Measured Frequency ◽  
Cable Force ◽  
Cable Force Estimation

The tensile force on the hanger cables of a suspension bridge is an important indicator of the structural health of the bridge. Tensile force estimation methods based on the measured frequency of the hanger cable have been widely used. These methods empirically pre-determinate the corresponding model order of the measured frequency. However, because of the uncertain flexural rigidity, this empirical order determination method not only plays a limited role in high-order frequencies, but also hinders the online cable force estimation. Therefore, we propose a new method to automatically identify the corresponding model order of the measured frequency, which is based on a Markov chain Monte Carlo (MCMC)-based Bayesian approach. It solves the limitation of empirical determination in the case of large flexural rigidity. The tensile force and the flexural rigidity of cables can be calculated simultaneously using the proposed method. The feasibility of the proposed method is validated via a numerical study involving a finite element model that considers the flexural rigidity and via field application to a suspension bridge.

scholarly journals Detection and localization of multiple small damages in beam

2021 ◽  
Vol 13 (1) ◽  
pp. 168781402098732
Author(s):  
Ayisha Nayyar ◽  
Ummul Baneen ◽  
Syed Abbas Zilqurnain Naqvi ◽  
Muhammad Ahsan
Keyword(s):  
Frequency Response ◽  
Natural Frequencies ◽  
Signal To Noise Ratio ◽  
Moving Average ◽  
A Priori ◽  
Damage Index ◽  
High Signal ◽  
Frequency Range ◽  
Spatial Locality ◽  
System Frequency

Localizing small damages often requires sensors be mounted in the proximity of damage to obtain high Signal-to-Noise Ratio in system frequency response to input excitation. The proximity requirement limits the applicability of existing schemes for low-severity damage detection as an estimate of damage location may not be known  a priori. In this work it is shown that spatial locality is not a fundamental impediment; multiple small damages can still be detected with high accuracy provided that the frequency range beyond the first five natural frequencies is utilized in the Frequency response functions (FRF) curvature method. The proposed method presented in this paper applies sensitivity analysis to systematically unearth frequency ranges capable of elevating damage index peak at correct damage locations. It is a baseline-free method that employs a smoothing polynomial to emulate reference curvatures for the undamaged structure. Numerical simulation of steel-beam shows that small multiple damages of severity as low as 5% can be reliably detected by including frequency range covering 5–10th natural frequencies. The efficacy of the scheme is also experimentally validated for the same beam. It is also found that a simple noise filtration scheme such as a Gaussian moving average filter can adequately remove false peaks from the damage index profile.

scholarly journals Modal Perturbation Method for the Dynamic Characteristics of Timoshenko Beams

2005 ◽  
Vol 12 (6) ◽  
pp. 425-434 ◽  
Author(s):  
Menglin Lou ◽  
Qiuhua Duan ◽  
Genda Chen
Keyword(s):  
Perturbation Method ◽  
Dynamic Characteristics ◽  
Timoshenko Beam ◽  
Natural Frequencies ◽  
Solution Process ◽  
Equation Of Motion ◽  
Timoshenko Beams ◽  
Algebraic Equations ◽  
Nonlinear Algebraic Equations ◽  
Shear Distortion

Timoshenko beams have been widely used in structural and mechanical systems. Under dynamic loading, the analytical solution of a Timoshenko beam is often difficult to obtain due to the complexity involved in the equation of motion. In this paper, a modal perturbation method is introduced to approximately determine the dynamic characteristics of a Timoshenko beam. In this approach, the differential equation of motion describing the dynamic behavior of the Timoshenko beam can be transformed into a set of nonlinear algebraic equations. Therefore, the solution process can be simplified significantly for the Timoshenko beam with arbitrary boundaries. Several examples are given to illustrate the application of the proposed method. Numerical results have shown that the modal perturbation method is effective in determining the modal characteristics of Timoshenko beams with high accuracy. The effects of shear distortion and moment of inertia on the natural frequencies of Timoshenko beams are discussed in detail.

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