Coupled responses of stay cables under the combined rain–wind and support excitations by theoretical analyses

2020 ◽  
Vol 23 (11) ◽  
pp. 2261-2275
Author(s):  
Shouying Li ◽  
Yuanyuan Wang ◽  
Qingyu Zeng ◽  
Zhengqing Chen
Keyword(s):  
Equations Of Motion ◽  
High Order ◽  
Parametric Vibration ◽  
Stay Cable ◽  
Cable Tension ◽  
Coupled Equations ◽  
Stay Cables ◽  
Support Excitation ◽  
Source Excitation ◽  
Nonlinear Components

Stay cables on several cable-stayed bridges all over the world have been found to experience rain-wind-induced vibrations under the combined action of rain and wind. Meanwhile, the bridge deck might also have obvious oscillation under the wind and/or traffic loads. The coupled responses of a stay cable under the combined rain–wind and support excitations are numerically investigated in this article. The equations of motion of a three-dimensional continuous stay cable are derived by considering the high-order nonlinear components of the dynamic cable tension, together with the equation of motion of the rivulet on the cable surface. The forces induced by rain–wind excitation are determined by the quasi-steady theory, and the support excitation is achieved by the boundary condition. The coupled equations of the cable and the rivulet are numerically solved by using the finite difference method and the fourth-order Runge–Kutta method, respectively. The numerical results show that the high-order nonlinear components of the dynamic cable tension should be taken into account to numerically reproduce the parametric vibration of the stay cable, whereas they hardly have any effects on the rain-wind-induced vibration and the resonance vibration of the stay cable. The responses of stay cable under vertical support oscillation only and the rain–wind excitation only obtained from this study agree well with the literature results. Compared with the results induced by single-source excitation, the cable response amplitude under the combined excitations is smaller than that induced only by support excitation and larger than that induced only by rain–wind excitation. The rivulet is prone to be thrown from the cable surface if the parametric vibration of the stay cable is evoked.

scholarly journals Experimental Research on 2 : 1 Parametric Vibration of Stay Cable Model under Support Excitation

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Li-Na Zhang ◽  
Feng-Chen Li ◽  
Xiang Yu ◽  
Peng-Fei Cui ◽  
Xiao-Yong Wang
Keyword(s):  
Numerical Simulation ◽  
Experimental Research ◽  
Excitation Frequency ◽  
Parametric Vibration ◽  
Vibration Test ◽  
Test Model ◽  
Stay Cable ◽  
Test Analysis ◽  
Support Excitation ◽  
Bridge Bearing

For 2 : 1 parametric vibration problem of stay cable under support excitation, a sliding support only in the vertical moving is designed to simulate the bridge stay cable’s vibration test model. Meanwhile, using numerical simulation of cable free vibration and dynamic characteristic test analysis, the experimental research under various conditions is implemented in the actual cable-stayed bridge as the research object, which is compared with the corresponding numerical simulation results. According to the analysis results, it shows that as the vibration test model has 2 : 1 parametric vibration under the support excitation the results of maximum cable displacement from experimental analysis and numerical simulation are basically consistent which revealed that the parametric vibration of stay cable exists and is easy to occur. Additionally, when the bridge bearing excitation frequency is similar to the 2 : 1 frequency ratio, small excitation can indeed lead to the sharp “beat” vibration of cable; therefore it is very necessary to limit the amplitude of support excitation to prevent the occurrence of a large main parametric resonance.

Measuring Methods of Cable Tension in Cable-Stayed Bridges

2011 ◽  
Vol 295-297 ◽  
pp. 1230-1235
Author(s):  
Jiang Bo Sun ◽  
Zuo Zhou Zhao ◽  
Hong Hua Zhao
Keyword(s):  
Natural Vibration ◽  
String Model ◽  
Beam Model ◽  
Stay Cable ◽  
Fem Model ◽  
Cable Tension ◽  
Cable Stayed Bridge ◽  
Stay Cables ◽  
Beam Bending ◽  
Cable Stayed Bridges

This paper presents several methods usually used for measuring cable tension in cable-stayed bridges, especially frequency vibration method. Taken two different length stay-cables under given tension forces in a real cable-stayed bridge as an example, different modeling methods in finite element methods (FEM) were used to solve their natural vibration frequencies. The results by FEM were compared with those from other available theoretical predicting method. It was found that FEM based on tightening string model is more suitable for a long stay-cable. For a short stay-cable under given tension force, beam bending stiffness can be ignored in predicting its first five natural frequencies using a hinged beam model in FEM. While the predicted lower frequency using clamped beam FEM model is more accurate and reasonable.

scholarly journals Variational Mode Decomposition Based Time-Varying Force Identification of Stay Cables

2021 ◽  
Vol 11 (3) ◽  
pp. 1254
Author(s):  
Shitong Hou ◽  
Bin Dong ◽  
Jianhua Fan ◽  
Gang Wu ◽  
Haochen Wang ◽  
...  
Keyword(s):  
Good Effect ◽  
Time Varying ◽  
Variational Mode Decomposition ◽  
Stay Cable ◽  
Cable Tension ◽  
Force Identification ◽  
Stay Cables ◽  
Mode Decomposition ◽  
Cable Force ◽  
Cable Stayed Bridges

Stay cables are important structural members of cable-stayed bridges, which play a significant role in the health monitoring and assessment of cable-stayed bridges. The in-service cable force, which varies from the effects of vehicle load, wind load and other environmental factors, may cause fatigue damage in stay cables. Traditional force identification methods can only calculate the time-average cable force instead of the instantaneous force. A novel method has been proposed in this paper for identifying time-varying cable tension based on the variational mode decomposition (VMD) method. This recent method decomposes signals and adaptively estimates instantaneous frequency combined with the Hilbert–Huang transform method. In the proposed study, the time-varying modal frequencies were identified from stay cable acceleration data, and then the time-varying cable tension was identified by the relationship between cable tension and identified fundamental frequency. Scaled and full-scale models of stay cables were implemented successively to illustrate the validity of the proposed method. The results showed that the variational mode decomposition (VMD) method has a good effect on identifying the time-varying cable forces, even the sudden changes in cable force. According to the cable force identification results, the maximum error was 8.4%, which meets the actual application of time-varying cable force measurements. An on-site test was also implemented to monitor the cable force during a construction period, and the results showed that the proposed method can provide accurate real-time results for evaluation and decision-making.

The York-Arup cable experiments: Implications for the fire design of cable-supported bridges

2021 ◽  
Author(s):  
Benjamin Nicoletta ◽  
John Gales ◽  
Panagiotis Kotsovinos
Keyword(s):  
Thermal Strain ◽  
Experimental Studies ◽  
Thermal Response ◽  
Structural Response ◽  
Fire Performance ◽  
Stay Cable ◽  
Stay Cables ◽  
Bridge Structures ◽  
Recent Trends ◽  
High Level

<p>Recent trends towards performance-based fire designs for complex and critical structures have posed questions about the fire resilience of bridge infrastructure. There are little-to-no code requirements for bridge fire resistance and practitioner guidance on the subject is limited. Research on the fire performance of cable-supported bridge structures is scarce and knowledge gaps persist that inhibit more informed fire protection designs in a variety of bridge types. There have been few numerical or experimental studies that investigate the fire performance of steel stay-cables for use in cable-supported bridges. The thermal response of these members is critical as cable systems are highly dependent on the response of individual members, such as in the case of an anchor cable for example. The study herein examines the thermal response of several varieties of unloaded steel- stay cable during exposure to a non-standard methanol pool fire and the implications for the structural response of a cable-supported bridge. Experimental thermal strain data from fire tests of various stay-cables is used to inform high-level insights for the global response of a cable-supported bridge. Namely, the effects of cable thermal expansion on the overall cable system is approximated.</p>

Experimental Study of Fatigue Performance of Stay Cable Damper

2014 ◽  
Vol 487 ◽  
pp. 404-407
Author(s):  
Dong Liang ◽  
Zi Shuo Li
Keyword(s):  
Experimental Study ◽  
Good Condition ◽  
Experimental Results ◽  
Test Results ◽  
Stay Cable ◽  
Damping Force ◽  
Durability Test ◽  
Equivalent Damping ◽  
Stay Cables ◽  
Performance Deterioration

Oil dampers are widely used as a popular countermeasure to mitigate the stay cables vibration. In this study, one actual oil damper designed for some long cable-stayed was experimentally investigated to evaluate the durability. 4 million cycles loading, with frequency of 4 Hz and amplitude of 1 mm, was imposed on the damper. The excitation displacement and damping force were measured and the equivalent damping was calculated from the experimental results. The stiffness effects of dampers behaved during durability tests were also analyzed quantitatively. The test results showed that the dampers were still in good condition after 4 million cycles loading and the dampers temperatures were stable at 50 degree centigrade during the test. According to the durability test results, a model for performance deterioration of damper was proposed to predict the lifetime of oil dampers.

scholarly journals Stability of Soliton Solutions For A PT- Symmetric NLDC Considering High-Order Dispersion and Nonlinear Effects Simultaneously

2021 ◽  
Author(s):  
Lida Safaei ◽  
Mohsen Hatami ◽  
Mahmood Borhani Zarandi
Keyword(s):  
Communication Systems ◽  
Exact Analytical Solution ◽  
Nonlinear Effects ◽  
High Order ◽  
Order Effects ◽  
Coupled Equations ◽  
Solitary Solutions ◽  
Stability And Instability ◽  
The Stability ◽  
Order Dispersion

Abstract In this paper, we analytically solve the coupled equations of a PT -Symmetric NLDC by considering high-order dispersion and nonlinear effects (Raman Scattering and self-steeping) simultaneously in normal dispersion regime. To the best of knowledge no works has been done in previous studies to decoupled these equations and obtain an exact analytical solution. The new exact bright solitary solutions are derived. In addition, to study the stability and instability of these propagated solitons in a PT -Symmetric NLDC, perturbation theory is used. Numerical methods are applied to find perturbed eigenvalues and eigenfunctions. The Stability of obtained four perturbed eigenvalues and perturbed eigenfunctions for a PT -Symmetric NLDC equations regard to high-order effects are examined. Using these results and simulating the propagation of perturbed temporal bright solitons through PT -Symmetric NLDC show that perturbed solitons are mostly stable. This means that high-order dispersion and nonlinear effects canceled each other and do not affected the propagated solitons. Furthermore, the evolution of perturbed solitons energies match well the previous results and con rmed the stability of these solitons in a PT -Symmetric NLDC. As seen the energies of pulses in bar and cross behave in two manner 1) the exchange of energy is happened in some periods, but the shape of each pulse in bar and cross is preserved. Therefore, the solitons under this eigenfunction perturbation are mostly stable. 2) the evolution of energy in the bar and cross, demonstrate that there is no changes in their energies and they remain constant. It is straightforward to show that in spite of considering high-order effects, the perturbed soliton conserve the shape and it remain stable. The deliverables of this article not only demonstrate a novel approach to ultra-fast pulses, solitons and optical couplers, but more fundamentally, they could give insight for improving the new medical equipments technologies, enabling innovations in nonlinear optics and their usage in designing new communication systems and Photonic devices.

scholarly journals Serviceability Assessment Method of Stay Cables with Vibration Control Using First-Passage Probability

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Seunghoo Jeong ◽  
Young-Joo Lee ◽  
Sung-Han Sim
Keyword(s):  
Vibration Control ◽  
Control Method ◽  
Principal Component ◽  
Assessment Method ◽  
Stay Cable ◽  
First Passage ◽  
Long Span Bridges ◽  
Long Span ◽  
Stay Cables ◽  
Cable Stayed Bridges

As the construction of long-span bridges such as cable-stayed bridges increases worldwide, maintaining bridge serviceability and operability has become an important issue in civil engineering. The stay cable is a principal component of cable-stayed bridges and is generally lightly damped and intrinsically vulnerable to vibration. Excessive vibrations in stay cables can potentially cause long-term fatigue accumulation and serviceability issues. Previous studies have mainly focused on the mitigation of cable vibration within an acceptable operational level, while little attention has been paid to the quantitative assessment of serviceability enhancement provided by vibration control. This study accordingly proposed and evaluated a serviceability assessment method for stay cables equipped with vibration control. Cable serviceability failure was defined according to the range of acceptable cable responses provided in most bridge design codes. The cable serviceability failure probability was then determined by means of the first-passage problem using VanMarcke’s approximation. The proposed approach effectively allows the probability of serviceability failure to be calculated depending on the properties of any installed vibration control method. To demonstrate the proposed method, the stay cables of the Second Jindo Bridge in South Korea were evaluated and the analysis results accurately reflected cable behavior during a known wind event and show that the appropriate selection of vibration control method and properties can effectively reduce the probability of serviceability failure.

Inverse Identification of Non-Linear ODEs for the Dynamic Control of Material Testing Systems

2020 ◽  
Author(s):  
Evelyn M. Lunasin ◽  
Athanasios P. Iliopoulos ◽  
John G. Michopoulos ◽  
John C. Steuben
Keyword(s):  
Equations Of Motion ◽  
Dynamic Control ◽  
Material Testing ◽  
Naval Research ◽  
System Control ◽  
Numerical Verification ◽  
Inverse Identification ◽  
Coupled Equations ◽  
Actuation System ◽  
High Control

Abstract The development of advanced robotic systems for material testing by the U.S. Naval Research laboratory has expanded the set of requirements for mechatronic system control. This expansion lies beyond the limits of readily available control system capabilities because of the high control rate requirements. To establish this capability, a control mechanism based on the online identification of the ordinary differential equation governing the coupled equations of motion and deformation is proposed in the present work. The part of the proposed approach involving the inverse identification of the ODEs at hand is described in its general form first. Subsequently, the numerical verification is demonstrated via synthetic tests for a compliant actuation system with varying levels of noise injected in the system.

Axial Leakage Flow-Induced Vibration of Thin Cylindrical Shell With Respect to Circumferential Vibration

2002 ◽  
Author(s):  
Katsuhisa Fujita ◽  
Atsuhiko Shintani ◽  
Masakazu Ono
Keyword(s):  
Cylindrical Shell ◽  
Equations Of Motion ◽  
Fluid Pressure ◽  
Navier Stokes ◽  
Leakage Flow ◽  
Thin Cylindrical Shell ◽  
Flow Induced Vibration ◽  
Navier Stokes Equation ◽  
Coupled Equations ◽  
Unstable Vibration

In this paper, the dynamic stability of a thin cylindrical shell subjected to axial leakage flow is discussed. In this paper, the third part of a study of the axial leakage flow-induced vibration of a thin cylindrical shell, we focus on circumferential vibration, that is, the ovaling vibration of a shell. The coupled equations of motion between shell and liquid are obtained by using Donnell’s shell theory and the Navier-Stokes equation. The added mass, added damping and added stiffness in the coupled equations of motion are described by utilizing the unsteady fluid pressure acting on the shell. The relations between axial velocity and the unstable vibration phenomena are clarified concerning the circumferential vibration of a shell. Numerical parametric studies are done for various dimensions of a shell and an axial leakage flow.

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