Comparison of time domain techniques for the evaluation of the response and the stability in long span suspension bridges

2007 ◽  
Vol 85 (11-14) ◽  
pp. 1032-1048 ◽  
Author(s):  
Francesco Petrini ◽  
Fabio Giuliano ◽  
Franco Bontempi
Keyword(s):  
Time Domain ◽  
Suspension Bridges ◽  
Long Span ◽  
The Stability

Nonlinear Stability Analysis of Long-Span Suspension Bridge Cable Tower

2014 ◽  
Vol 1030-1032 ◽  
pp. 802-806
Author(s):  
Xu Luo ◽  
Xin Sha Fu ◽  
Li Xiong Gu ◽  
Lu Rong Cai
Keyword(s):  
Finite Element ◽  
Nonlinear Stability ◽  
Geometrical Nonlinearity ◽  
Suspension Bridge ◽  
Suspension Bridges ◽  
Design Calculation ◽  
Safety Control ◽  
Finite Element Software ◽  
Long Span ◽  
The Stability

The cable tower is the bearing component of long-span suspension bridges, and its structure is very high and bear large force, which determines the stability and is the key of safety control. As for the height of the main tower of a long-span suspension bridge up to 195.3 m, the finite element software ANSYS is used to establish a three-dimensional finite element model (FEM), and the effects of geometric nonlinearity and material nonlinearity on the stability of the main tower are analyzed. The calculation results show that geometrical nonlinearity and material defects have significant influence on the main tower stability, and the nonlinear stability should be considered under wind load in the design calculation.

Flutter Control of Long Span Suspension Bridges in Time Domain Using Optimized TMD

2021 ◽  
Vol 21 (2) ◽  
pp. 731-742
Author(s):  
Hamed Alizadeh ◽  
Seyed Hossein Hosseni Lavassani
Keyword(s):  
Time Domain ◽  
Suspension Bridges ◽  
Long Span

Post-Critical Behavior of Suspension Bridges Under Nonlinear Aerodynamic Loading

2015 ◽  
Vol 11 (1) ◽  
Author(s):  
Andrea Arena ◽  
Walter Lacarbonara ◽  
Pier Marzocca
Keyword(s):  
Reduction Process ◽  
Design Parameters ◽  
Suspension Bridges ◽  
Long Span ◽  
Fold Bifurcation ◽  
Speed Up ◽  
The Stability ◽  
Parametric Analyses ◽  
Bifurcation Behavior ◽  
Nonlinear Aerodynamic

The limit cycle oscillations (LCOs) exhibited by long-span suspension bridges in post-flutter condition are investigated. A parametric dynamic model of prestressed long-span suspension bridges is coupled with a nonlinear quasi-steady aerodynamic formulation to obtain the governing aeroelastic partial differential equations adopted herewith. By employing the Faedo–Galerkin method, the aeroelastic nonlinear equations are reduced to their state-space ordinary differential form. Convergence analysis for the reduction process is first carried out and time-domain simulations are performed to investigate LCOs while continuation tools are employed to path follow the post-critical LCOs. A supercritical Hopf bifurcation behavior, confirmed by a stable LCO, is found past the critical flutter condition. The analysis shows that the LCO amplitude increases with the wind speed up to a secondary critical speed where it terminates with a fold bifurcation. The stability of the LCOs within the range bracketed by the Hopf and fold bifurcations is evaluated by performing parametric analyses regarding the main design parameters that can be affected by uncertainties, primarily the structural damping and the initial wind angle of attack.

Control of Vibrations due to Moving Loads on Suspension Bridges

2006 ◽  
Vol 11 (3) ◽  
pp. 293-318 ◽  
Author(s):  
M. Zribi ◽  
N. B. Almutairi ◽  
M. Abdel-Rohman
Keyword(s):  
Bridge Deck ◽  
Suspension Bridge ◽  
Lyapunov Theory ◽  
Dynamic Responses ◽  
Suspension Bridges ◽  
Control Force ◽  
Moving Loads ◽  
Hydraulic Actuator ◽  
Long Span ◽  
Suspended Cables

The flexibility and low damping of the long span suspended cables in suspension bridges makes them prone to vibrations due to wind and moving loads which affect the dynamic responses of the suspended cables and the bridge deck. This paper investigates the control of vibrations of a suspension bridge due to a vertical load moving on the bridge deck with a constant speed. A vertical cable between the bridge deck and the suspended cables is used to install a hydraulic actuator able to generate an active control force on the bridge deck. Two control schemes are proposed to generate the control force needed to reduce the vertical vibrations in the suspended cables and in the bridge deck. The proposed controllers, whose design is based on Lyapunov theory, guarantee the asymptotic stability of the system. The MATLAB software is used to simulate the performance of the controlled system. The simulation results indicate that the proposed controllers work well. In addition, the performance of the system with the proposed controllers is compared to the performance of the system controlled with a velocity feedback controller.

Wind Buffeting in Time Domain Analysis of Long-Span Bridges using RM Bridge

2017 ◽  
Vol 109 (6) ◽  
pp. 3307-3317
Author(s):  
Afshin Hatami ◽  
Rakesh Pathak ◽  
Shri Bhide
Keyword(s):  
Time Domain ◽  
Time Domain Analysis ◽  
Domain Analysis ◽  
Long Span Bridges ◽  
Long Span

Stability of Milling Operations With Asymmetric Cutter Dynamics in Rotating Coordinates

2016 ◽  
Vol 138 (8) ◽  
Author(s):  
Alptunc Comak ◽  
Orkun Ozsahin ◽  
Yusuf Altintas
Keyword(s):  
Time Domain ◽  
Machine Tools ◽  
High Speed ◽  
End Mill ◽  
Spindle Shaft ◽  
Milling Operations ◽  
Stability Model ◽  
Principal Directions ◽  
The Stability ◽  
Rotating Coordinates

High-speed machine tools have parts with both stationary and rotating dynamics. While spindle housing, column, and table have stationary dynamics, rotating parts may have both symmetric (i.e., spindle shaft and tool holder) and asymmetric dynamics (i.e., two-fluted end mill) due to uneven geometry in two principal directions. This paper presents a stability model of dynamic milling operations with combined stationary and rotating dynamics. The stationary modes are superposed to two orthogonal directions in rotating frame by considering the time- and speed-dependent, periodic dynamic milling system. The stability of the system is solved in both frequency and semidiscrete time domain. It is shown that the stability pockets differ significantly when the rotating dynamics of the asymmetric tools are considered. The proposed stability model has been experimentally validated in high-speed milling of an aluminum alloy with a two-fluted, asymmetric helical end mill.

Vibration Serviceability of Long Span Cable Bridges using Long-term Monitoring Data

2019 ◽  
Author(s):  
Eui-seung Hwang ◽  
Sun-Kon Kim ◽  
Do-Young Kim ◽  
Ki-Jung Park
Keyword(s):  
Monitoring Data ◽  
Suspension Bridges ◽  
Span Length ◽  
Bridge Design ◽  
Long Span ◽  
Vibration Serviceability ◽  
Long Term Monitoring ◽  
Deflection Limit ◽  
Term Monitoring

<p>Along with building slender and longer span structures, vibration serviceability becomes more important considerations in bridge design and maintenance. In this study, vibration serviceability and deflection limit for long span cable bridges are investigated using long-term monitoring data such as accelerations and displacements of bridges. Exampled bridges are Yi Sun-Sin Grand Bridge (suspension bridge, main span length=1,545m) and 2<sup>nd</sup> Jindo Grand Bridge (cable stayed bridge, main span length=344m). Long-term data are analyzed and compared with various design codes, guidelines, and other research results. Probability of exceedance are calculated for each criterion. Regarding on deflection limits, Korean Bridge Design Code (Limit State Design) specifies L/400 and L/350 for cable stayed and suspension bridges, respectively. Saadeghvaziri suggested deflection limit based on natural frequency, acceleration limit of 0.5 m/s² and vehicle speed. Various human comfort criteria on vibration are also applied including ISO standards. The results of this study are expected to be useful reference for the design, the proper planning and deflection review of the long span cable bridges around the world. Further researches are required to find the optimum deflection or vibration criteria for long span bridge and their effects on bridge clearance and elevation.</p>

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