Effect of the main cable bending stiffness on flexural and torsional vibrations of suspension bridges: Analytical approach

2021 ◽  
Vol 240 ◽  
pp. 112393
Author(s):  
Wen-ming Zhang ◽  
Xiao-fan Lu ◽  
Zhi-wei Wang ◽  
Zhao Liu
Keyword(s):  
Analytical Approach ◽  
Bending Stiffness ◽  
Suspension Bridges ◽  
Torsional Vibrations ◽  
Main Cable

Analysis and Test on Mechanical Properties of a Flexible Suspension Bridge

2013 ◽  
Vol 405-408 ◽  
pp. 1616-1622
Author(s):  
Guo Hui Cao ◽  
Jia Xing Hu ◽  
Kai Zhang ◽  
Min He
Keyword(s):  
Mechanical Properties ◽  
Suspension Bridge ◽  
Experimental Results ◽  
Suspension Bridges ◽  
Loading Test ◽  
Main Cable ◽  
Element Simulation ◽  
Static Loading Test ◽  
Geometric Nonlinear Analysis ◽  
Test Process

In order to research on mechanical properties of flexible suspension bridges, a geometric nonlinear analysis method was used to simulate on the experimental results, and carried on static loading test finally. In the loading test process, the deformations were measured in critical section of the suspension bridge, and displacement values of measured are compared with simulation values of the finite element simulation. Meanwhile the deformations of the main cable sag are observed under classification loading, the results show that the main cable sag increment is basically linear relationship with the increment of mid-span loading and tension from 3L/8 and 5L/8 to L/2 section, the main cable that increasing unit sag required mid-span loads and tension are gradually reduce in near L/4 and 3L/4 sections and gradually increase in near L/8 and 7L/8 sections and almost equal in near L/2, 3L/8 and 5L/8 sections. From the experimental results, the flexible suspension bridge possess good mechanical properties.

A Semi-Analytical Study of Stick-Slip Oscillations in Drilling Systems

2010 ◽  
Vol 6 (2) ◽  
Author(s):  
B. Besselink ◽  
N. van de Wouw ◽  
H. Nijmeijer
Keyword(s):  
Dynamic Analysis ◽  
Limit Cycle ◽  
Analytical Approach ◽  
String Model ◽  
Drill String ◽  
Axial Stiffness ◽  
Torsional Vibrations ◽  
Stick Slip ◽  
Rock Interaction ◽  
Stiffness And Damping

Rotary drilling systems are known to exhibit torsional stick-slip vibrations, which decrease drilling efficiency and accelerate the wear of drag bits. The mechanisms leading to these torsional vibrations are analyzed using a model that includes both axial and torsional drill string dynamics, which are coupled via a rate-independent bit-rock interaction law. Earlier work following this approach featured a model that lacked two essential aspects, namely, the axial flexibility of the drill string and dissipation due to friction along the bottom hole assembly. In the current paper, axial stiffness and damping are included, and a more realistic model is obtained. In the dynamic analysis of the drill string model, the separation in time scales between the fast axial dynamics and slow torsional dynamics is exploited. Therefore, the fast axial dynamics, which exhibits a stick-slip limit cycle, is analyzed individually. In the dynamic analysis of a drill string model without axial stiffness and damping, an analytical approach can be taken to obtain an approximation of this limit cycle. Due to the additional complexity of the model caused by the inclusion of axial stiffness and damping, this approach cannot be pursued in this work. Therefore, a semi-analytical approach is developed to calculate the exact axial limit cycle. In this approach, parametrized parts of the axial limit cycle are computed analytically. In order to connect these parts, numerical optimization is used to find the unknown parameters. This semi-analytical approach allows for a fast and accurate computation of the axial limit cycles, leading to insight in the phenomena leading to torsional vibrations. The effect of the (fast) axial limit cycle on the (relatively slow) torsional dynamics is driven by the bit-rock interaction and can thus be obtained by averaging the cutting and wearflat forces acting on the drill bit over one axial limit cycle. Using these results, it is shown that the cutting forces generate an apparent velocity-weakening effect in the torsional dynamics, whereas the wearflat forces yield a velocity-strengthening effect. For a realistic bit geometry, the velocity-weakening effect is dominant, leading to the onset of torsional vibrations.

Experimental Study on Mass Transfer Coefficient of Dry Air in Main Cable of Suspension Bridge

2012 ◽  
Vol 461 ◽  
pp. 151-154
Author(s):  
Dai Yong Jia ◽  
Lu Yan Sui ◽  
Ming Lai He
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Experimental Studies ◽  
Suspension Bridge ◽  
Suspension Bridges ◽  
Dry Air ◽  
Experiment Platform ◽  
Main Cable ◽  
Key Parameter

In this study, an experiment platform was built up to determine the key parameter, mass transfer coefficient, of the ventilation and dehumidification process in main cable of suspension bridge. On the basis of experimental studies, an empirical formula of the mass transfer coefficient was obtained, which can greatly contribute to control the content of moisture in the main cable of suspension bridges.

scholarly journals Circumferential Expansion Property of Composite Wrapping System for Main Cable Protection of Suspension Bridge

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Pengfei Cao ◽  
Hai Fang ◽  
Weiqing Liu ◽  
Yong Zhuang ◽  
Yuan Fang ◽  
...  
Keyword(s):  
Growth Rate ◽  
Bearing Capacity ◽  
Radial Displacement ◽  
Failure Modes ◽  
Suspension Bridge ◽  
Temperature Deformation ◽  
Suspension Bridges ◽  
Cross Sectional ◽  
Main Cable ◽  
Rubber Belt

A composite wrapping system for main cable protection of suspension bridges was designed by using prepreg fiber-reinforced composites and nitrile rubber. The circumferential expansion performance of the system was tested, and the curves of circumferential bearing capacity and radial displacement of the components were obtained. Failure modes of each group of components were compared and analyzed. The results show that most of the components are vertically fractured at the lap transition. The increase of the number of prepreg layers contributed the most to the circumferential bearing capacity of components, with a growth rate of 65.31%~109.01%. The increase of rubber belt layers had the most significant effect on the radial displacement of the components, with a growth rate of 7.06%~23.5%. In the initial stage of the test, the strain of each part of the component was smaller due to the compaction by the loading device, and the strain value of the component was generally linearly increased during the loading process, during which the strain of the overlap was the smallest. The calculated cross-sectional temperature deformation of the main cable is in good agreement with the experimental data. The application of the rubber belt increases the deformation of the main cable; therefore, the protection system for the main cable could have more deformation redundancy and delay the arrival of the ultimate strain of the outer prepreg wrap.

scholarly journals Simplified Analytical Method for Optimized Initial Shape Analysis of Self-Anchored Suspension Bridges and Its Verification

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Myung-Rag Jung ◽  
Dong-Ju Min ◽  
Moon-Young Kim
Keyword(s):  
Analytical Method ◽  
Bending Moment ◽  
Suspension Bridge ◽  
Suspension Bridges ◽  
Equilibrium Equations ◽  
Initial State ◽  
Initial Shape ◽  
Main Cable ◽  
Initial Shape Analysis ◽  
Bridge Models

A simplified analytical method providing accurate unstrained lengths of all structural elements is proposed to find the optimized initial state of self-anchored suspension bridges under dead loads. For this, equilibrium equations of the main girder and the main cable system are derived and solved by evaluating the self-weights of cable members using unstrained cable lengths and iteratively updating both the horizontal tension component and the vertical profile of the main cable. Furthermore, to demonstrate the validity of the simplified analytical method, the unstrained element length method (ULM) is applied to suspension bridge models based on the unstressed lengths of both cable and frame members calculated from the analytical method. Through numerical examples, it is demonstrated that the proposed analytical method can indeed provide an optimized initial solution by showing that both the simplified method and the nonlinear FE procedure lead to practically identical initial configurations with only localized small bending moment distributions.

Object-Oriented Computer-Aided Analysis for Construction Control of Anchored Suspension Bridge

2014 ◽  
Vol 543-547 ◽  
pp. 3977-3981
Author(s):  
Jian Yuan Sun ◽  
Cheng Zhang Yin ◽  
Zeng Bao Ma
Keyword(s):  
Safety Margin ◽  
Object Oriented ◽  
Suspension Bridge ◽  
High Accuracy ◽  
Object Oriented Programming ◽  
Suspension Bridges ◽  
Construction Control ◽  
Control Analysis ◽  
Finite Element Software ◽  
Main Cable

With the increase of the span of suspension bridge, the weight of the main cable increases, and the safety margin becomes smaller. Thus high accuracy is necessary for the construction control analysis of suspension bridges. The traditional finite element software cannot meet the accuracy requirement because of temperature, cable saddle and other factors, which influence the construction control. Based on the modified segmental catenary method, this paper has come up with a fine analysis method for the construction control of suspension bridges. And a software program called ZambisSC has been developed using object-oriented programming language combined with a number of the latest software development technologies. Compared with the monitoring results of Nancha suspension bridge in Guangzhou, China, it shows that ZambisSC can predict the main cable shape with high accuracy.

Bending Stiffness of a Double-Layered Graphene Sheet Using a Geometrically-Based Analytical Approach

2005 ◽  
Author(s):  
K. Behfar ◽  
R. Naghdabadi
Keyword(s):  
Potential Energy ◽  
Graphene Sheet ◽  
Material Property ◽  
Analytical Approach ◽  
Van Der Waals ◽  
Bending Stiffness ◽  
Van Der Waals Interactions ◽  
Atomic Spacing

In this article, the bending stiffness of a double-layered graphene sheet is investigated using a geometrically-based analytical approach. The analysis is based on the van der Waals interactions of atoms belonging to two neighboring sheets. The inter-atomic spacing between the adjacent layers is geometrically determined when the sheet is applied by a couple of moments in the opposite sides. The bending potential energy is obtained by summing up the potentials at discrete hexagons over the length and width of the sheet. It is observed that the bending stiffness of a double-layered graphene sheet does not depend on the length of the sheet and be a material property for the associated sheet.

Free Torsional Vibrations of Suspension Bridges

1979 ◽  
Vol 105 (4) ◽  
pp. 767-788
Author(s):  
Ahmed M. Abdel-Ghaffar
Keyword(s):  
Suspension Bridges ◽  
Torsional Vibrations
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