scholarly journals Natural Frequency of Tension Cable Based on Moment Inertia to Span Ratio: Determination Using Analytical, Numerical and Experimental Study

2020 ◽  
Vol 11 (2) ◽  
Author(s):  
Guntur Nugroho ◽  
Keyword(s):  
String Theory ◽  
Analytical Formula ◽  
Suspension Bridge ◽  
Bending Stiffness ◽  
Steel Beam ◽  
Cable Structure ◽  
Vibration Technique ◽  
Ratio Determination ◽  
Cylindrical Steel ◽  
Abaqus Software

Health monitoring using vibration technique is usually conducted on cable structure. The hanger cable on the suspension bridge has a difference of span. To predict axial force of cable, the beam-string theory includes a parameter of bending stiffness. However, string theory has neglected the effect of bending stiffness. The shorter the span of the cable the greater the effect of the bending stiffness would be. This paper raises parameter moment of inertia to span ratio (I/L) to determine the apropriate analytical formula between string and beam-string. Experimental research was conducted using a vibration technique. The specimens use solid cylindrical steel beam, having length specimens of 2 m, hinge-hinge of boundary condition, and difference variations I/L of 0.024, 0.08, 0.58, 1.53 and 10.22. Numerical analysis was simulated by using Abaqus software v 6.13. The result shows that the ratio of I/L equally lowers than 0.082 has close to the analytical string theory. The ratio of I/L greather than 0.082 has close to the beam string theory.

scholarly journals Parametric analysis of the dynamic characteristics of a long-span three-tower self-anchored suspension bridge with a composite girder

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Feifei Shao ◽  
Zhijun Chen ◽  
Hanbin Ge
Keyword(s):  
Finite Element ◽  
Dynamic Characteristics ◽  
Suspension Bridge ◽  
Bending Stiffness ◽  
Torsional Stiffness ◽  
Design Parameters ◽  
Long Span ◽  
Bending Mode ◽  
Main Cables ◽  
Central Buckle

Abstract Three-tower self-anchored suspension bridge (TSSB) is more and more favored because of its beautiful structure and strong adaptability to terrain and geological conditions. However, there are few engineering practices and related researches on super long-span three-tower self-anchored suspension bridges. A three-dimensional finite element model for the Fenghuang Yellow River Bridge, with the world’s longest span of its kind under construction, is established using the ANSYS finite element program, and the structural dynamic characteristics of the super long-span TSSB are studied and compared with those of several bridges of the same type or with similar spans. In addition, the influence of the key design parameters such as the stiffening girder stiffness, tower stiffness, main cable and suspender stiffness, central buckle, and longitudinal constraint system on the dynamic characteristics of the structure is analyzed. The results show that the first mode of the TSSB is longitudinal floating, the lower-order modes are dominated by vertical bending modes, while the higher-order modes are primarily vibration modes of the main cables, and the torsional modes exhibit strong coupling with the lateral sway of the towers and main cables. The frequency of the first antisymmetric vertical bending mode of the TSSB has an inversely proportional relationship with the main span length. Compared with a double-tower ground-anchored suspension bridge and cable-stayed bridge with similar spans, the TSSB has the lowest frequency for the first antisymmetric vertical bending mode and the highest frequency for the first symmetric vertical bending mode, with a more pronounced coupling with the towers and main cables in the torsional modes. Analysis of the structural parameters shows that the frequencies of the longitudinal floating mode, first antisymmetric vertical bending mode, first symmetric vertical bending mode, and first torsional mode are most sensitive to the longitudinal bending stiffness of the side tower, central buckle, vertical bending stiffness of the stiffening girder, and torsional stiffness of the stiffening girder, respectively. The research findings and relevant conclusions can provide basic data for response analysis of long-span TSSBs under dynamic loads and offer an engineering reference for the design of similar bridges around the world.

scholarly journals Performance validation and dynamic response analysis of a deepwater cable bending restrictor

2020 ◽  
Vol 37 (3) ◽  
pp. 95-101
Author(s):  
Kang Yongtian ◽  
Xiao Wensheng ◽  
Zhang Dagang ◽  
Zhang Liang ◽  
Zhou Chouyao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Numerical Analysis ◽  
Dynamic Response ◽  
Bending Stiffness ◽  
Offshore Wind ◽  
Response Analysis ◽  
Analysis Model ◽  
Element Analysis ◽  
Cable Structure ◽  
Pipe Model

The deepwater cable bending restrictor is an important protective device for risers, umbilicals and cables in offshore engineering, protecting cable structure by controlling minimum bending radius. Its mechanical properties are analysed based on the numerical analysis model and finite element analysis (FEM) of ø175. The sensitivity analysis of using quantity of bending restrictors is also performed to show the effect of the quantity on bending stiffness. A testing scheme of bending stiffness of the bending restrictor is then formulated based on its structure. From numerical analysis results through test simulation, the tolerance is less than 3 %, which verifies the reliability of the numerical analysis model. Performance of the bending restrictor and dynamic response are analysed according to environmental parameters that occur once per 100 years from offshore wind power farms and pipein-pipe models, respectively. The results show the bending restrictor can effectively protect cable structure, and the pipein-pipe model is suitable for calculating mechanical properties of interaction between the bending restrictor and cable.

Cable Deflection and Gravity Stiffness of Cable-Stayed Suspension Bridge

2011 ◽  
Vol 255-260 ◽  
pp. 1039-1042 ◽  
Author(s):  
Guo Ping Xia ◽  
Zhe Zhang
Keyword(s):  
Analytical Formula ◽  
Suspension Bridge ◽  
Energy Relation ◽  
Dead Load ◽  
The Dead ◽  
Different Parts ◽  
Load State

The paper studye the cable deflections of cable-stayed suspension bridge subject to living load. in addition, an analytical formula of the gravity stiffness of the cable-stayed suspension bridge is derived. Duo to the dead load state in the cable-stayed part is more differ from that in the suspension part, the research aim at different parts of the cable in the cable-stayed suspension bridge. Using the energy relation principle associated with deformation of the cable, the cable deflections and gravity stiffness of cable-stayed suspension bridge are derived.

Improved Dynamic Structural Modelling for Subsea Power Cables With Bitumen Coated Armour Wires

2017 ◽  
Author(s):  
Hugh Martindale ◽  
Steven Rossiter ◽  
Terence Sheldrake ◽  
Richard Langdon
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Dynamic Modelling ◽  
Bending Stiffness ◽  
Offshore Wind ◽  
Power Cables ◽  
Cable Structure ◽  
Non Linear ◽  
Low Tension

This paper presents improved dynamic modelling of subsea power cables using new models for the determination of non-linear cable mechanical properties. The modelling has been developed for cables typically used in offshore wind and for interconnectors, as well as dynamic power umbilicals. The results provide a better simulation of the dynamic response and allow better integration of local and global modelling for determination of stress and fatigue in offshore power cables. Cable response due to bending is modelled by including non-linear adhesion induced stresses due to a yielding bond between armour wire and neighbouring layers, which captures the effects of temperature and strain rate and provides better representation than purely friction-based modelling especially at low tension. Local armour bending stiffness is included by using average wire strain energy after slip along the strained helical path to determine the armour layer bending stiffness contribution. Mathematical modelling for mechanical properties is verified by sample testing and FEA, to provide a robust method for predicting cable response. Although dynamic subsea power cables are essentially non-bonded structures there is a certain amount of adhesion within the structure. Previous work has focused on friction-tension based modelling of armour wire-core interaction, that is not appropriate as critical slip curvatures at low tension are understated and full-slip stress distributions do not account for work done against friction during further bending. The principal result of this new approach is the improved determination of lifetime stresses for critical components within the cable structure. Non-linear bend stiffness modelling produces characteristic moment-curvature relations including hysteresis on reversal of bending. These curves provide an improved representation of the onset of slip in the armour wires and allow for the influence of temperature and strain rate on the cable bending stiffness to be included. The bend-stiffness model has been validated against test data both of complete bundles and individual components. The overall result is a methodology that typically results in increased fatigue life and can reduce the requirement for ancillary products such as ballast/buoyancy and bend stiffeners/restrictors. Additionally, the non-linear, hysteretic response of a cable significantly reduces certain phenomena that are often associated with numerical modelling of cables using a linear bend stiffness. Specifically, a cable catenary attached to a vessel and modelled with a linear bend stiffness will often experience ‘compression waves’ when the vessel is moving in response to wave loading. Use of a non-linear, hysteretic bend stiffness minimises the compression wave phenomenon, giving a much more realistic response and often greatly improving operability windows for offshore operations.

Behavior of through Beam Connections Composed of CFSST Columns and Steel Beams by Finite Element Studying

2010 ◽  
Vol 168-170 ◽  
pp. 2329-2333 ◽  
Author(s):  
Mohammad Mehdi Arabnejad Khanouki ◽  
Nor Hafizah Ramli Sulong ◽  
Mahdi Shariati
Keyword(s):  
Finite Element ◽  
Shear Failure ◽  
Nonlinear Finite Element ◽  
Steel Beams ◽  
Steel Beam ◽  
Finite Element Models ◽  
Shear Plate ◽  
Rigid Connection ◽  
Abaqus Software ◽  
Monotonic Load

Recent studies show that a through beam connections composed of concrete filled square steel tubular column and steel beam have been identified as an ideal rigid connection. In this paper a 3-D nonlinear finite element models were conducted for CFSST column and steel beam connection under monotonic load using ABAQUS software. Each model includes a CFSST column and single steel beam passing through the column. The main scopes are to identify the modes of beam failure and joint shear failure. In addition the effect of an extra shear plate welded to beam web inside the column was investigated. This result can be used for designing of through beam connection.

Effects Analysis of Bending Stiffness of Cables on Stress Distribution and Curve Shape in Super-Long Single Suspension Cable Structures

2010 ◽  
Vol 163-167 ◽  
pp. 173-176
Author(s):  
Tian Hu Jing ◽  
Qing Ning Li
Keyword(s):  
Stress Distribution ◽  
Cross Sections ◽  
Suspension Bridge ◽  
Bending Stiffness ◽  
Structural Safety ◽  
Curve Shape ◽  
Cable Structures ◽  
Long Span ◽  
Suspension Cable ◽  
Main Cables

The design scheme of a suspension bridge with a super-long-span of 3300 m was taken as an example, and calculating results from 3 mechanics models are compared with each other to study the effects of bending stiffness of cables on stress distribution and curve shape in super-long single suspension cable structures on the basis of the Finite Element Method (FEM) algorithm of ANSYS and the analytical segmental catenary method for cables’ shape-finding. The study shows that the influence of bending stiffness on curve shape-finding of cables is negligible; Although its effects on stress distribution in cross sections of main cables due to dead loads is small, the error of horizontal forces probably results in great one for the calculation of bending moments at the bottom cross-sections of bridge pylons, which needs attention to ensure the structural safety.

scholarly journals NUMERICAL ANALYSIS OF THE EFFECTS OF THE BENDING STIFFNESS OF THE CABLE AND THE MASS OF STRUCTURAL MEMBERS ON FREE VIBRATIONS OF SUSPENSION BRIDGES

2015 ◽  
Vol 21 (7) ◽  
pp. 948-957 ◽  
Author(s):  
Tatjana Grigorjeva
Keyword(s):  
Natural Frequencies ◽  
Mass Density ◽  
Suspension Bridge ◽  
Free Vibrations ◽  
Bending Stiffness ◽  
Suspension System ◽  
Mode Shapes ◽  
Suspension Bridges ◽  
Fe Method ◽  
Bridge Model

The article determines natural frequencies of vibration and the corresponding mode shapes of a suspension bridge with the varying bending stiffness of cables and examines variations that occur in these characteristics with respect to parametric changes in the bridge. A single span suspension steel footbridge with flexible cables has been selected as an initial model used for studying the dynamic characteristics of a suspension system. With the help of the finite elements (FE) method, parameter studies of the bridge model are presented in which vibration characteristics are studied as a function of structural and material parameters such as the flexural stiffness of the cable and the mass density of structural components. It has been generally found that the bending stiffness of the main cable contributes to a considerable effect on natural frequencies for this type of the suspension system. A simplified expression of predicting natural bending frequencies of the suspension bridge taking into account the bending stiffness of the cable has been developed for the application as the first step in the design process.

Study of the Bending Stiffness and Cable Characteristics of Tension Components

2012 ◽  
Vol 188 ◽  
pp. 17-24
Author(s):  
Mao Lin Tang ◽  
Ya Guang Du ◽  
Rui Li Shen ◽  
Kun Yan
Keyword(s):  
Computing Time ◽  
Characteristic Parameter ◽  
Bending Stiffness ◽  
Geometric Shape ◽  
Element Analysis ◽  
Hollow Beam ◽  
Cable Structure ◽  
Beam Elements ◽  
Calculation Results ◽  
Beam Characteristics

To study the behavior changing between cable characteristics and beam characteristics, the geometric shape calculation formulae for tension components with bending stiffness are derived from ones with the boundary conditions of two ends hinged, one hinged joint and the other fixed and two ends fixed respectively. Then, using the concept of tension stiffness, the effects of Cable Characteristic Parameter on the geometric shape of tension components are studied. Analyses indicate that with the increase in the value of the Cable Characteristic Parameter, the cable characteristics of components become more obvious. That is, a bar with enormous tension can be calculated as a cable element even if its bending stiffness is large. In structure finite element analysis, more storage space and computing time could be saved as long as components are simplified with cable elements other than beam elements, the simplification should be carried out basing on the Cable Characteristic Parameter. Calculation results on a hollow beam verify that when tension increases, components’ mechanical properties gradually change from beam characteristics to cable characteristics and eventually they tend to be identical with the theoretical calculation of cable structure.

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