An online monitoring technology of tower foundation deformation of transmission lines

2018 ◽  
Vol 18 (3) ◽  
pp. 949-962 ◽  
Author(s):  
Xinbo Huang ◽  
Long Zhao ◽  
Ziliang Chen ◽  
Cheng Liu
Keyword(s):  
Transmission Lines ◽  
Online Monitoring ◽  
Element Model ◽  
Mining Area ◽  
Stress Tests ◽  
Monitoring Technology ◽  
Internal Relations ◽  
Foundation Deformation ◽  
Set Up ◽  
Tower Foundation

In this article, an online monitoring technology applied to transmission line towers is proposed to overcome the problems that the foundation deformation is difficult to find in the mining area, river, hillside, and other special areas. The measurement of the stress or the strain caused by the tower foundation deformation are rarely issued, though the tower status can be possibly assessed by the stress or the strain. A new online monitoring technology of tower foundation deformation of transmission lines is developed which consists of three parts. In the first part, the stress or the strain of the key elements is effectively analyzed under the different deformations such as foundation settlement, inclination, and side-slip with the tower finite element model built and the wind load and ice load applied on the tower. In the second part, the experimental platform of tower stress tests is set up, and the internal relations between the stress variation and the tower foundation deformation are determined. In the third part, the online monitoring technology of tower foundation deformation of transmission lines is developed based on fiber Bragg grating stress sensor and successfully applied in Jibei power grid in China. The results show that all the monitored stresses fluctuating with the wind speed are small in case that the condition of tower foundation is normal; on the contrary, the corresponding stresses will change greatly.

Simulation Study of Stability of the Transmission Tower Foundations on Mined-Out Area

2013 ◽  
Vol 438-439 ◽  
pp. 1116-1120
Author(s):  
Zhao Guang Li ◽  
Zhi Li Sui ◽  
Wen Li Li ◽  
Xin Shuo Sun ◽  
Tie Jun Xu
Keyword(s):  
Transmission Lines ◽  
Power Transmission ◽  
Mutual Influence ◽  
Mining Area ◽  
Economic Benefits ◽  
Transmission Tower ◽  
Mining Site ◽  
Electric Transmission Lines ◽  
Surface Iron ◽  
Tower Foundation

As more and more electric transmission lines have to go through the mining area, if we can fully realize the collapse and deformation characteristics of mined-out area, and master the scientific laws of its occurrence and development, we may take reasonable measures to avoid the happening of accidents, ensure the line to run in a reliable way, and greatly improve the construction quality and economic benefits. For different location conditions of coal mine worked out section to the surface of the power transmission tower, we use finite difference software FLAC3D to analyze mutual influence and interaction between underground worked out section and surface iron tower foundation. The conclusion in this paper can be used as a reference to mining site. The influence range can be estimated before mining, as far as possible avoiding influence within the scope of strata. It is the key to ensure the safety of power transmission tower, people life and property.

scholarly journals Vibration characteristics of triple-gear-rotor system in compressed air energy storage under variable torque load

2021 ◽  
Vol 104 (1) ◽  
pp. 003685042098705
Author(s):  
Xinran Wang ◽  
Yangli Zhu ◽  
Wen Li ◽  
Dongxu Hu ◽  
Xuehui Zhang ◽  
...  
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Element Model ◽  
Rotor System ◽  
Dynamic Responses ◽  
System Response ◽  
Rotating Speed ◽  
Torque Load ◽  
Set Up ◽  
Two Stages

This paper focuses on the effects of the off-design operation of CAES on the dynamic characteristics of the triple-gear-rotor system. A finite element model of the system is set up with unbalanced excitations, torque load excitations, and backlash which lead to variations of tooth contact status. An experiment is carried out to verify the accuracy of the mathematical model. The results show that when the system is subjected to large-scale torque load lifting at a high rotating speed, it has two stages of relatively strong periodicity when the torque load is light, and of chaotic when the torque load is heavy, with the transition between the two states being relatively quick and violent. The analysis of the three-dimensional acceleration spectrum and the meshing force shows that the variation in the meshing state and the fluctuation of the meshing force is the basic reasons for the variation in the system response with the torque load. In addition, the three rotors in the triple-gear-rotor system studied show a strong similarity in the meshing states and meshing force fluctuations, which result in the similarity in the dynamic responses of the three rotors.

scholarly journals Corrosion of Steel Rebars in Anoxic Environments. Part II: Pit Growth Rate and Mechanical Strength

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2547
Author(s):  
Elena Garcia ◽  
Julio Torres ◽  
Nuria Rebolledo ◽  
Raul Arrabal ◽  
Javier Sanchez
Keyword(s):  
Mechanical Strength ◽  
Chloride Content ◽  
Element Model ◽  
Offshore Structures ◽  
Anoxic Environments ◽  
Electrochemical Parameters ◽  
Cathode Area ◽  
Optical Profilometer ◽  
Set Up ◽  
Corrosion Of Steel

Reinforced concrete may corrode in anoxic environments such as offshore structures. Under such conditions the reinforcement fails to passivate completely, irrespective of chloride content, and the corrosion taking place locally induces the growth of discrete pits. This study characterised such pits and simulated their growth from experimentally determined electrochemical parameters. Pit morphology was assessed with an optical profilometer. A finite element model was developed to simulate pit growth based on electrochemical parameters for different cathode areas. The model was able to predict long-term pit growth by deformed geometry set up. Simulations showed that pit growth-related corrosion tends to maximise as cathode area declines, which lower the pitting factor. The mechanical strength developed by the passive and prestressed rebar throughout its service life was also estimated. Passive rebar strength may drop by nearly 20% over 100 years, whilst in the presence of cracking from the base of the pit steel strength may decline by over 40%.

scholarly journals Galloping Stability and Wind Tunnel Test of Iced Quad Bundled Conductors considering Wake Effect

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Xiaohui Liu ◽  
Ming Zou ◽  
Chuan Wu ◽  
Mengqi Cai ◽  
Guangyun Min ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Transmission Lines ◽  
Degrees Of Freedom ◽  
Wind Tunnel Test ◽  
Aerodynamic Coefficients ◽  
Wake Effect ◽  
Aerodynamic Coefficient ◽  
Set Up ◽  
The Stability ◽  
Three Degrees Of Freedom

A new quad bundle conductor galloping model considering wake effect is proposed to solve the problem of different aerodynamic coefficients of each subconductor of iced quad bundle conductor. Based on the quasistatic theory, a new 3-DOF (three degrees of freedom) galloping model of iced quad bundle conductors is established, which can accurately reflect the energy transfer and galloping of quad bundle conductor in three directions. After a series of formula derivations, the conductor stability judgment formula is obtained. In the wind tunnel test, according to the actual engineering situation, different variables are set up to accurately simulate the galloping of iced quad bundle conductor under the wind, and the aerodynamic coefficient is obtained. Finally, according to the stability judgment formula of this paper, calculate the critical wind speed of conductor galloping through programming. The dates of wind tunnel test and calculation in this paper can be used in the antigalloping design of transmission lines.

Finite Element Model of Human Cochlea Considering of the Helicotrema Size

2013 ◽  
Vol 456 ◽  
pp. 576-581 ◽  
Author(s):  
Li Fu Xu ◽  
Na Ta ◽  
Zhu Shi Rao ◽  
Jia Bin Tian
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Basilar Membrane ◽  
Round Window ◽  
Element Model ◽  
Oval Window ◽  
Fe Model ◽  
Cochlear Duct ◽  
Human Cochlea ◽  
Set Up

A 2-D finite element model of human cochlea is established in this paper. This model includes the structure of oval window, round window, basilar membrane and cochlear duct which is filled with fluid. The basilar membrane responses are calculated with sound input on the oval window membrane. In order to study the effects of helicotrema on basilar membrane response, three different helicotrema dimensions are set up in the FE model. A two-way fluid-structure interaction numerical method is used to compute the responses in the cochlea. The influence of the helicotrema is acquired and the frequency selectivity of the basilar membrane motion along the cochlear duct is predicted. These results agree with the experiments and indicate much better results are obtained with appropriate helicotrema size.

Study on the Prediction of Drilling Forces on Cortical Bone Based on Finite Element Simulation

2013 ◽  
Vol 589-590 ◽  
pp. 157-162
Author(s):  
Ya Hui Hu ◽  
Qing Yun Zhang ◽  
Xiao Yu Yue
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Feed Rate ◽  
Orthogonal Experiment ◽  
Element Model ◽  
Drilling Speed ◽  
Drilling Force ◽  
Drill Diameter ◽  
Potential Damage ◽  
Set Up

The changes of drilling forces during bone drilling provide a useful index for evaluating the risk of potential damage to the bone. The aim of the work is that an elastic-plastic dynamic finite element model is used to simulate the process of a drill bit drilling through the bone. The finite element model was set up in the Abaqus6.11; the prediction model of the drilling force was gotten by using the regression orthogonal experiment and data processing software Matlab7.0. Diverse values of drilling speed, feed rate and drill diameter are important factors which will lead to changes in the drilling forces. By controlling the drilling parameters can obtain the optimal drilling force. The results show that the diameter has the greatest influence on the drilling force, the drilling speed the second, the feed rate the last.

Development on Environmental Geotechnology for Overhead Transmission Line Foundation Engineering in China

2012 ◽  
Vol 610-613 ◽  
pp. 2813-2818
Author(s):  
Xian Long Lu ◽  
Zeng Zhen Qian
Keyword(s):  
Transmission Line ◽  
Environmental Protection ◽  
Transmission Lines ◽  
Water Conservation ◽  
Design Method ◽  
Foundation Engineering ◽  
Foundation Construction ◽  
Overhead Transmission Line ◽  
Tower Foundation ◽  
Soil And Water

This paper presents the concept and the fundamental issues and the development on the environmental geotechnology in transmission lines foundation engineering. Namely, environmental geotechnology and theory is to study the restriction effects of environment on the transmission line routes, foundation selection and reliability, to predict the results of transmission line foundation construction on the environment, and to study on countermeasures of environmental protection in transmission foundation engineering. And then, from the above three aspects, the design method combined strength and displacement for tower foundation, the selection on foundation types and technical scheme for transmission line tower, and the countermeasures for soil and water conservation, the author introduces the development and practice of environmental geotechnology for transmission lines foundation engineering in China.

Carbon Nanotube Composites for Vibration Damping

2008 ◽  
Vol 47-50 ◽  
pp. 817-820 ◽  
Author(s):  
R.L. Dai ◽  
W.H. Liao
Keyword(s):  
Carbon Nanotube ◽  
Epoxy Resin ◽  
Dynamic Properties ◽  
Element Model ◽  
Vibration Damping ◽  
Segment Length ◽  
Pure Epoxy ◽  
Nanotube Composites ◽  
Carbon Nanotube Composites ◽  
Set Up

It has been found that the composites of carbon nanotubes (CNTs) and epoxy resin could greatly enhance damping ability while the stiffness is kept high. In this paper, carbon nanotube enhanced epoxy resin is fabricated. A testing apparatus for obtaining composite dynamic properties is set up. In particular, the loss factors are measured. Experimental results show that CNT additive can provide the composite with several times higher damping as compared with pure epoxy. A finite element model is built to simulate the composite damping. CNT diameter and segment length are investigated using the developed model. Results show that composite damping is insensitive to CNT segment length while the effect of CNT diameter on composite damping is significant.

scholarly journals Collapse Analysis of a Transmission Tower-Line System Induced by Ice Shedding

2021 ◽  
Vol 9 ◽  
Author(s):  
Jiaxiang Li ◽  
Biao Wang ◽  
Jian Sun ◽  
Shuhong Wang ◽  
Xiaohong Zhang ◽  
...  
Keyword(s):  
Finite Element ◽  
Transmission Lines ◽  
Progressive Collapse ◽  
Element Model ◽  
Transmission Tower ◽  
Line System ◽  
Finite Element Software ◽  
Transmission Towers ◽  
Ice Shedding ◽  
The Impact

Ice shedding causes transmission lines to vibrate violently, which induces a sharp increase in the longitudinal unbalanced tension of the lines, even resulting in the progressive collapse of transmission towers in serious cases, which is a common ice-based disaster for transmission tower-line systems. Based on the actual engineering characteristics of a 500 kV transmission line taken as the research object, a finite element model of a two-tower, three-line system is established by commercial ANSYS finite element software. In the modeling process, the uniform mode method is used to introduce the initial defects, and the collapse caused by ice shedding and its influencing parameters are systematically studied. The results show that the higher the ice-shedding height is, the greater the threat of ice shedding to the system; furthermore, the greater the span is, the shorter the insulator length and the greater the dynamic response of the line; the impact of ice shedding should be considered in the design of transmission towers.

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