scholarly journals Dynamic Response of Self-Supported Power Transmission Tower Subjected to Wind Action

2018 ◽  
Vol 7 (4.35) ◽  
pp. 476
Author(s):  
Nur Hamizah Hamzah ◽  
Fathoni Usman ◽  
Mohd Yazee Mat Yatim
Keyword(s):  
Dynamic Response ◽  
Dynamic Analysis ◽  
Power Transmission ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Time History ◽  
Transmission Tower ◽  
Electrical Transmission ◽  
Structural Dynamic ◽  
Wind Action

A power transmission tower carries electrical transmission conductor at adequate distance from the ground. It must withstand all nature’s forces besides its self-weight. In structural analysis, natural frequency, mode shape and damping ratio are used to define the structural dynamic properties which relate to the basic structural features. This paper described the dynamic analysis including the modal and the time history analysis on each segment of the self-supported transmission tower to understand its dynamic responses subjected to wind action. The factors such as different height above ground, a different value of wind speed and different wind angle of attack were included in this study to see the influence of those factors towards dynamic response of the structure. The contribution of the wind towards the displacement of the structure is determined in this study by comparing the result obtained in a linear static analysis which considered the load combination without and with the presence of wind action. It was found that displacement using dynamic analysis is bigger than static linear analysis. The result illustrates that the studied factors gave a significant effect on the dynamic response of the structure and the findings indicate that dynamic analysis is vital in structural design.

Structural Dynamic Response Monitoring of Power Transmission Tower

2011 ◽  
Vol 105-107 ◽  
pp. 986-989 ◽  
Author(s):  
Kai Quan Xia ◽  
Xue Wu Liu ◽  
Yun Liu
Keyword(s):  
Dynamic Response ◽  
Transmission Lines ◽  
Power Transmission ◽  
Structural Characteristics ◽  
Monitoring Program ◽  
Warning System ◽  
Vibration Sensor ◽  
Response Monitoring ◽  
Transmission Tower ◽  
Structural Dynamic

In order to study the dynamic response of power transmission lines under mechanical fault, the structural dynamic response monitoring indexes based on the requirement of field measurement were determined according to the structural characteristics of steel towers. The monitoring program was put forward in terms of the monitoring principle and basis of the sensors. The vibration characteristic, dynamic alignment and stress/strain are chosen to be the monitoring indexes. Considering the synchronization function of GPS system, the three monitoring indexes of the large span high voltage tower can be simultaneously monitored by using vibration sensor, GPS and strain sensor. The monitoring scheme can provide the theoretical base for the establishment of early warning system and the collection of dynamic response of steel tower during line break or tower collapse.

Analysis of Wind-Induced Vibration Response on a Tower Consisted of Steel Tubes and Angel Steels

2013 ◽  
Vol 405-408 ◽  
pp. 763-766
Author(s):  
Yan Zhong Ju ◽  
Xiao Lei Zhang
Keyword(s):  
Dynamic Response ◽  
Dynamic Analysis ◽  
Time History ◽  
Wind Load ◽  
Vibration Response ◽  
Response Analysis ◽  
Transmission Tower ◽  
Steel Tubes ◽  
Static Result ◽  
Tower Structure

tower consisted of steel tubes and angel steels has equal advantages which steel tube tower has and not easy to happen some bar breeze vibration,but but the wind vibration response for such transmission tower structure research is less. In the engineering background of a tower consisted of steel tubes and angel steels , set up the finite element model for transmission towers. Using Kaimal spectrum for numerical simulation of wind velocity time history. Of 90 ° Angle of wind direction wind to dynamic response are analyzed, the results show that for the displacement, the maximum of dynamic analysis results 88% larger than the result of the average wind, 53.7% larger than standard wind load static result; For axial force, the maximum of dynamic analysis results 147% larger than average the result of the wind, 108% larger than standard wind load static result. So in view of the transmission tower structure dynamic response analysis should be more precise.

Simulation of Time Histories of Second-Order Wave Effects by Pseudo-Linear Transformation

1995 ◽  
Vol 117 (2) ◽  
pp. 78-84
Author(s):  
Y. Li
Keyword(s):  
Dynamic Response ◽  
Time History ◽  
Second Order ◽  
Hilbert Transforms ◽  
Structural Dynamic ◽  
Quadratic Transformation ◽  
Wave Effects ◽  
Time Histories ◽  
Component Wave ◽  
The Time Domain

Simulation of the time histories of second-order wave effects is often performed by quadratic transformation of a wave time history. By the present approach, the quadratic transformation of waves is approximated by linear combinations of the products of component wave time records and their Hilbert transforms. The computational efficiency is greatly enhanced. The efficient quadratic transformation of a time history is for the time domain solution of structural dynamic response, and can also be used as a post-processor of the frequency domain solution for obtaining statistic parameters of dynamic response.

Structural Surrogate Model and Dynamic Response Prediction with Consideration of Temporal and Spatial Evolution: An Encoder–Decoder ConvLSTM Network

2021 ◽  
pp. 2150140
Author(s):  
Hong Peng ◽  
Jingwen Yan ◽  
Ying Yu ◽  
Yaozhi Luo
Keyword(s):  
Dynamic Response ◽  
Surrogate Model ◽  
Structural Model ◽  
Short Term Memory ◽  
Time History ◽  
Response Prediction ◽  
Surrogate Models ◽  
Hybrid Network ◽  
Spatiotemporal Evolution ◽  
Structural Dynamic

In this paper, a new deep learning framework named encoding convolution long short-term memory (encoding ConvLSTM) is proposed to build a surrogate structural model with spatiotemporal evolution of structure, estimate the structural spatiotemporal state and predict the dynamic response under similar future dynamic load conditions. The main work of this study includes: (a) The spatiotemporal response tensor database is developed using discrete-time history data of structural dynamic response. (b) As an extension of LSTM, convolution operation is combined with LSTM network to construct structural surrogate model from the spatiotemporal evolution structural performance. (c) To enhance the anti-interference ability of structural surrogate models, a new three-layer encoding layer is added for denoising autoencoders of the hybrid network. The influence of building types and input noise on the accuracy and antinoise performance of the surrogate models are analyzed through the dynamic response prediction of a frame-shear wall, a cylindrical, and a spherical reticulated shell structure. As a testbed for the proposed network, a case study is performed on a laboratory stadium structure. The results demonstrate that the developed surrogate model can predict the structural dynamic response precisely with more under 30% noise interference.

The Analysis of Galloping-Endurance Character of 500kV Power Transmission Tower

2013 ◽  
Vol 333-335 ◽  
pp. 2123-2129
Author(s):  
Xiao Hui Yang ◽  
Bo Zhang ◽  
Wen Juan Lou ◽  
Zheng Cai Fu
Keyword(s):  
Dynamic Response ◽  
Transmission Line ◽  
Power Transmission ◽  
Power Grid ◽  
Endurance Performance ◽  
Ice Thickness ◽  
Transmission Tower ◽  
Laboratory Modeling ◽  
Maximum Loading ◽  
Vibration Model

With transmission line galloping occurring frequently in recent years, the phenomenon of tower damaged by galloping has become more and more serious, even with the whole tower collapsed during galloping. According to the statistic and analysis on the towers in 500kV transmission line of Henan power grid, which had been damaged by the galloping accidents in the winter of 2009 to 2010, The galloping section of 500kV Kai-Xiang Line with the typical impaired character had been selected for laboratory modeling and test. Through a series of tests, the maximum loading position and the vibration model for tower had been found, and the changing character of towers dynamic response with ice thickness, galloping amplitude and frequency analyzed. The loading-endurance character of rod and bolts joint, as the major components of tower, had been tested and analyzed respectively. The bolts joints, had been proved as the weakest point for galloping-endurance performance of the whole tower. The study stated in this paper would provide guidance and suggestion to the alteration on galloping prevention and controlling for transmission line. It was also shown that, developing the study on the locking performance of bolts joints on tower is quite essential.

Effect of flexible pin on the dynamic behaviors of wind turbine planetary gear drives

2012 ◽  
Vol 227 (1) ◽  
pp. 74-86 ◽  
Author(s):  
CaiChao Zhu ◽  
XiangYang Xu ◽  
Teik Chin Lim ◽  
XueSong Du ◽  
MingYong Liu
Keyword(s):  
Dynamic Response ◽  
Power Transmission ◽  
Equations Of Motion ◽  
Planetary Gear ◽  
Spur Gear ◽  
Contact Forces ◽  
Structural Dynamic ◽  
Torque Density ◽  
Position Errors ◽  
Planet Gear

Flexible pins eliminate the need for straddle mounting, and therefore enable the maximum possible number of planets to be used for any particular epicyclic ratio of power transmission systems. Having more planet gears will significantly increase the input torque density. In this type of design, the pin stiffness and position tolerances are important parameters as they affect the dynamic performances significantly. The present study addresses this issue by modeling, the design of double cantilevered flexible pin, and analyzing the contributions of pin stiffness and misalignment applying the lumped parameter approach. The proposed model formulates the coupled lateral-torsional dynamic response of a planetary spur gear, including the effects of mesh stiffness and phasing as a function of pin error. The resultant equations of motion are applied to examine the effects of pin stiffness and position errors on the natural modes and structural dynamic response. The effects of pin stiffness on deviation of the tooth contact forces of the sun-planet and ring-planet gear pairs are analyzed to understand the relationship between mesh characteristic and input speed variations. The calculated supporting forces of the planet gear are examined to understand the load sharing characteristic due to pin errors, pin stiffness and input load of the power transmission system.

scholarly journals A New Method to Calculate Additional Damping Ratio considering the Effect of Excitation Frequency

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Weizhi Xu ◽  
Dongsheng Du ◽  
Shuguang Wang ◽  
Weiwei Li
Keyword(s):  
Dynamic Response ◽  
Ground Motion ◽  
Calculation Method ◽  
Response Spectrum ◽  
Damping Ratio ◽  
Excitation Frequency ◽  
Structural Dynamic ◽  
Important Indicator ◽  
Simplified Calculation ◽  
Simplified Calculation Method

The additional damping ratio (ADR) is an important indicator for evaluating the damping effect of structures with energy-dissipation devices. Most existing methods for determining the ADR require an analysis of the structural dynamic response and complex iterative calculations. An innovative simplified calculation method for determining the ADR of a structure supplemented by nonlinear viscous dampers is proposed. This method does not require the dynamic response of the structure to be calculated and only requires the structural characteristics, excitation frequency, and damper parameters. In this study, several typical calculation methods for the ADR were analysed. Then, a calculation formula for the ADR was derived with consideration of harmonic excitation under the condition where the excitation frequency is equal to the structural natural frequency, without calculation of the structural dynamic response or an iterative process. The effect of the excitation frequency on the calculated value of the ADR with different damping exponents was studied. Accordingly, the response spectrum average period (RSAP) was considered as the excitation period of ground motion to evaluate the excitation frequency, and a simplified calculation method for the ADR considering the effect of the excitation frequency characterised by the RSAP of the ground motion was established. Finally, the accuracy and effectiveness of the proposed method were verified by comparison with ADRs calculated using other methods.

Development of an equivalent static method for the approximation of the dynamic response of offshore structures

2019 ◽  
Vol 36 (4) ◽  
pp. 1121-1141 ◽  
Author(s):  
Apostolos Koukouselis ◽  
Konstantinos Chatziioannou ◽  
Euripidis Mistakidis ◽  
Vanessa Katsardi
Keyword(s):  
Dynamic Response ◽  
Dynamic Analysis ◽  
Earthquake Engineering ◽  
Structural Model ◽  
Computational Cost ◽  
Time History ◽  
Offshore Structures ◽  
Design Approach ◽  
Wave Loading ◽  
Content Type

Purpose The design of compliant towers in deep waters is greatly affected by their dynamic response to wave loads as well as by the geometrical and material nonlinearities that appear. In general, a nonlinear time history dynamic analysis is the most appropriate one to be applied to capture the exact response of the structure under wave loading. However, this type of analysis is complex and time-consuming. This paper aims to develop a simplified methodology, which can adequately approximate the maximum response yielded by a dynamic analysis by means of a static analysis. Design/methodology/approach Various types of time history dynamic analysis are first applied on a detailed structural model, ranging from linear to fully nonlinear, that are used as reference solutions. In the sequel, a simplified analysis model is formulated, capable of reproducing the response of the entire structure with significantly reduced computational cost. In the next stage, this model is used to obtain the linear and nonlinear response spectra of the structure. Finally, these spectra are used to formulate a simplified design approach, based on equivalent static loads. Findings This simplified design approach produces good results in cases that the response is mainly governed by the first eigenmode, which is the case when compliant towers are considered. Originality/value The present paper borrows ideas from the area of earthquake engineering, where simplified methodologies can be used for the design of a certain class of structures. However, the development of a simplified methodology for the approximation of the dynamic behavior of offshore structures under wave loading is a much more complex problem, which, to the authors’ knowledge, has not been addressed till now.

Dynamic Response analysis of Long Span Transmission Tower under Tornado

2012 ◽  
Vol 450-451 ◽  
pp. 1257-1260
Author(s):  
Qiang Gao ◽  
Chao Ren ◽  
Yang Xu ◽  
Zhen Yao Liu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Dynamic Response ◽  
Dynamic Analysis ◽  
Wind Direction ◽  
Response Analysis ◽  
Transmission Tower ◽  
Dynamic Response Analysis ◽  
Long Span ◽  
Element Method

To study the effects of tornado on long span transmission tower, a model of the tower is built and the features of the tornado are considered. Three different wind cases are discussed in dynamic analysis with finite element method. The analysis results show that dynamic response is more significant at 45° wind direction.

Simulation and Experiential Research for Broken Conductor Load of Suspension Towers of UHVDC Power Transmission

2012 ◽  
Vol 249-250 ◽  
pp. 798-803
Author(s):  
Zi Fu Zhang ◽  
Zeng Lu Mo ◽  
Jing Du Geng
Keyword(s):  
Dynamic Response ◽  
Transmission Line ◽  
Transmission Lines ◽  
Power Transmission ◽  
Dynamic Strain ◽  
Power Transmission Lines ◽  
Transmission Tower ◽  
Research Results ◽  
Experiential Research ◽  
First Time

The breakage of conductor/ground wire seriously affects the secure operation of transmission line. According to the features of UHVDC power transmission lines, the broken conductor model for bundled conductors of continuous span is built and the broken conductor load is calculated; A simulating test was carried out the first time in China for a series of "broken conductor" events on one continuous span on the field to study the dynamic response of the transmission tower because of impact, then the dynamic strain and displacement were obtained. On the basis of the simulation and experiential research results, the paper discussed about the rational values of broken wire loads for the suspension towers of UHVDC.

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