Papers by Author: Li Li

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Authors: Li Li, Wei Jiang, Hua Jin Cao
Abstract: A nonlinear finite element model of transmission tower-line coupling system including transmissions, towers and insulators is established based on ANSYS in this paper. The restarting technology is proposed to solve the vertical, horizontal and torsional galloping of the transmission conductors. Under the condition of different wind velocity, galloping of tower line system is performed to get amplitude of the transmissions and internal forces of the transmission towers. Based on the typical case, the galloping control measures of using interphase spacers and multi-point weighting are performed. Various layouts projects of the galloping control measures are carried out and the effective ones are attained.
2666
Authors: Yuan Kun Chen, Li Li, Kun Ye, Peng Yin
Abstract: In this paper, laboratory tests on conductor aeolian vibration were designed and carried out, through which the power dissipation characteristics of conductor self-damping and wire dampers(bretelles) were investigated. In addition, the theoretical method was established to estimate the power dissipated by wire damper. The results show that conductor tension and vibration frequency have great influences on its self-damping property; furthermore, the results present that the natural frequency of wire damper is related with its length and the length of wire damper has significant impact on its anti-vibration effect. The theoretical method for calculating the power dissipated by wire damper was verified to be reliable by the test results. These conclusions can provide references for the research and anti-vibration design of transmission line engineering.
2290
Authors: Li Li, Zi Dong Hu, Zhi Yuan Cheng, Wei Jiang
Abstract: A two-node cable element which the axial torsion and geometrical nonlinear were considered was developed based on the update Lagrange formulation, and a model of multi-span transmission line for galloping analysis was established. A nonlinear numerical simulation of single iced conductor galloping was proposed. Using computational fluid dynamic, the aerodynamic coefficient of iced conductor with different wind attack angle was simulated. According to the finite element model of multi-span transmission line and aerodynamic coefficient curve, the galloping of iced conductor through the method of fourth-ordered Runge-Kutta method was presented. By the comparison with the classical examples, the results indicated that the presented method are efficient and reliable.
2676
Authors: Li Li, Zhi Yuan Cheng, Zi Dong Hu
Abstract: The general expression of Lagrange nonlinear cable element is established firstly by using virtual work principle. On the basis of the theory, the specific expression of a two-node cable element having rotational degree of freedom is derived and the non-linear finite element model of multi-span transmission line for galloping analysis was established. In addition, the aerodynamic coefficient of iced conductor under different wind attack angle was obtained through computational fluid dynamics method. Based on the finite element model and aerodynamic characteristics of the iced conductor, the Runge-Kutta method was applied to carried out non-linear numerical simulation of iced conductor galloping and the Matlab program was compiled. The galloping of the multi-span transmission line crossing Hanjiang River was analyzed. The results indicate that the presented method can simulate the galloping process effectively and it can provide the basic references for further research of preventing galloping.
2671
Authors: Wen Jing Liu, Li Li, Kun Ye
Abstract: LRB base isolation technology is different from the traditional continuous girder structure system, and shows good isolation performances. However, because fixed piers were canceled and all bearings were LRB, it is often considered that the reliability of structure might be reduced. Therefore, the reliability of LRB continuous girder bridges subject to seismic excitation was systematically studied from different indicators for the first time in this paper, the world's first double traffic double deck isolated continuous girder bridge – Dongjiang double-layer-pier isolated approach bridge in Dongguan of Guangdong province was adopted as study case. The results shows that, when the effect of pile-soil interaction is considered, LRB system still has a very good isolation performance; pounding subjected to seismic must be analyzed; dynamic stability needs checking when higher piers and larger earthquake displacement. Generally speaking, the reliability of LRB continuous girder bridges subject to seismic excitation won’t be reduced.
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