Frequency analysis of a tower-cable coupled system

Park, Moo Yeol; Kim, Seock-Hyun; Paek, Insu; Cheng-xun, Cui

doi:10.1007/s12206-013-0423-1

Cited by 7 publications

(3 citation statements)

References 6 publications

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“…These properties make AM-series alloys generally unsuitable for use above 150°C, and even at this temperature, considerable losses in strength are evident, rendering them inadequate for major power train applications. [1][2][3][4][5][6][7] One possible approach to improving the thermal stability and creep resistance of these kinds of alloys involves introducing alloying elements with higher affinities to aluminum to suppress the formation of the Mg 17 Al 12 phase. Introducing secondary phase particles to pin the grain boundaries and prevent sliding phenomenon is another such approach.…”

mentioning

confidence: 99%

Effect of Combined Micro‐Alloying of Calcium and Bismuth on the Microstructure and Mechanical Properties of AM50 Magnesium Alloy

2014

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It is highly desirable to apply magnesium-based alloys, which are the lightest structural metallic materials, in structural parts because of their high strength-to-density ratio, high energy absorption, and good castability. AM-series magnesium alloys, which belong to the MgÀAl system, are the most widely used commercial magnesium alloys, but they have poor thermal stability of the Mg 17 Al 12 phase (with a eutectic temperature of 437°C), and their discontinuous precipitation can result in substantial grain boundary sliding at elevated temperatures. These properties make AM-series alloys generally unsuitable for use above 150°C, and even at this temperature, considerable losses in strength are evident, rendering them inadequate for major power train applications. [1][2][3][4][5][6][7] One possible approach to improving the thermal stability and creep resistance of these kinds of alloys involves introducing alloying elements with higher affinities to aluminum to suppress the formation of the Mg 17 Al 12 phase. Introducing secondary phase particles to pin the grain boundaries and prevent sliding phenomenon is another such approach. One significant discovery that has emerged from the considerable efforts expended more than 10 years is the beneficial effect of rare-earth elements (REs) or yttrium on the mechanical properties of magnesium alloys, including their strength and creep resistance of magnesium alloys. [8][9][10][11] For this reason, magnesium alloys with RE and with Y þ RE (WE) are widely used in several technological applications. However, RE and Y are usually considered to be too high priced.The addition of low-cost calcium, which provides a finer solidified microstructure in the Mg alloy, [12][13][14][15][16] is also an effective way to improve the mechanical properties of magnesium alloys at elevated temperatures. The addition of other inexpensive elements such as bismuth could significantly increase the tensile strength and creep resistance, as reported by Yuan et al. [17,18] However, very few current reports have addressed to the effects of the addition of calcium and bismuth to AM50 magnesium alloys on their microstructures and mechanical properties. Hence, to understand the function of new secondary phases in the microstructures on its properties of magnesium alloys, the present work attempts to analyze the relationship between the microstructure and the properties when both calcium and bismuth are added into an AM50 alloy, to obtain the optimal addition of calcium plus bismuth for AM50 alloy. This can provide the basis for further applications of high-temperature magnesium alloys. ExperimentalCommercial as-cast AM50 magnesium alloy ingot, highpurity (99.5%) calcium granules (99.5%), and bismuth granules (99.0%) were used to prepare the AM50-xBi-yCa alloy using a resistance crucible furnace melting under the protection of a mixed gas atmosphere of 99.5% CO 2 and 0.5% SF 6 (vol%). The chemical compositions of the experimental alloys with varying concentrations of calcium (0, 1, 2, and 3 wt %) and bis...

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mentioning

confidence: 99%

Effect of Combined Micro‐Alloying of Calcium and Bismuth on the Microstructure and Mechanical Properties of AM50 Magnesium Alloy

2014

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“…From the existing data [47,48], it can be concluded that the natural frequency of tower ranges from 2.43 Hz to 10.68 Hz, which belongs to the lower frequency. When the main frequency of the blasting vibration wave is in the range of 2-11 Hz, even if the vibration velocity is relatively smaller, it may cause damage to the tower.…”

Section: Test Resultsmentioning

confidence: 99%

Vibration Characteristic of High‐Voltage Tower Influenced by Adjacent Tunnel Blasting Construction

Duan

Lin

Lai

et al. 2019

Shock and Vibration

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e effects of tunnel blast excavation on the adjacent existing high-voltage tower are comprehensively studied for the Chashan highway tunnel project as a case study. To investigate the effect of blast-induced vibration from the tunnel on the adjacent existing tower, field tests and numerical simulations method were adopted to study the vibration velocity and vibration frequency of the existing tower. Moreover, the relationship between the transverse distance from the detonation center and the peak velocity is discussed in detail. e results showed that the peak velocity of the measuring point in tower foundation increases with the distance between the detonation center and tower foundation approaches, and the maximum velocity is appearing when detonation center is 0 m. Furthermore, the corresponding energy spectrum distributions of the existing tower under the effect of blast induced by vibration is also analyzed, and the main frequency of vertical vibration is generally higher than that of transverse vibration. On combining the peak velocity with the main frequency and the natural frequency of the tower, the safety evaluation of the blasting area is proposed, and the corresponding control measures of blasting vibration are put forward. A guideline for the blast safety zone is proposed based on vibration velocity, main frequency, and the quantity of explosive.

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“…Park et al. (2013) presented a Rayleigh–Ritz analytical model for obtaining the principal natural frequency of a wind turbine tower–cable coupled system composed of a turbine tower and four guy cables, modeling the cables as rods, without sag.…”

Section: Introductionmentioning

confidence: 99%

Analytical and experimental investigation of cable–beam system dynamics

Jalali

Rideout

2019

Journal of Vibration and Control

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Interactions between cables and structures affect the design and nondestructive testing of electricity transmission lines, guyed towers, and bridges. An analytical model for an electricity pole beam–cable system is presented, which can be extended to other applications. A cantilever beam is connected to two stranded cables. The cables are modeled as tensioned Euler–Bernoulli beams, considering the sag due to self-weight. The pole is also modeled as a cantilever Euler–Bernoulli beam and the equations of motion are derived using Hamilton’s principle. The model was validated with a reduced-scale system in the laboratory and a setup was designed to accurately measure the bending stiffness of the stranded cable under tension. It is concluded that the bending stiffness and sag of the cable have a significant effect on the dynamics of beam–cable structures. By adding the cable to the pole structure, some hybrid modes emerge in the eigenvalue solution of the system. Modes with antisymmetric cable motion are sag-independent and the modes with symmetric cable motion are dependent on the cable sag. The effect of sag on the natural frequencies is more significant when the bending stiffness of the cables is higher.

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Frequency analysis of a tower-cable coupled system

Cited by 7 publications

References 6 publications

Effect of Combined Micro‐Alloying of Calcium and Bismuth on the Microstructure and Mechanical Properties of AM50 Magnesium Alloy

Effect of Combined Micro‐Alloying of Calcium and Bismuth on the Microstructure and Mechanical Properties of AM50 Magnesium Alloy

Vibration Characteristic of High‐Voltage Tower Influenced by Adjacent Tunnel Blasting Construction

Analytical and experimental investigation of cable–beam system dynamics

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