Vibration characteristics of a cooling-tower shell

Juhásová, E.; Bittnar, Z.; Fischer, Ondřej

doi:10.1016/0167-6105(83)90067-3

Cited by 8 publications

(2 citation statements)

References 6 publications

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“…The top of the shell is also thickened to reduce the stress levels, which, in turn, leads to increased design moments due to increased stiffness. Juhasova et al 4 studied the ring resonance vibration characteristics of a fullscale cooling tower using ambient vibrations and also using a mechanical exciter. The experimentally obtained vibration characteristics were observed to be comparable to those obtained through finite element analysis.…”

Section: Compass Of the Present Studymentioning

confidence: 99%

Experimental Determination of Wind-Induced Response on a Model of Natural Draught Cooling Tower

Babu

Rajan

Harikrishna

et al. 2011

Experimental Techniques

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The detailed and well‐publicized documented paper by Bamu and Zingoni in 2005 on cooling‐tower collapses accentuates the effect of wind on the performance of cooling towers. As it is well established that wind‐tunnel tests on tower models result in a more realistic assessment of wind‐induced stresses, wind‐tunnel tests are conducted on aero‐elastic model of an isolated cooling tower and the cooling tower with surrounding structures. The details of the experimental programme, measurements, analysis, and results for both the isolated and interference cases are presented in this paper. Based on the analysis of experimental data, ring‐resonance frequencies, and mode shapes of the model, meridional (N) and hoop (N) stress resultants and interference factor due to the presence of surrounding buildings are evaluated. The values of N, N, ring‐resonance frequencies, and mode shapes for isolated model are further compared with the values obtained based on finite element analysis.

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Section: Compass Of the Present Studymentioning

confidence: 99%

Experimental Determination of Wind-Induced Response on a Model of Natural Draught Cooling Tower

Babu

Rajan

Harikrishna

et al. 2011

Experimental Techniques

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“…Very limited field measurements have been done regarding structural responses and dynamic characteristics. To the best of our knowledge, only Juhasova et al and Winney performed field measurements and modal recognition of two large cooling towers. The height of the tested towers was only 120 m, which is much smaller than the height of the current large cooling towers (≥190 m).…”

Section: Introductionmentioning

confidence: 99%

Identification of damping ratio and its influences on wind‐ and earthquake‐induced effects for large cooling towers

et al. 2018

Structural Design Tall Build

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Summary Standard 5% damping ratio for high‐rise concrete structures is generally used for dynamic analysis under the action of wind and earthquakes in the existing cooling tower regulations and researches. But considering the unique configuration and material attributes of large cooling towers, the actual damping ratio must be far smaller than the recommended. However, only a few field measurements of damping ratio for large cooling towers have been conducted; neither are there thorough investigation into the qualitative and quantification of wind and seismic effects under different damping ratio. To fill this gap, field measurements of a large cooling tower standing 179 m in northwestern China was performed and acceleration vibration signals at representative positions of the tower under ambient excitation were obtained. The vibration signals were preprocessed combining random decrement technique and natural excitation technique. Three pattern recognition methods (auto‐regressive and moving mean model, Ibrahim time domain, and spare time domain (STD)) were applied to analyze the frequencies, damping ratios, and modes of vibration for the first 10 order modes. Following the line of thought of modal combination, the equivalent synthetic damping ratio was derived. Under 5 damping ratios (0.5%, 1%, 2%, 3%, and 5%), a comparative analysis on the dynamic responses of the cooling tower to wind and single seismic loading by using full transient method was performed. On this basis, the patterns of influence of damping ratio on wind‐induced vibration, wind vibration coefficient, and time history and extrema of seismic responses were extracted. Finally, different combinations of dead weight, wind, temperature in winter, sunshine duration, and seismic intensity and those of accidental seismic effects (8 working conditions) were considered, using equivalent synthetic damping ratio and standard damping ratio. Thus, the most unfavorable working conditions were identified under actual and standard damping ratios for the large cooling tower. Our research findings provide reference for determining the value of damping ratio in large cooling towers and deepening the understanding on the influence mechanism of damping ratio.

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Finite element analysis of free-free shells of revolution

Heppler

Wahl

1992

Journal of Sound and Vibration

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Vibration characteristics of a cooling-tower shell

Cited by 8 publications

References 6 publications

Experimental Determination of Wind-Induced Response on a Model of Natural Draught Cooling Tower

Experimental Determination of Wind-Induced Response on a Model of Natural Draught Cooling Tower

Identification of damping ratio and its influences on wind‐ and earthquake‐induced effects for large cooling towers

Finite element analysis of free-free shells of revolution

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