Valuation method for general equivalent damping ratio of large-scale cooling tower based on field measurement

Abstract

The invention provides a valuation method for a general equivalent damping ratio of a large-scale cooling tower based on field measurement. The valuation method for the general equivalent damping ratio of the large-scale cooling tower based on the field measurement comprises the following steps: a, building a finite element model of the large-scale cooling tower; b, performing dynamic characteristic analysis on the finite element model; c, extracting mass participating coefficient ratios of vibration modes of all orders; d, performing the field measurement on the large-scale cooling tower to obtain a structural damping ratio by modal analysis; e, by considering all order damping ratios and vibration mode mass participating coefficients of corresponding orders, calculating to obtain equivalent modal damping ratios of all the orders; f, performing integration analysis to obtain the general equivalent damping ratio of an integral structure of the large-scale cooling tower. By using the valuation method for the general equivalent damping ratio of the large-scale cooling tower based on the field measurement, the limitation that a value range or a mean value of a damping ratio is only given out in dynamic analysis of a traditional cooling tower structure is overcome, and the accuracy and the reliability of wind resistance and earthquake proof analysis of the large-scale cooling tower are effectively improved.

Description

technical field [0001] The invention belongs to the technical field of cooling towers, and in particular relates to a method for obtaining a comprehensive equivalent damping ratio of a large cooling tower based on on-site actual measurement. Background technique [0002] In recent years, with the increase in the capacity of generating units and the implementation of the project of "upperizing the large and suppressing the small" in the power industry, the spraying area and height of the cooling tower have also increased. During this period, a number of large-scale cooling tower projects exceeding the standard (190m) height limit emerged. Currently, the intercooling tower (220m) of Shanxi Lu'an Changzi Gaohe Power Plant and the Pengze Nuclear Power Wet Cooling Tower (215m) are under construction. [0003] The main structure of the super-large cooling tower is a typical towering, thin-walled shell structure, which has the characteristics of large flexibility and low natural fr...

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Problems solved by technology

[0006] Few scholars at home and abroad have conducted in-depth research on the determination of the damping ratio of super-large cooling towers. The current dynamic analysis still uses the damping ratio of 5% for concrete structures in the "Code for Seismic Design of Buildings" (GB50011-2010), which cannot well reflect the large-scale cooling tower. Due to the damping characteristics of the cooling tower structure itself, the calculation results are difficult to truly reflect the dynamic response of the structure under the action of wind and earthquake

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