基于LHS冷却塔敏感性分析及频率估算

Sensitivity Analysis Based on Latin Hypercube Sampling Method and Frequency Estimation of Cooling Tower

现有冷却塔结构自振频率主要基于有限元分析手段,缺乏简单有效的冷却塔自振频率估算公式。为解决该问题,以国内某179m高的大型冷却塔为基准塔,首先,通过改变结构典型参数(塔高、喉部高度、喉部直径、进风口高度和支柱截面积)获得基准塔的38个模型并进行动力特性分析,同时提炼出基频和倾覆频率随结构参数的变化规律;然后,用扰动法和拉丁超立方抽样(Latin hypercube sampling,简称LHS)两种方法进行结构自振频率参数的敏感性分析,获取了不同阶数下各参数的敏感因子,在此基础上,创新性地拟合提出考虑敏感因子权重值的多参数基频和倾覆频率的实用估算公式;最后,验证自振频率估算公式的精度,选择课题组已有研究的冷却塔进行了误差分析。揭示结构参数对大型冷却塔自振频率的敏感性具有重要意义,可为冷却塔结构抗风抗震设计、动力特性优化设计等提供指导。

It is of great significance to reveal the sensitivity of structural parameters to the natural frequencies of large cooling towers,such as the wind resistance,seismic design and dynamic characteristics optimization design of cooling towers.The natural frequencies of the existing cooling towers are mainly obtained by finite element analysis,and there is no simple and effective formula for estimating the natural frequencies of the cooling towers.In order to resolve this problem,taking a large cooling tower as the reference tower,firstly,38 models of the reference tower are obtained by changing the typical parameters of the structure,and the dynamic characteristics are analyzed.The law of fundamental frequency and overturning frequency changing with the structure parameters is extracted.Then,the sensitivity of the structural natural frequency parameters is analyzed by perturbation and Latin hypercube sampling method,and the sensitive factors of various structural parameters under different orders are obtained.On this basis,the practical estimation formula of multi-parameter fundamental frequency and overturning frequency considering sensitivity factor weight is innovatively fitted.Finally,in order to verify the accuracy of the formula for the estimation of the natural frequencies,the error analysis of the cooling towers selected by the research group is carried out.