【摘要】： 大跨空間鋼結構多用于體育館、會展中心等城市標志性建筑,其結構體型龐大,造型獨特,形式新穎。為了保證結構的安全性,需要對大跨空間鋼結構進行健康監(jiān)測和損傷預警。本文主要研究如何由加速度時程響應提取結構損傷敏感指標并分離環(huán)境變化和監(jiān)測信號噪聲的影響,統(tǒng)計判別結構的工作狀態(tài),主要研究內(nèi)容如下: 研究了由加速度時程響應建立ARMA模型。理論分析了ARMA模型的適合階次,闡明了ARMA模型的階次由結構參與振動的振型數(shù)決定。提出了基于遺傳算法的ARMA定階方法,首先根據(jù)AR模型的階次確定ARMA模型階次的范圍,然后應用遺傳算法搜索ARMA模型的階次。K8型網(wǎng)殼的數(shù)值算例表明,所提方法減少定階運算量,能夠?qū)崿F(xiàn)ARMA模型的快速定階。 分別研究了以AR系數(shù)和脈沖響應為結構損傷敏感指標,表征結構的工作狀態(tài),并提出了基于主成分分析和假設檢驗的統(tǒng)計判別方法。簡支梁和K8型網(wǎng)殼的數(shù)值算例分別表明,以AR系數(shù)為結構損傷敏感指標,可以預警簡支梁的微小損傷和網(wǎng)殼結構的比較嚴重的損傷,該指標的敏感性隨著結構復雜程度增加有所降低;以脈沖響應為結構損傷敏感指標,能夠較好的預警網(wǎng)殼結構的微小損傷。 基于“水立方”結構的數(shù)值模型,研究了脈沖響應作為結構損傷敏感指標對監(jiān)測信號噪聲的魯棒性。數(shù)值算例表明,該指標能夠預警“水立方”結構一定程度的損傷,并對信號噪聲有較好的魯棒性。提出采用支持向量機回歸得到脈沖響應以溫度和風速為自變量的函數(shù)關系,以支持向量機的訓練殘差建立統(tǒng)計過程控制圖,分離環(huán)境因素對結構工作狀態(tài)的影響。
[Abstract]:Large span space steel structures are used in iconic buildings such as gymnasium and exhibition center. Their structures are large, unique in shape and novel in form. In order to ensure the safety of the structure, it is necessary to carry out health monitoring and damage warning for long span space steel structures. This paper mainly studies how to extract structural damage sensitive index from acceleration time history response, separate the influence of environment change and monitoring signal noise, and judge the working state of structure statistically. The main contents are as follows: the ARMA model is established from the acceleration time history response. The suitable order of ARMA model is analyzed theoretically. It is clarified that the order of ARMA model is determined by the number of modes in which the structure takes part in the vibration. The ARMA order determination method based on genetic algorithm is proposed. Firstly, the range of ARMA model order is determined according to the order of AR model, and then the numerical example of searching ARMA model order. K8 reticulated shell shows that the proposed method reduces the number of order determination operations. The fast order determination of ARMA model can be realized. AR coefficient and impulse response are used as damage sensitive indexes to characterize the working state of the structure, and a statistical discriminant method based on principal component analysis and hypothesis test is proposed. Numerical examples of simply supported beam and K8 type reticulated shell show that using AR coefficient as the sensitive index of structural damage, the small damage of simply supported beam and the severe damage of reticulated shell structure can be forewarned. The sensitivity of the index decreases with the increase of structural complexity, and the pulse response is used as the sensitive index of structural damage, which can be used to predict the small damage of latticed shell structure. Based on the numerical model of "water cube" structure, the robustness of impulse response as a structural damage sensitive index to monitoring signal noise is studied. Numerical examples show that the index can warn the damage of "water cube" structure to a certain extent and has good robustness to signal noise. The function relation of impulse response with temperature and wind speed as independent variables is obtained by using support vector machine regression. The statistical process control chart is established by training residual of support vector machine, and the influence of environmental factors on the working state of structure is separated.
【學位授予單位】：哈爾濱工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2010
【分類號】：TU391;TU312.3

【引證文獻】

相關碩士學位論文 前1條

1 黃振興;震后橋梁結構時頻域損傷診斷研究[D];西南交通大學;2012年

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本文編號：2213010