【摘要】：空間網(wǎng)架結(jié)構(gòu)為高次超靜定結(jié)構(gòu),結(jié)構(gòu)形式復(fù)雜,可達到較大的跨度,多用于重要的公共建筑中。網(wǎng)架結(jié)構(gòu)由于施工疏忽、使用不當(dāng)、偶然荷載等因素造成的損傷難以完全避免,一旦結(jié)構(gòu)損傷未被及時發(fā)現(xiàn),則隨時可能發(fā)生工程事故。此類事故一般都會帶來巨大的財產(chǎn)損失和人身危害,因此對空間網(wǎng)架結(jié)構(gòu)損傷檢測進行研究尤為重要。針對此工程問題,本文主要進行以下幾方面的研究:(1)本文對現(xiàn)有損傷檢測方法進行歸納總結(jié),發(fā)現(xiàn)空間網(wǎng)架結(jié)構(gòu)的損傷識別技術(shù)尚未成熟。由于網(wǎng)架結(jié)構(gòu)節(jié)點和桿件眾多,其損傷識別多數(shù)停留在數(shù)值模擬階段。故本文建立了網(wǎng)架實驗?zāi)Ｐ?對損傷前后的網(wǎng)架結(jié)構(gòu)分別經(jīng)過應(yīng)變測試和加速度測試,采取各桿件的應(yīng)變值和加速度值。再經(jīng)過模態(tài)分析處理,得到實驗網(wǎng)架結(jié)構(gòu)損傷前后的前八階固有頻率和對應(yīng)振型。(2)分別運用基于坐標(biāo)模態(tài)確認準則的損傷識別方法、基于曲率模態(tài)差的損傷識別方法和基于模態(tài)柔度比變化率的損傷識別方法,對實驗結(jié)構(gòu)的振型數(shù)據(jù)深入分析,得出損傷識別結(jié)果。運用基于應(yīng)變模態(tài)的損傷識別方法對實驗結(jié)構(gòu)的應(yīng)變數(shù)據(jù)進行分析,也得出其損傷識別結(jié)果。從這四個損傷判別結(jié)果來看,針對本網(wǎng)架結(jié)構(gòu),各損傷指標(biāo)均存在或多或少的誤判行為。(3)為了提高損傷識別的精度,本文提出把數(shù)據(jù)融合方法引入到損傷識別領(lǐng)域。對數(shù)據(jù)融合的基本原理、D-S證據(jù)理論的識別框架、信任函數(shù)等基本概念和其合成規(guī)則等進行了簡要的介紹。運用D-S證據(jù)理論算法,對上述四種損傷識別結(jié)果分別進行信任分配后,再用合成規(guī)則進行組合,最終得到更加協(xié)同、精確的判斷結(jié)果。經(jīng)過三個層次的多次融合,得到對128根桿件發(fā)生損傷的信任程度,準確的判斷出結(jié)構(gòu)在63號桿位置處發(fā)生了損傷。這與實驗情況是相符的。本文在對空間網(wǎng)架結(jié)構(gòu)損傷識別的數(shù)據(jù)融合研究中,針對各種單一損傷識別指標(biāo)對網(wǎng)架結(jié)構(gòu)存在誤判行為,提出把D-S數(shù)據(jù)融合算法應(yīng)用到空間網(wǎng)架結(jié)構(gòu)的損傷識別中。其理論意義明確并在實驗中得到了驗證。事實證明,此方法可以準確的識別出損傷位置,對空間網(wǎng)架結(jié)構(gòu)的損傷識別研究具有明顯的理論意義和實用價值。
[Abstract]:The space truss structure is a high order statically indeterminate structure with complex structure form, which can reach a large span, and is mostly used in important public buildings. It is difficult to avoid the damage caused by some factors, such as careless construction, improper use and accidental load, etc. Once the structural damage is not detected in time, engineering accidents may occur at any time. This kind of accident usually brings huge property loss and personal harm, so it is very important to study the damage detection of space truss structure. Aiming at this engineering problem, this paper mainly studies the following aspects: (1) this paper summarizes the existing damage detection methods, and finds that the damage identification technology of space truss structures is not yet mature. Because of the large number of joints and members of the truss structure, the damage identification of the truss structure is mostly in the stage of numerical simulation. Therefore, the experimental model of grid structure is established in this paper. The strain and acceleration of the truss before and after damage are measured, respectively, and the strain and acceleration of each member are taken. After modal analysis, the first eight natural frequencies and corresponding modes before and after damage are obtained. (2) the damage identification method based on coordinate modal confirmation criterion is used respectively. The damage identification method based on curvature modal difference and the damage identification method based on the change rate of modal flexibility ratio are used to analyze the modal data of experimental structures and obtain the damage identification results. The strain data of experimental structures are analyzed by using the damage identification method based on strain mode, and the damage identification results are also obtained. According to the results of these four damage discriminations, each damage index has more or less misjudgment behavior. (3) in order to improve the accuracy of damage identification, the data fusion method is introduced into the field of damage identification. The basic principles of data fusion, such as the recognition framework of D-S evidence theory, the basic concepts of trust function and its composition rules, are briefly introduced. The D-S evidence theory algorithm is used to assign the above four damage identification results respectively and then combine them with the synthesis rules to obtain more cooperative and accurate judgment results. After multiple fusion of three levels, the degree of trust in 128 bars is obtained, and the damage of the structure at the 63 bar position is accurately judged. This is consistent with the experiment. In this paper, in the research of data fusion for damage identification of space truss structures, a D-S data fusion algorithm is applied to the damage identification of space truss structures in view of the misjudgment behavior of each single damage identification index. Its theoretical significance is clear and verified in the experiment. It has been proved that this method can accurately identify the damage location and has obvious theoretical significance and practical value for the damage identification of space truss structures.
【學(xué)位授予單位】：西安建筑科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TU317;TU356

【引證文獻】

相關(guān)期刊論文 前1條

1 成浩;張波;朱麗華;;某食堂鋼結(jié)構(gòu)網(wǎng)架鑒定與分析[J];陜西理工學(xué)院學(xué)報(自然科學(xué)版);2016年02期

相關(guān)碩士學(xué)位論文 前1條

1 林健;某螺栓球節(jié)點網(wǎng)架廠房坍塌事故分析[D];太原理工大學(xué);2016年

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本文編號：2227776