本文選題：混凝土結(jié)構(gòu) + 細(xì)觀模型��； 參考：《江蘇大學(xué)》2017年碩士論文

【摘要】：本文提出了一種針對(duì)混凝土結(jié)構(gòu)損傷檢測(cè)的時(shí)間逆轉(zhuǎn)損傷成像方法。本文以檢測(cè)混凝土結(jié)構(gòu)中與骨料尺寸相近的微小損傷為目的,為了改進(jìn)先前研究中將混凝土結(jié)構(gòu)視為均質(zhì)材料而造成的研究實(shí)用性不足的缺點(diǎn),引入細(xì)觀混凝土隨機(jī)骨料模型。該模型將混凝土結(jié)構(gòu)視為由水泥漿基底、骨料及黏粘層組成的三相復(fù)合材料,基于Monte Carlo隨機(jī)樣本原理并結(jié)合Matlab軟件建立。在數(shù)值模擬分析中,將建立的細(xì)觀模型導(dǎo)入有限元分析軟件進(jìn)行超聲波場(chǎng)模擬。采用自適應(yīng)性強(qiáng)的時(shí)間逆轉(zhuǎn)模型(Time Reversed Model-TRM)進(jìn)行損傷定位,并提出了一種基于小波變換的峰值時(shí)刻波場(chǎng)成像方法。最終搭建實(shí)驗(yàn)平臺(tái)并澆筑真實(shí)混凝土試件進(jìn)行驗(yàn)證。實(shí)驗(yàn)結(jié)果表明時(shí)間逆轉(zhuǎn)模型對(duì)于復(fù)雜混凝土結(jié)構(gòu)的損傷定位具有強(qiáng)的適用性,基于小波變換的峰值時(shí)刻成像法能夠消除噪聲干擾提高成像精度。本文提出的基于細(xì)觀混凝土模型的時(shí)間逆轉(zhuǎn)損傷成像方法的主要研究?jī)?nèi)容有:1)依據(jù)真實(shí)混凝土試件的骨料級(jí)配曲線(xiàn)并結(jié)合骨料投放理論生成混凝土細(xì)觀幾何模型,基于Comsol with Matlab軟件的交互性,將建立的二維模型導(dǎo)入Comsol Multiphysics軟件進(jìn)行損傷及傳感器的設(shè)置和網(wǎng)格劃分以完善仿真模型。2)修正時(shí)間逆轉(zhuǎn)損傷成像模型(TRM),以用于混凝土結(jié)構(gòu)主動(dòng)損傷檢測(cè)研究。TRM分為正向檢測(cè)和逆時(shí)成像兩個(gè)部分:正向檢測(cè)過(guò)程通過(guò)單點(diǎn)激勵(lì)多點(diǎn)接收模式得到包含損傷散射回波信號(hào)的一系列結(jié)構(gòu)響應(yīng)信號(hào),從數(shù)值角度進(jìn)行時(shí)間反演并作為逆時(shí)過(guò)程的輸入信號(hào);逆時(shí)成像過(guò)程選用等效彈性參數(shù)模型,幾何尺寸與隨機(jī)骨料模型相同,時(shí)反信號(hào)在相應(yīng)幾何位置同時(shí)加載形成時(shí)反波場(chǎng),時(shí)反波場(chǎng)在損傷位置會(huì)發(fā)生干涉疊加從而導(dǎo)致能量峰值的出現(xiàn),通過(guò)確定干涉峰值時(shí)刻,并獲取該時(shí)刻對(duì)應(yīng)原始波場(chǎng)以及小波變換能量場(chǎng)完成成像。與原始數(shù)據(jù)波場(chǎng)圖相比,小波變換處理成像結(jié)果消除了雜波干擾,成像結(jié)果更加清晰。進(jìn)一步對(duì)等效彈性參數(shù)模型中等效彈性參數(shù)的取值進(jìn)行討論,并且在骨料尺寸范圍內(nèi)調(diào)整損傷大小以驗(yàn)證成像精度,結(jié)果顯示成像結(jié)果匹配度高,對(duì)于非均質(zhì)混凝土結(jié)構(gòu)的損傷檢測(cè)已很好滿(mǎn)足工程實(shí)際需求。3)搭建實(shí)驗(yàn)平臺(tái),澆筑混凝土試塊并預(yù)設(shè)通孔損傷,通過(guò)激勵(lì)超聲信號(hào)并接收結(jié)構(gòu)響應(yīng)信號(hào)獲取損傷散射回波,將損傷信號(hào)時(shí)反處理并在等效彈性參數(shù)模型中加載獲取時(shí)反波場(chǎng)數(shù)據(jù)并進(jìn)行小波變換處理,基于小波變換數(shù)據(jù)進(jìn)行峰值時(shí)刻波場(chǎng)成像,完成實(shí)驗(yàn)驗(yàn)證。
[Abstract]:This paper presents a time reversal damage imaging method for damage detection of concrete structures. In order to detect the small damage in concrete structure which is close to aggregate size, in order to improve the deficiency of research practicability caused by using concrete structure as homogenous material in previous studies, this paper introduces a meso-concrete random aggregate model. In this model, the concrete structure is regarded as a three-phase composite composed of cement slurry substrate, aggregate and viscous layer. It is based on Monte Carlo random sample principle and combined with Matlab software. In the numerical simulation, the established mesoscopic model is introduced into the finite element analysis software to simulate the ultrasonic field. The time Reversed Model-TRM (time Reversed Model-TRM) is used to locate the damage, and a peak time wave field imaging method based on wavelet transform is proposed. Finally, the experimental platform is built and the real concrete specimen is built for verification. The experimental results show that the time reversal model is applicable to the damage location of complex concrete structures, and the peak moment imaging method based on wavelet transform can eliminate the noise interference and improve the imaging accuracy. In this paper, the main research contents of time reversal damage imaging method based on meso-concrete model are: (1) according to the aggregate gradation curve of real concrete specimen and combining with aggregate dropping theory, the concrete meso geometric model is generated. Based on the interactivity of Comsol with Matlab software, The two-dimensional model is imported into the Comsol Multiphysics software for damage and sensor setting and meshing to perfect the simulation model. 2) the modified time reversal damage imaging model is used to study the active damage detection of concrete structures. Forward detection and inverse time imaging are two parts: the forward detection process obtains a series of structural response signals including the damage scattering echo signal by single point excitation multi-point receiving mode. Time inversion is carried out from a numerical point of view and used as the input signal of the inverse time process, the equivalent elastic parameter model is used in the inverse imaging process, and the geometric dimension is the same as that of the random aggregate model, and the time inverse signal is loaded at the corresponding geometric position at the same time to form the inverse wave field. The interference superposition of the time inverse wave field in the damage position leads to the appearance of the peak energy. By determining the interference peak time and obtaining the time corresponding to the original wave field and the wavelet transform energy field, the imaging is completed. Compared with the original data, the wavelet transform can eliminate the clutter, and the imaging result is clearer. Furthermore, the value of equivalent elastic parameters in the model of equivalent elastic parameters is discussed, and the damage size is adjusted within the size range of aggregate to verify the imaging accuracy. The results show that the imaging results have a high matching degree. For the damage detection of heterogeneous concrete structure, it has met the actual engineering demand. 3) build the experimental platform, put the concrete test block and preset the through hole damage, and obtain the damage scattering echo by exciting the ultrasonic signal and receiving the structural response signal. The damage signal is processed in time and the acquired inverse wave field data are loaded in the equivalent elastic parameter model and processed by wavelet transform. The peak time wave field is imaged based on the wavelet transform data and the experimental verification is completed.
【學(xué)位授予單位】：江蘇大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類(lèi)號(hào)】：TU37;TU317

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 楊華;李宗利;惠弘毅;;基于隨機(jī)骨料模型的混凝土彈性模量預(yù)測(cè)研究[J];長(zhǎng)江科學(xué)院院報(bào);2016年02期

2 呂曉光;王明泉;李光亞;;合成孔徑聚焦超聲成像在混凝土探傷中的應(yīng)用研究[J];圖學(xué)學(xué)報(bào);2014年06期

3 張俊;丁輝;張益成;石一飛;;相控陣超聲檢測(cè)的有限差分模擬及其在回波分析中的應(yīng)用[J];無(wú)損檢測(cè);2012年08期

4 王光榮;;基于Hilbert變換的信號(hào)包絡(luò)提取方法研究[J];中國(guó)科技信息;2012年01期

5 熊煒;周曾輝;余開(kāi)彪;吳亞平;羅煒;;基于彎曲路徑的混凝土超聲層析成像及其改進(jìn)[J];巖土力學(xué);2011年02期

6 魏東;周正干;;固體中脈沖超聲波傳播的有限差分模擬[J];航空學(xué)報(bào);2010年02期

7 王強(qiáng);袁慎芳;;無(wú)參考主動(dòng)Lamb波結(jié)構(gòu)損傷時(shí)反成像監(jiān)測(cè)方法[J];航空學(xué)報(bào);2010年01期

8 肖建莊;杜江濤;劉瓊;;基于格構(gòu)模型再生混凝土單軸受壓數(shù)值模擬[J];建筑材料學(xué)報(bào);2009年05期

9 王強(qiáng);袁慎芳;;復(fù)合材料板脫層損傷的時(shí)間反轉(zhuǎn)成像監(jiān)測(cè)[J];復(fù)合材料學(xué)報(bào);2009年03期

10 王強(qiáng);袁慎芳;;主動(dòng)Lamb波損傷成像監(jiān)測(cè)中的波包重建方法[J];宇航學(xué)報(bào);2009年03期

相關(guān)碩士學(xué)位論文 前3條

1 王磊;大型鑄鍛件超聲無(wú)損檢測(cè)技術(shù)研究[D];河北科技大學(xué);2013年

2 趙翔宇;高層結(jié)構(gòu)預(yù)拌混凝土施工質(zhì)量無(wú)損檢測(cè)評(píng)價(jià)研究[D];西安建筑科技大學(xué);2013年

3 廖寅;混凝土結(jié)構(gòu)超聲陣列探測(cè)成像方法研究[D];南昌航空大學(xué);2012年

，

本文編號(hào)：1797828