本文選題：超聲CT　切入點(diǎn)：正演模型　出處：《安徽理工大學(xué)》2015年碩士論文

【摘要】：混凝土結(jié)構(gòu)由于施工不當(dāng)和外力作用,及其建筑材料性質(zhì)的影響,造成內(nèi)部結(jié)構(gòu)的介質(zhì)隱患�；炷两Y(jié)構(gòu)中的介質(zhì)隱患主要有蜂窩空洞、裂縫和局部不密實(shí)。由于這些缺陷,使混凝土結(jié)構(gòu)的不完整,從而導(dǎo)致其抗壓抗拉強(qiáng)度和耐久性嚴(yán)重降低。因此需要對(duì)工程現(xiàn)場(chǎng)中混凝土構(gòu)件進(jìn)行快速檢測(cè),對(duì)保證工程建設(shè)的安全具有重要意義。目前混凝土無(wú)損檢測(cè)方法主要有回彈法、沖擊回波法和雷達(dá)法。這些方法在檢測(cè)過(guò)程中各具弊端,受限于探測(cè)混凝土表面質(zhì)量情況,不能反映混凝土介質(zhì)內(nèi)部情況、儀器比較昂貴且受鋼筋的影響較大,現(xiàn)場(chǎng)探測(cè)不好展開(kāi)以及對(duì)于尺度較小的介質(zhì)隱患分辨率較低。超聲波法檢測(cè)可以有效的解決這些問(wèn)題,此類方法因具有極強(qiáng)的穿透力、較高的分辨率、檢測(cè)設(shè)備簡(jiǎn)單、極易操作的特點(diǎn),因此在檢測(cè)成本上以及后期數(shù)據(jù)反演效果方面較其他方法有很大的優(yōu)勢(shì)。 本文首先對(duì)已知模型進(jìn)行數(shù)值模擬�；跀�(shù)值模擬計(jì)算所得結(jié)果,提取相關(guān)波場(chǎng)快照,初步研究超聲波在混凝土結(jié)構(gòu)中的傳播規(guī)律。從波場(chǎng)快照中可以得出,超聲波在設(shè)置有不同地質(zhì)隱患的混凝土介質(zhì)中顯現(xiàn)出明顯的傳播差異。其次本文又通過(guò)數(shù)值模擬來(lái)研究觀測(cè)系統(tǒng)對(duì)超聲波CT成像分辨率的影響,在設(shè)置相似的數(shù)值模擬模型、布置不同的觀測(cè)系統(tǒng)的基礎(chǔ)上,通過(guò)對(duì)比CT圖得出適合混凝土無(wú)損檢測(cè)的最佳觀測(cè)系統(tǒng),研究得知實(shí)測(cè)階段盡量采用多種觀測(cè)系統(tǒng)相互比較對(duì)比、相互印證得出結(jié)論。文中做了超聲波CT探查混凝土中夾層、空洞缺陷的數(shù)值模擬研究,得到超聲CT圖其收斂性較好,較清晰地反映出異常區(qū)的位置和尺寸。最后應(yīng)用數(shù)值模擬和物理模型試驗(yàn)相結(jié)合的方法,相互解釋相互指導(dǎo),結(jié)果表明超聲CT在實(shí)測(cè)階段可行性較高且具有良好的分辨率。 最后論文也指出了超聲CT在混凝土無(wú)損檢測(cè)方面存在的不足及今后的研究方向,文中所做的物理模型因其尺寸較小且所設(shè)置的介質(zhì)隱患種類較少,因而檢測(cè)效果雖好但不具有一定代表性。實(shí)際工程中混凝土結(jié)構(gòu)復(fù)雜,而且體型較大,其實(shí)際探測(cè)效果還有待于進(jìn)一步的實(shí)驗(yàn)研究。
[Abstract]:Due to the improper construction and external force, and the influence of the properties of the building materials, the concrete structure causes the medium hidden danger of the internal structure. The medium hidden danger in the concrete structure mainly includes honeycomb cavity, crack and local uncompactness. Because of these defects, Because the concrete structure is not complete, the compressive and tensile strength and durability of the concrete structure are seriously reduced. Therefore, it is necessary to carry out the rapid detection of concrete members in the engineering site. It is of great significance to ensure the safety of engineering construction. At present, the methods of nondestructive testing of concrete mainly include rebound method, impact echo method and radar method. These methods have their own disadvantages in the detection process, and are limited by the detection of concrete surface quality. It can not reflect the internal condition of concrete medium, the instrument is expensive and influenced by the steel bar, the field detection is difficult to spread out and the resolution of the medium hidden trouble is low. Ultrasonic testing can effectively solve these problems. Because of its strong penetration, high resolution, simple detection equipment and easy to operate, this kind of method has a great advantage over other methods in detecting cost and the effect of data retrieval in the later stage. In this paper, first of all, the known model is numerically simulated. Based on the results of numerical simulation, the relevant wave field snapshot is extracted, and the propagation law of ultrasonic wave in concrete structure is studied preliminarily. It can be obtained from the wave field snapshot. There are obvious differences in the propagation of ultrasonic wave in concrete medium with different geological hidden dangers. Secondly, the influence of observation system on the resolution of ultrasonic CT imaging is studied by numerical simulation, and a similar numerical simulation model is set up. Based on the arrangement of different observation systems, the best observation system suitable for nondestructive testing of concrete is obtained by comparing CT images. The study shows that various observation systems are used to compare and contrast each other in the stage of actual measurement as far as possible. The conclusion is drawn by mutual verification. The numerical simulation of ultrasonic CT to detect the sandwich and cavity defects in concrete is carried out, and the results show that the ultrasonic CT image has good convergence. The location and size of the abnormal area are clearly reflected. Finally, the method of numerical simulation and physical model test is used to explain and guide each other. The results show that the ultrasonic CT is feasible and has good resolution in the measured stage. Finally, the paper also points out the shortcomings of ultrasonic CT in nondestructive testing of concrete and the future research direction. The physical model made in this paper is smaller in size and less in the types of medium hidden dangers. Therefore, although the detection effect is good, it is not representative. The concrete structure is complex and the size is large in practical engineering, and the actual detection effect still needs further experimental study.
【學(xué)位授予單位】：安徽理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TU37;P631.5

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 楊奕,陳以方,付德永;超聲相控陣用于無(wú)損檢測(cè)的一種新方法[J];傳感器世界;2003年05期

2 趙明階;結(jié)構(gòu)砼損傷的超聲成像模型研究[J];重慶交通學(xué)院學(xué)報(bào);2001年S1期

3 楊風(fēng)暴,韓焱;金屬與非金屬粘接質(zhì)量的聲陣列檢測(cè)方法[J];測(cè)試技術(shù)學(xué)報(bào);2001年04期

4 趙永輝,吳健生;高頻雷達(dá)在混凝土無(wú)損檢測(cè)中的應(yīng)用及關(guān)鍵技術(shù)[J];CT理論與應(yīng)用研究;2000年02期

5 張建中,陳世軍,余大祥;最短路徑射線追蹤方法及其改進(jìn)[J];地球物理學(xué)進(jìn)展;2003年01期

6 張平松;劉盛東;李培根;;煤礦井巷間地質(zhì)構(gòu)造及其異常多波聯(lián)合探測(cè)技術(shù)與應(yīng)用[J];地球物理學(xué)進(jìn)展;2007年02期

7 劉勁松;劉福田;劉俊;郝天珧;;地震層析成像LSQR算法的并行化[J];地球物理學(xué)報(bào);2006年02期

8 楊奕,陳以方,曾陽(yáng);陣列超聲場(chǎng)的信號(hào)采集與處理系統(tǒng)[J];電子技術(shù)應(yīng)用;2003年04期

9 吳慧敏,吳新璇;建設(shè)工程無(wú)損檢測(cè)技術(shù)在我國(guó)的發(fā)展[J];工程質(zhì)量;1999年05期

10 張平松;郭立全;胡澤安;吳榮新;;混凝土結(jié)構(gòu)隱患快速勘探技術(shù)研究現(xiàn)狀與分析[J];地球物理學(xué)進(jìn)展;2014年06期

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