本文選題：非線性超聲技術(shù) + 發(fā)射電壓��； 參考：《西安建筑科技大學(xué)學(xué)報(自然科學(xué)版)》2017年02期

【摘要】：以27個鋼筋混凝土試件拉拔試驗和1個立方體試塊分級加載試驗為基礎(chǔ),利用ZBL-U520非金屬超聲檢測儀對試件進行無損檢測,分析了接收器頻率、發(fā)射電壓對激發(fā)二次諧波的影響,以確定儀器最佳設(shè)置參數(shù).在此基礎(chǔ)上利用非線性超聲技術(shù),對不同荷載水平下的試件損傷進行了無損檢測,研究了考慮銹蝕率以及荷載損傷的二次諧波和非線性系數(shù)變化關(guān)系,驗證了非線性超聲技術(shù)在鋼筋混凝土無損檢測中的適用性.結(jié)果表明:接收換能器頻率為發(fā)射換能器2倍時,激發(fā)二次諧波效果更佳;對比不同發(fā)射電壓(65 V、125 V、250 V、500 V、1 000 V)的頻譜圖,發(fā)現(xiàn)隨著發(fā)射電壓增加二次諧波幅值也增加,因此在儀器允許范圍內(nèi)要獲得較為精確的非線性超聲特征參數(shù),選取發(fā)射電壓1 000 V.隨著試件銹蝕率和拉拔力增加,二次諧波幅值和非線性系數(shù)呈非線性變大趨勢;配箍率和保護層厚度增加,試件二次諧波和非線性系數(shù)增加緩慢,反之二次諧波和非線性系數(shù)增加較快.試驗分析表明:利用非線性超聲技術(shù)對鋼筋混凝土檢測得到的非線性超聲特征參數(shù)去表征試件損傷程度是較為準(zhǔn)確和合適的.
[Abstract]:Based on the drawing test of 27 reinforced concrete specimens and the hierarchical loading test of one cube specimen, the nondestructive testing of the specimen was carried out by using the ZBL-U520 nonmetallic ultrasonic detector. The effects of receiver frequency and emission voltage on the excitation of second harmonic were analyzed. To determine the best setting parameters of the instrument. On the basis of this, the damage of specimens under different load levels is detected by using nonlinear ultrasonic technique. The relationship between the second harmonic and nonlinear coefficients considering corrosion rate and load damage is studied. The applicability of nonlinear ultrasonic technique in nondestructive testing of reinforced concrete is verified. The results show that when the frequency of the receiving transducer is 2 times that of the emission transducer, the effect of second harmonic excitation is better, and the second harmonic amplitude increases with the increase of the emission voltage, compared with the spectral diagram of different emission voltages of 65V / 125V / 125V / 25V / 250V / 500V ~ (1 000 V). Therefore, in order to obtain more accurate nonlinear ultrasonic characteristic parameters within the allowable range of the instrument, the emission voltage should be selected at 1 000 V. With the increase of corrosion rate and drawing force of the specimen, the amplitude of second harmonic and the nonlinear coefficient of the specimen show a nonlinear trend, while the ratio of hoop and the thickness of the protective layer increase slowly, and the second harmonic and nonlinear coefficient of the specimen increase slowly with the increase of corrosion rate and drawing force of the specimen. On the contrary, the second harmonic and nonlinear coefficients increase rapidly. The experimental results show that it is more accurate and appropriate to use the nonlinear ultrasonic characteristic parameters of reinforced concrete to characterize the damage degree of the specimens.
【作者單位】： 哈爾濱工業(yè)大學(xué)結(jié)構(gòu)工程災(zāi)變與控制教育部重點實驗室;哈爾濱工業(yè)大學(xué)土木工程學(xué)院;哈爾濱工業(yè)大學(xué)(威海)土木系;
【基金】：國家自然科學(xué)基金資助項目(51678199)
【分類號】：TU528

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