基于非线性超声技术损伤钢筋混凝土无损检测的适用性研究
发布时间:2018-04-19 22:19
本文选题:非线性超声技术 + 发射电压 ; 参考:《西安建筑科技大学学报(自然科学版)》2017年02期
【摘要】:以27个钢筋混凝土试件拉拔试验和1个立方体试块分级加载试验为基础,利用ZBL-U520非金属超声检测仪对试件进行无损检测,分析了接收器频率、发射电压对激发二次谐波的影响,以确定仪器最佳设置参数.在此基础上利用非线性超声技术,对不同荷载水平下的试件损伤进行了无损检测,研究了考虑锈蚀率以及荷载损伤的二次谐波和非线性系数变化关系,验证了非线性超声技术在钢筋混凝土无损检测中的适用性.结果表明:接收换能器频率为发射换能器2倍时,激发二次谐波效果更佳;对比不同发射电压(65 V、125 V、250 V、500 V、1 000 V)的频谱图,发现随着发射电压增加二次谐波幅值也增加,因此在仪器允许范围内要获得较为精确的非线性超声特征参数,选取发射电压1 000 V.随着试件锈蚀率和拉拔力增加,二次谐波幅值和非线性系数呈非线性变大趋势;配箍率和保护层厚度增加,试件二次谐波和非线性系数增加缓慢,反之二次谐波和非线性系数增加较快.试验分析表明:利用非线性超声技术对钢筋混凝土检测得到的非线性超声特征参数去表征试件损伤程度是较为准确和合适的.
[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.
【作者单位】: 哈尔滨工业大学结构工程灾变与控制教育部重点实验室;哈尔滨工业大学土木工程学院;哈尔滨工业大学(威海)土木系;
【基金】:国家自然科学基金资助项目(51678199)
【分类号】:TU528
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