| 摘要: |
| 为研究非线性超声非共线混频检测方法，证实2列入射基频波散射出混频波的可行性，基于混频测试理论，组建了测试系统，并讨论了最适合测试系统的激励幅值；在此基础上，针对含不同长度和不同角度预制裂纹的砂浆试件，进行了非共线混频法的检测试验，分析了超声非线性系数与裂纹长度和角度的关系.研究表明：非共线混频检测中的最佳激励幅值为100 V；随着裂纹长度和角度的增大，混频法非线性系数逐渐增大，且混频振幅也有类似趋势；为了验证非共线混频法的可靠性，将非共线混频法与高次谐波法的试验结果进行对比，得到了非共线混频法非线性系数对裂纹长度和角度的变化更敏感、相关趋势更显著的规律，证实了非共线混频法可用于混凝土等非均质材料的损伤检测. |
| 关键词: 裂纹 非线性超声 非共线混频 非线性系数 |
| DOI：10.3969/j.issn.1007-9629.2022.03.001 |
| 分类号:TU528.01 |
| 基金项目:江西省交通运输厅科技项目（2018Q0028，2019Q0027） |
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| Study on Ultrasonic Test of Mortar Specimens with Cracks Using Non-collinear Mixing Method |
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LIU Jianfeng1, WANG Kui1, PENG Aihong2, ZHAO Mingjie1
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1.Engineering Research Center of Diagnosis Technology and Instruments of Hydro-Construction， Chongqing Jiaotong University， Chongqing 400074， China;2.Jiangxi Transportation Engineering Group Co.， Ltd.， Nanchang 330000， China
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| Abstract: |
| Based on the mixing method theory， in order to study the nonlinear ultrasonic non-collinear mixing method， and to verify the feasibility of the two columns of incident fundamental waves scattering out the mixing wave， a test system was set up with discussing the most suitable excitation amplitude. On this basis， the non-collinear mixing method was carried out at the mortar test blocks with lengths and angles of prefabricated cracks. The relationship between the crack length， angle and the ultrasonic nonlinear coefficient was analyzed. As a result， 100 V is the best excitation amplitude in non-collinear mixing detection. The nonlinear coefficient of the mixing frequency gradually increases as the length and angle of the crack increasing. The amplitude of the mixing frequency has a similar trend. To verify the reliability of the non-collinear mixing method， the comparison with the test results of the higher harmonic ratios method shows that the nonlinear coefficient of the former is more sensitive to the change of the length and angle of the crack than the other one. Those proves that the non-collinear mixing method can be used for the damage detection of heterogeneous materials such as concrete. |
| Key words: crack nonlinear ultrasound non-collinear mixing nonlinear coefficient |
