带包覆层圆管缺陷的非线性超声零频波检测方法研究  

A nonlinear ultrasonic zero-frequency wave detection method for coated pipe with flaws

作　　者：孙弋 赖泉青 邓明晰 Sun Yi;Lai Quanqing;Deng Mingxi(College of Aerospace Engineering,Chongqing University,Chongqing 400044,China)

机构地区：[1]重庆大学航空航天学院,重庆400044

出　　处：《仪器仪表学报》2025年第2期28-42,共15页Chinese Journal of Scientific Instrument

基　　金：国家自然科学基金(12134002)项目资助。

摘　　要：带包覆层圆管因绝缘、耐高压以及抗振动等优势被广泛地应用于石油、化工等领域。为保证带包覆层圆管在服役过程中的安全运行,有必要对其缺陷进行检测。然而,带包覆层圆管通常采用具有高声吸收衰减特性的高分子聚合物材料作为包覆层,从而使得传统的高频超声导波检测方法存在信噪比低等问题。另一方面,低频超声导波能传播足够长的距离,但存在检测盲区较大和分辨率较低等缺点。为此,提出一种基于非线性超声零频波的低声衰减、高灵敏度的带包覆层圆管缺陷检测方法。首先理论分析了非线性超声零频波沿圆管结构轴向传播时的生成机制,随后通过有限元仿真和实验验证探究了非线性超声零频波在自由圆管以及带包覆层圆管中的传播特性,最终在实验中利用非线性超声零频波成功地检测出带包覆层圆管内存在的切口状缺陷。结果表明:非线性超声零频波具有较低的声衰减特性,在线性基频超声波已完全衰减的情况下,非线性超声零频波仍然能够准确地识别出带包覆圆管内部存在的多个缺陷。该方法所述的非线性超声零频波因其载波频率为0而具有低声衰减的特性,能够用于带包覆层高声衰减圆管结构的无损检测。The coated pipe is widely used in the petroleum,the chemical industry,and other fields because of its advantages of insulation,high-pressure resistance and vibration resistance.To ensure the safe operation of the coated pipe during service,it is necessary to detect its flaws.However,the high polymer material with high sound absorption and attenuation characteristics is usually used as the coating layer of the coated pipe,which makes the traditional high-frequency ultrasonic guided wave detection methods have low signal-to-noise ratio problems.On the other hand,the low-frequency ultrasonic guided wave can travel a long enough distance,but it has the disadvantages of large detection blind areas and low resolution.For this reason,a high-sensitivity method based on nonlinear ultrasonic zero-frequency wave low attenuation is proposed to detect the flaws of coated pipe.Firstly,the generation mechanism of nonlinear ultrasonic zero-frequency wave propagating along the pipe structure was theoretically analyzed.Then,the propagation characteristics of nonlinear ultrasonic zero-frequency wave in free and coated pipe are investigated through finite element simulation and experimental verification.Finally,the notched defects in the coated pipe are successfully detected by using a nonlinear ultrasonic zerofrequency wave in the experiment.The results show that the nonlinear ultrasonic zero-frequency wave has a low attenuation characteristic,and the nonlinear ultrasonic zero-frequency wave can still accurately identify multiple defects in the coated pipe when the linear fundamental frequency ultrasonic wave has been completely attenuated.The nonlinear ultrasonic zero-frequency wave in the method has the characteristic of low attenuation because the carrier frequency is zero,and can be used in the nondestructive testing of the circular pipe structure with high attenuation of the coated layer.

关 键 词：带包覆层圆管 高声吸收衰减 缺陷 非线性超声 零频波 

分 类 号：TH89[机械工程—仪器科学与技术] O426.9[机械工程—精密仪器及机械]