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FOULING DETECTION IN FOOD VESSELS USING INTERDIGITAL LAMB WAVE TRANSDUCER

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Chinese Journal of Mechanical Engineering 2007年第1期20卷 111-114页

作者： jiao jingpin GE Haiyan WU Bin HE Cunfu College of Mechanical Engineenng and Applied Electronic Technology Beijing University of Technology Beijing 100022 China

Lamb waves are used to detect fouling in food vessels. The propagation of the Lamb waves in plates exhibits many modes and dispersion characteristics, which have great influence on fouling detection. The relative distribution of the in-plane and out-of-plane displacement of the mode across the thickness of the plate will determine the sensitivity of the mode to a particular loading condition. By considering the dispersion and multi-mode characteristics of guided waves, an interdigital polyvi- nylidene fluoride （PVDF） transducer is designed to realize the mode selection of gnided waves, and a single a0 mode is used for guided wave detection. Fouling detection experiments are conducted in the laboratory using epoxy adhesive on a thin plate. Using the interdigital PVDF transducer, three fouled areas are detected. Using one of the time-frequency analysis methods, the waveforms are further processed. This also demonstrates the validity of this method of fouling detection.

关键词： Lamb waves Interdigital transducer Fouling detection

Application of Nonlinear Lamb Wave Mixing Method for Residual Stress Measurement in Metal Plate

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Chinese Journal of Mechanical Engineering 2023年第1期36卷 211-223页

作者： jingpin jiao Li Li Xiang Gao Quan Cheng Cunfu He Bin Wu Faculty of Materials and Manufacturing Beijing University of TechnologyBeijing 100124China

Harmonic nonlinear ultrasound can offer high sensitivity for residual stress measurements;however,it cannot be used for local stress measurements at a point in space and exhibits nonlinear distortions in the experimental *** paper presents a feasibility study on the measurement of residual stress in a metal plate using a nonlinear Lamb wave-mixing *** resonant conditions for two Lamb waves to generate a mixing frequency wave are obtained via theoretical *** element simulations are performed to investigate the nonlinear interactions between the two Lamb *** show that two incident A0 waves interact in regions of material nonlinearity and generate a rightward S0 wave at the sum *** stress measurement experiments are conducted on steel plate specimens using the collinear Lamb wave-mixing *** setting different delays for two transmitters,the generated sum-frequency component at different spatial locations is *** results show that the spatial distribution of the amplitude of the sum-frequency component agrees well with the spatial distribution of the residual stress measured using *** proposed collinear Lamb wave-mixing method is effective for measuring the distribution of residual stress in metal plates.

关键词： Residual stress Lamb wave Collinear wave mixing Nondestructive testing Resonant conditions

Application of Uniform Experimental Design in Optimizing Excitation Parameters for Magnetic Frequency Mixing Measurements

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Chinese Journal of Mechanical Engineering 2020年第1期33卷 197-209页

作者： Yu Chang jingpin jiao Xiucheng Liu Guanghai Li Cunfu He Bin Wu College of Mechanical Engineering and Applied Electronics Technology Beijing University of TechnologyBeijing 100124China China Special Equipment Inspection and Research Institute Beijing 100013China

Excitation parameter preferences are key factors a ecting the performance of magnetic frequency mixing detection.A uniform experimental design method was used to analyze this *** fuzzy theory,a comprehensive model is established for evaluating the e ect of magnetic frequency mixing.A polynomial is selected as the regression function to express explicitly the correlation between the excitation parameters and the frequency-mixing e *** excitation parameters were then optimized using genetic *** frequency mixing experiments were conducted to measure the surface hardness of some ferromagnetic *** mixing is further enhanced under the optimal settings,resulting in an improvement in the measurement *** results of this study support the application of the magnetic frequency mixing technique in non-destructive testing.

关键词： Magnetic frequency mixing technology Excitation parameters Uniform experimental design Regression statistical method Surface hardness measurement

Excitation and Detection of Shear Horizontal Waves with Electromagnetic Acoustic Transducers for Nondestructive Testing of Plates

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Chinese Journal of Mechanical Engineering 2014年第2期27卷 428-436页

作者： MA Qingzeng jiao jingpin HU Ping ZHONG Xi WU Bin HE Cunfu Electric Power Research Institute of Guangdong Power Grid Corporation College of Mechanical Engineering and Applied Electronics Technology Beijing University of Technology

The fundamental shear horizontal（SH0） wave has several unique features that are attractive for long-range nondestructive testing（NDT）. By a careful design of the geometric configuration, electromagnetic acoustic transducers（EMATs） have the capability to generate a wide range of guided wave modes, such as Lamb waves and shear-horizontal（SH） waves in plates. However, the performance of EMATs is influenced by their parameters. To evaluate the performance of periodic permanent magnet（PPM） EMATs, a distributed-line-source model is developed to calculate the angular acoustic field cross-section in the far-field. Numerical analysis is conducted to investigate the performance of such EMATs with different geometric parameters, such as period and number of magnet arrays, and inner and outer coil widths. Such parameters have a great influence on the directivity of the generated SH0 waves that arises mainly in the amplitude and width of both main and side lobes. According to the numerical analysis, these parameters are optimized to obtain better directivity. Optimized PPM EMATs are designed and used for NDT of strip plates. Experimental results show that the lateral boundary of the strip plate has no perceivable influence on SHO-wave propagation, thus validating their used in NDT. The proposed model predicts the radiation pattern ofPPM EMATs, and can be used for their parameter optimization.

关键词： electromagnetic acoustic transducers shear-horizontal waves strip plate nondestructive testing

一种用于管道泄漏声定位的可调Q因子小波变换分析方法

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声学学报 2018年第3期43卷 355-363页

作者：王美刚焦敬品山西大学自动化系太原030013 北京工业大学机械工程与应用电子技术学院北京100124

针对泄漏声发射信号的非平稳随机特性,进行了泄漏声信号可调Q因子小波变换（Tunable Q-Factor Wavelet Transform,TQWT）的理论分析和实验研究。首先通过对典型泄漏声信号的TQWT分析,研究品质因子和分解尺度对泄漏声特征提取的影响。然... 详细信息

针对泄漏声发射信号的非平稳随机特性,进行了泄漏声信号可调Q因子小波变换（Tunable Q-Factor Wavelet Transform,TQWT）的理论分析和实验研究。首先通过对典型泄漏声信号的TQWT分析,研究品质因子和分解尺度对泄漏声特征提取的影响。然后根据峭度最大原则,优选出适合泄漏声信号分析的TQWT参数。在此基础上,提出了一种基于TQWT提取管道泄漏声特征分量的方法,并将提取的特征分量进行互相关分析用于管道泄漏定位。实验结果表明,利用该方法可以有效提取出泄漏声信号中的特征分量,从而更好实现泄漏定位,定位误差较小。该项研究工作为实际工程管道泄漏检测提供了可行的解决方案。

关键词：小波变换分析管道泄漏 Q因子可调声定位 Transform 声信号分析特征提取

用于缺陷定量的超声散射信号去相关分析及贝叶斯反演方法

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声学学报 2021年第2期46卷 281-291页

作者：李立焦敬品吴斌何存富北京工业大学材料与制造学部北京100124

针对结构中缺陷定量识别问题,建立了椭圆缺陷超声散射仿真模型,研究了缺陷偏转角度及尺寸对散射信号去相关特性的影响。结果表明,超声信号去相关系数矩阵与缺陷几何状态(如尺寸及角度)存在很大关联性,但并非线性相关。结合参数化有限元... 详细信息

针对结构中缺陷定量识别问题,建立了椭圆缺陷超声散射仿真模型,研究了缺陷偏转角度及尺寸对散射信号去相关特性的影响。结果表明,超声信号去相关系数矩阵与缺陷几何状态(如尺寸及角度)存在很大关联性,但并非线性相关。结合参数化有限元分析与贝叶斯理论,发展了一种基于超声散射信号去相关分析的缺陷反演方法,开展了缺陷反演数值仿真及检测实验。结果表明,发展的缺陷反演方法可以很好实现铝块与铝板缺陷位置及尺寸反演。其中铝块开口缺陷尺寸(深度)反演误差约为激励波长0.2倍,位置误差约为激励波长0.6倍;铝板圆形缺陷尺寸反演误差约为激励波长0.04倍,位置误差约为激励波长0.4倍。研究工作为结构中缺陷定量识别与评价做了有益探索。

关键词：相关系数矩阵超声散射非线性相关贝叶斯理论缺陷尺寸椭圆缺陷缺陷定量散射信号

基于虚拟聚焦的板结构兰姆波换能器阵列检测方法研究

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机械工程学报 2011年第8期47卷 12-20页

作者：焦敬品杨敬何存富吴斌北京工业大学机械工程与应用电子技术学院北京100124

针对板结构大范围无损检测问题,发展一种基于软件虚拟聚焦的兰姆波换能器阵列检测方法,即基于相控阵中等相位叠加原理,在无需相位控制硬件系统条件下,通过对换能器阵列接收数据进行软件处理,实现换能器阵列声束的指向聚焦。利用仿真数据... 详细信息

针对板结构大范围无损检测问题,发展一种基于软件虚拟聚焦的兰姆波换能器阵列检测方法,即基于相控阵中等相位叠加原理,在无需相位控制硬件系统条件下,通过对换能器阵列接收数据进行软件处理,实现换能器阵列声束的指向聚焦。利用仿真数据,研究阵列直径、阵元数量、声束数量等对虚拟聚焦成像周向分辨率和旁瓣噪声的影响,得出检测结果无明显旁瓣噪声所需要满足的条件为阵元间距应小于检测兰姆波的半波长。基于数值仿真处理结果,进行电磁声换能器阵列兰姆波检测试验研究。结果表明,在选择合适的阵列直径、阵元数量、声束数量的条件下,通过对换能器阵列检测信号进行虚拟聚焦处理,可以实现板结构任意方向特征体(如边界)的识别和缺陷检测。

关键词：阵列虚拟聚焦兰姆波声束指向聚焦电磁声换能器

厚度渐变结构介电性能测试用变间距叉指型相邻电容传感器设计

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机械工程学报 2017年第18期53卷 1-9页

作者：焦敬品李亮何存富吴斌北京工业大学机械工程与应用电子技术学院北京100124 北京工业大学北京市精密测控技术与仪器工程技术研究中心北京100124

针对厚度渐变高分子结构介电性能检测问题,设计一种变间距叉指型相邻电容传感器。研究不同叉指个数和极板覆盖率对等间距叉指相邻电容传感器信号强度和穿透深度的影响,确定了单对叉指单元的宽度范围;研究单对叉指单元参数对相邻电容传... 详细信息

针对厚度渐变高分子结构介电性能检测问题,设计一种变间距叉指型相邻电容传感器。研究不同叉指个数和极板覆盖率对等间距叉指相邻电容传感器信号强度和穿透深度的影响,确定了单对叉指单元的宽度范围;研究单对叉指单元参数对相邻电容传感器性能的影响,得到单对叉指单元传感器的穿透深度;根据待测结构厚度变化规律,对组成叉指传感器电极的单个叉指单元的宽度和间距进行了优化设计,设计出变间距叉指型相邻电容传感器。仿真和试验结果表明,变间距叉指型相邻电容传感器的信号强度和灵敏度优于等间距传感器,该传感器更适合渐变厚度结构材料的介电性能检测。

关键词：厚度渐变结构相邻电容传感器变间距叉指传感器穿透深度高分子材料

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基于迭代递推的供水管道多泄漏点声定位方法

振动与冲击 2020年第14期39卷 1-8页

作者：焦敬品任玉宝吴斌何存富北京工业大学机械工程与应用电子技术学院北京100124

针对多泄漏点产生的声发射信号及环境噪声对供水管道泄漏定位的影响,进行供水管道多泄漏点声定位方法研究。发展了一种基于迭代递推的供水管道多泄漏点声定位方法,研究迭代递推中品质因数阈值、信噪比阈值、相位偏移量的寻优区间和泄漏... 详细信息

针对多泄漏点产生的声发射信号及环境噪声对供水管道泄漏定位的影响,进行供水管道多泄漏点声定位方法研究。发展了一种基于迭代递推的供水管道多泄漏点声定位方法,研究迭代递推中品质因数阈值、信噪比阈值、相位偏移量的寻优区间和泄漏相关时频点的判定阈值等参数选择对泄漏定位效果的影响,并优选出适合的参数值。在此基础上,进行供水管道多漏点检测实验;结果表明,该方法可以实现管道上多个泄漏检测和定位,且定位误差小于1 m。研究工作为实际供水管道多泄漏点检测及定位提供了可行的解决方案。

关键词：供水管道声学检测迭代递推多泄漏点定位