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学者姓名：刘增华
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摘要 ：
The identification and visualization of submillimeter microdefects have long been a critical focus within the realm of ultrasonic testing. The utilization of high-frequency signals is imperative due to the small acoustic interaction structure. An additional benefit of using lasers is their non-contact nature and ability to utilize multiple imaging modes, effectively reducing false or missed detections and enhancing credibility. This study proposes an advanced optimization algorithm for imaging and quantitative evaluation of submillimeter microdefects using laser ultrasonic full matrix capture (FMC) and total focusing method (TFM). The analysis of acoustic directionality under laser excitation and detection provides a foundation for mode selection. In preprocessing, the multi-scale principal component analysis (MSPCA) method is introduced to suppress coherent noise and blind spots. Moreover, phase coherence methods are implemented to further reduce mode artifacts, background noise, and residual surface acoustic wave (SAW). Additionally, multi-mode imaging and mode fusion are achieved using reflected longitudinal waves, reflected shear waves, converted longitudinal waves, and converted shear waves. Experiments were carried out on two different types of microdefects, namely side drilled holes (SDHs) and blind holes (BHs), resulting in high resolution TFM imaging with a minimum BH size of 0.3 mm. The outcomes demonstrate the efficacy of MSPCA in suppressing coherent noise, with further enhancement in imaging quality after phase coherence weighting. In addition, the -6 dB threshold of multi-mode images also provided the size information. This research is poised to contribute to the resolution of quality assessment challenges in powder metallurgy, welding, and additive manufacturing processes.
关键词 ：
Laser ultrasonic Laser ultrasonic Microdefect Microdefect Multi-mode imaging Multi-mode imaging Full matrix capture Full matrix capture Multi-scale principal component analysis Multi-scale principal component analysis
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| GB/T 7714 | Liu, Zenghua , Chen, Long , Zhu, Yanping et al. Multi-mode high resolution TFM imaging of microdefects based on laser ultrasonic full matrix capture [J]. | OPTICS AND LASER TECHNOLOGY , 2024 , 181 . |
| MLA | Liu, Zenghua et al. "Multi-mode high resolution TFM imaging of microdefects based on laser ultrasonic full matrix capture" . | OPTICS AND LASER TECHNOLOGY 181 (2024) . |
| APA | Liu, Zenghua , Chen, Long , Zhu, Yanping , Liu, Xiaoyu , He, Cunfu . Multi-mode high resolution TFM imaging of microdefects based on laser ultrasonic full matrix capture . | OPTICS AND LASER TECHNOLOGY , 2024 , 181 . |
| 导入链接 | NoteExpress RIS BibTex |
摘要 ：
Far-field laser technology has greatly promoted the progress of nondestructive ultrasonic imaging of bulk structures. However, under thermoelastic excitation, the body waves exhibit a relatively low signal-to-noise ratio, resulting in images with low resolution and contrast. Based on the motivation, this paper developed a frequency-domain phase weighted imaging method to improve the quality of laser ultrasonic defect imaging. Firstly, laser ultrasonic scanning was performed on the sample with artificial transverse hole defects. The cylindrical lens focused line source was used to improve the intensity of the body wave signals, and ensure that there was no damage on the material surface under high laser energies. Then, the frequency-domain phase shift migration (PSM) algorithm was used to perform multimode imaging of defects, achieving frequency-domain synthetic aperture focusing technique (F-SAFT) and total focused method (F-TFM) imaging based on full matrix capture. Furthermore, the phase circular statistical vector (PCSV) was proposed for weighted optimization, which improved the image quality, suppressed the background noise and multimode artifacts. Finally, the imaging quality of several algorithms were discussed. The results indicate that frequency-domain images were superior to time-domain results. After phase weighting, the imaging quality can be further improved, and the detection blind zone was significantly reduced. This work will contribute to the rapid and high-quality defect imaging of laser ultrasonic.
关键词 ：
Laser ultrasonic Laser ultrasonic Phase circular statistical vector Phase circular statistical vector Frequency-domain imaging Frequency-domain imaging Full matrix capture Full matrix capture Multimode imaging Multimode imaging
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| GB/T 7714 | Liu, Zenghua , Chen, Long , Zhu, Yanping et al. Laser ultrasonic frequency-domain imaging and phase weighted optimization based on full matrix capture [J]. | ULTRASONICS , 2024 , 141 . |
| MLA | Liu, Zenghua et al. "Laser ultrasonic frequency-domain imaging and phase weighted optimization based on full matrix capture" . | ULTRASONICS 141 (2024) . |
| APA | Liu, Zenghua , Chen, Long , Zhu, Yanping , Liu, Xiaoyu , Lu, Zhaojing , He, Cunfu . Laser ultrasonic frequency-domain imaging and phase weighted optimization based on full matrix capture . | ULTRASONICS , 2024 , 141 . |
| 导入链接 | NoteExpress RIS BibTex |
摘要 ：
本发明公开一种金属材料表面裂纹的宽频超声表面波定量评价方法。应用宽频超声表面波传感器对含有表面裂纹的金属材料进行表面波检测，通过检测获取宽频表面波信号，分析不同频率成分超声表面波与不同长度裂纹缺陷的作用规律，从宽频表面波信号中提取不同频率成分的超声特征参量，构建超声特征参量与金属材料表面裂纹缺陷信息的映射模型，使用超声特征参量对裂纹缺陷进行定量评价。本发明将宽频表面波评价方法应用于金属材料表面裂纹的定量评价中，利用宽频超声表面波中的不同频率成分超声特征参量对裂纹缺陷进行评价，提高了对金属材料表面裂纹缺陷定量评价的能力，在无损检测与结构健康监测领域具有极大的应用价值。
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| GB/T 7714 | 刘增华 , 郭彦弘 , 赵欣 et al. 一种金属材料表面裂纹缺陷的宽频超声表面波定量评价方法 : CN202310522897.3[P]. | 2023-05-10 . |
| MLA | 刘增华 et al. "一种金属材料表面裂纹缺陷的宽频超声表面波定量评价方法" : CN202310522897.3. | 2023-05-10 . |
| APA | 刘增华 , 郭彦弘 , 赵欣 , 耿浩 . 一种金属材料表面裂纹缺陷的宽频超声表面波定量评价方法 : CN202310522897.3. | 2023-05-10 . |
| 导入链接 | NoteExpress RIS BibTex |
摘要 ：
本发明公开了一种磁声发射信号时频域特征参数提取方法，通过CEEMDAN算法将信号分解为若干IMF，通过相关系数筛选含噪分量，对含噪分量进行小波包阈值降噪；对降噪分量与未处理分量进行Hilbert变换，综合得到信号时频分布，提取时频域特征参数表征不同热老化程度下的磁声发射信号特征。本发明解决了传统特征参数精度受限的问题，获取了更丰富的信息，用尽可能少的特征表示整个时频分布变化，提高了运算效率，能够做到对磁声发射信号进行准确、全面的分析，指导相关的无损检测技术现场的实际应用。
引用：
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| GB/T 7714 | 刘增华 , 闫旭婷 , 吴莎 . 一种磁声发射信号时频域特征参数提取方法 : CN202310197261.6[P]. | 2023-03-03 . |
| MLA | 刘增华 et al. "一种磁声发射信号时频域特征参数提取方法" : CN202310197261.6. | 2023-03-03 . |
| APA | 刘增华 , 闫旭婷 , 吴莎 . 一种磁声发射信号时频域特征参数提取方法 : CN202310197261.6. | 2023-03-03 . |
| 导入链接 | NoteExpress RIS BibTex |
摘要 ：
本发明公开了一种汽车发电机再制造质量评价方法，主要解决现阶段由于评价对象复杂、评价技术不成熟和评价标准不完善，而导致的汽车发电机再制造质量评价困难问题。本发明首先综合质量可靠性、技术、环境和经济四个方面构建多参数的汽车发电机再制造质量综合评价指标体系，其次提出最优传递矩阵改进的层次分析法和模糊综合评价法相结合的方法进行综合评价计算。该方法符合再制造工程实际，可以充分利用再制造过程数据，降低人为主观因素影响，得到的客观合理的评价结果有助于再制造方案的决策及优化。
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| GB/T 7714 | 龚裕 , 闫一鸣 , 刘增华 et al. 一种汽车发电机再制造质量评价方法 : CN202310163376.3[P]. | 2023-02-24 . |
| MLA | 龚裕 et al. "一种汽车发电机再制造质量评价方法" : CN202310163376.3. | 2023-02-24 . |
| APA | 龚裕 , 闫一鸣 , 刘增华 , 吴玉锋 , 梁秀兵 . 一种汽车发电机再制造质量评价方法 : CN202310163376.3. | 2023-02-24 . |
| 导入链接 | NoteExpress RIS BibTex |
摘要 ：
The boom is the key load-bearing component of the crane, and its health seriously threatens the service performance of the crane. In order to ensure the safe production of cranes, nondestructive testing (NDT) and structural health monitoring (SHM) of boom become more and more urgent and important. In this paper, the intelligent defect location algorithm based on helical guided waves is applied to the weld defect detection of U-shaped boom. Intelligent defect location algorithm is an imaging algorithm that combines ellipse imaging principle, evolutionary algorithm and K-means clustering algorithm. This paper verifies the effectiveness of this algorithm for weld defect location of U-shaped boom through experimental research. Firstly, the propagation regularity of helical guided waves in the U-shaped boom structure is studied. In addition, the elliptical imaging algorithm is used to image and analyze the weld defects in the U-shaped boom, and the location of the defects is preliminarily determined. The defect location analysis of weld defects is carried out by using the intelligent defect location algorithm. By comparing the imaging results of the two methods, it is found that the intelligent defect location algorithm has higher resolution and can effectively improve the defect location accuracy. This algorithm provides a tool for health monitoring of special-shaped structures based on guided waves.
关键词 ：
Clustering algorithm Clustering algorithm Helical guided waves Helical guided waves Structural health monitoring Structural health monitoring Evolutionary algorithm Evolutionary algorithm U-shaped crane boom U-shaped crane boom
引用：
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| GB/T 7714 | Lu, Zhaojing , Liu, Zenghua , Jiang, Wenshuo et al. Weld Defect Location Method of U-Shaped Crane Boom Based on Helical Guided Waves [J]. | EUROPEAN WORKSHOP ON STRUCTURAL HEALTH MONITORING (EWSHM 2022), VOL 3 , 2023 : 180-194 . |
| MLA | Lu, Zhaojing et al. "Weld Defect Location Method of U-Shaped Crane Boom Based on Helical Guided Waves" . | EUROPEAN WORKSHOP ON STRUCTURAL HEALTH MONITORING (EWSHM 2022), VOL 3 (2023) : 180-194 . |
| APA | Lu, Zhaojing , Liu, Zenghua , Jiang, Wenshuo , Chen, Honglei . Weld Defect Location Method of U-Shaped Crane Boom Based on Helical Guided Waves . | EUROPEAN WORKSHOP ON STRUCTURAL HEALTH MONITORING (EWSHM 2022), VOL 3 , 2023 , 180-194 . |
| 导入链接 | NoteExpress RIS BibTex |
摘要 ：
In this research, a three-dimensional (3D) transient finite element model based on a sequentially coupled thermal-mechanical analysis (SCTMA) is proposed to simulate the evolution of the temperature field and stress field as well as the cladding geometry of the Ni60A-25 % WC laser cladding composite coating. Based on the thermo-physical properties of Ni60A-25 % WC powder and the design of the double ellipsoidal heat source model, a 3D finite element model of double-layer laser cladding with two channels is established. The evolution of the temperature field and the residual stress field at different laser process parameters are investigated to evaluate the quality of the cladding layer. The impact of different laser cladding process parameters on the cladding dimensions is investigated. The dimensions of the simulated molten pool are analyzed by fitting a polynomial curve. The simulation results show that the laser power is proportional to the temperature, and the temperature growth rate of the coating is significantly higher than that of the substrate. The scanning speed is inversely proportional to the temperature. The maximum temperature of the cladding is 1.5 times the maximum temperature of the substrate. The temperature growth rate of the cladding layer is twice that of the substrate. Due to the asymmetry of the heat source in the multi-pass cladding process, the laser energy absorption rate is not the same on both sides of the melted layer. The double ellipsoidal heat source model has a larger diffusion range in the un-melted powder, resulting in asymmetry in the width direction of the cladding layer. The analysis of the residual stresses in the cladding layer shows that the residual compressive stresses in all paths increase with the increasing laser power. The normal x residual compressive stress in the coating and the maximum residual compressive stress occur at the end of the laser beam scan. The residual compressive stress in all paths decreases as the scanning speed increases. The results show that the dimensions of the molten pool are proportional to the laser power and inversely proportional to the scanning speed. The cladding geometry can be calculated with polynomial fitting equations at a selected laser power (500 W-2800 W) and scanning speed (1 mm/s-8 mm/s). The error analysis of the simulation and the experimental results can validate the proposed finite element simulation model. The error in the molten pool size is less than 20 % for the simulation and experimental results.
关键词 ：
Sequentially coupled thermal -mechanical Sequentially coupled thermal -mechanical Cladding geometry Cladding geometry Laser cladding Laser cladding Ni60A-25 %WC Ni60A-25 %WC Residual stress Residual stress
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| GB/T 7714 | Wu, Sha , Liu, Zenghua , Gong, Yu et al. Analysis of the sequentially coupled thermal-mechanical and cladding geometry of a Ni60A-25 %WC laser cladding composite coating [J]. | OPTICS AND LASER TECHNOLOGY , 2023 , 167 . |
| MLA | Wu, Sha et al. "Analysis of the sequentially coupled thermal-mechanical and cladding geometry of a Ni60A-25 %WC laser cladding composite coating" . | OPTICS AND LASER TECHNOLOGY 167 (2023) . |
| APA | Wu, Sha , Liu, Zenghua , Gong, Yu , Liang, Xiubing , Wu, Yufeng , Zhao, Xin . Analysis of the sequentially coupled thermal-mechanical and cladding geometry of a Ni60A-25 %WC laser cladding composite coating . | OPTICS AND LASER TECHNOLOGY , 2023 , 167 . |
| 导入链接 | NoteExpress RIS BibTex |
摘要 ：
In this research, to solve the problem of the ultrasonic guided wave inspection of a U-shaped boom, an improved periodic permanent magnet electromagnetic acoustic transducer (PPM EMAT) is proposed for defect detection for a U-shaped boom. The acoustic field distribution range of a traditional PPM EMAT is approximately +/- 20 degrees, and the energy distribution is relatively concentrated. By adjusting the tilt angle between adjacent magnets and coils of a traditional PPM EMAT, an improved PPM EMAT is proposed. The acoustic field distribution range of the improved PPM EMAT is approximately +/- 30 degrees, and the energy distribution in this range is relatively uniform. The simulation and experimental results show that the improved PPM EMAT has superior frequency response characteristics and acoustic field directivity, which is suitable for detecting large and complex structures. Furthermore, based on the traditional PPM EMAT and the improved PPM EMAT array, combined with the reconstruction algorithm for the probabilistic inspection of damage (RAPID), the damage locations of the double-hole defects of a U-shaped boom are studied. It is shown that the imaging results for defect location using the improved PPM EMATs are better than those found using the traditional PPM EMATs.
关键词 ：
PPM EMAT PPM EMAT reconstruction algorithm for the probabilistic inspection of damage reconstruction algorithm for the probabilistic inspection of damage U-shaped boom U-shaped boom damage imaging damage imaging guided waves guided waves
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| GB/T 7714 | Liu, Zenghua , Lu, Zhaojing , Jiang, Wenshuo et al. Damage imaging of a U-shaped boom using improved periodic permanent magnet electromagnetic acoustic transducers [J]. | NONDESTRUCTIVE TESTING AND EVALUATION , 2023 , 38 (6) : 977-1005 . |
| MLA | Liu, Zenghua et al. "Damage imaging of a U-shaped boom using improved periodic permanent magnet electromagnetic acoustic transducers" . | NONDESTRUCTIVE TESTING AND EVALUATION 38 . 6 (2023) : 977-1005 . |
| APA | Liu, Zenghua , Lu, Zhaojing , Jiang, Wenshuo , Guo, Yanhong , He, Cunfu . Damage imaging of a U-shaped boom using improved periodic permanent magnet electromagnetic acoustic transducers . | NONDESTRUCTIVE TESTING AND EVALUATION , 2023 , 38 (6) , 977-1005 . |
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摘要 ：
本发明公开了一种基于电磁超声导波技术的双层钢板分层缺陷无损检测方法，该方法利用电磁声传感器对双层钢板中的分层缺陷进行定量评估。与传统电磁超声导波检测方法不同，本发明将电磁声传感器安置在被测试样的端面，在端面激发导波，然后对超声信号进行时频分析，通过提取信号的幅值、相位、渡越时间等来实现对缺陷的定量评估。同时设计一款硬件扫查装置，该装置可携带传感器移动检测，提升检测速度。本发明将基于电磁超声导波技术的双层钢板分层缺陷无损检测方法应用于铁路和钢桥领域，改变了传感器的激发位置，提高试样的检测效率，为保障铁路、钢桥的安全运行具有深远意义。
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| GB/T 7714 | 刘增华 , 耿浩 , 唐国耀 et al. 一种基于电磁超声导波技术的双层钢板分层缺陷无损检测方法 : CN202210599056.8[P]. | 2022-05-30 . |
| MLA | 刘增华 et al. "一种基于电磁超声导波技术的双层钢板分层缺陷无损检测方法" : CN202210599056.8. | 2022-05-30 . |
| APA | 刘增华 , 耿浩 , 唐国耀 , 吴斌 , 何存富 . 一种基于电磁超声导波技术的双层钢板分层缺陷无损检测方法 : CN202210599056.8. | 2022-05-30 . |
| 导入链接 | NoteExpress RIS BibTex |
摘要 ：
本发明公开了一种海洋装备涂覆结构金属涂层损伤的宽频磁声多参量定量评估方法，应用宽频电磁声传感器，通过检测获取宽频磁声检测信号，提取各频率成分信号的电磁参量和声学参量，构建电磁参量、声学参量与金属涂层损伤的综合映射关系模型，实现涂覆结构金属涂层损伤电磁声多参量定量评估。本发明将基于电磁声传感器的宽频磁声多参量定量评估方法应用于海洋装备涂覆结构金属涂层损伤的定量评估中，增加了评估方法中的表征参量，提高了海洋装备涂覆结构金属涂层损伤定量评估的能力，对于保障海洋装备安全运行具有重要意义。
引用：
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| GB/T 7714 | 刘增华 , 郭彦弘 , 杨晴 et al. 一种海洋装备涂覆结构金属涂层损伤的宽频磁声多参量定量评估方法 : CN202210599264.8[P]. | 2022-05-30 . |
| MLA | 刘增华 et al. "一种海洋装备涂覆结构金属涂层损伤的宽频磁声多参量定量评估方法" : CN202210599264.8. | 2022-05-30 . |
| APA | 刘增华 , 郭彦弘 , 杨晴 , 吴斌 , 何存富 . 一种海洋装备涂覆结构金属涂层损伤的宽频磁声多参量定量评估方法 : CN202210599264.8. | 2022-05-30 . |
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