李耿,张志芬,秦锐,都正尧,温广瑞,何卫锋.基于声发射信号的铝合金LSP弹塑性波传播规律探究[J].表面技术,2022,51(11):20-34.
LI Geng,ZHANG Zhi-fen,QI Rui,DU Zheng-yao,WEN Guang-rui,HE Wei-feng.Exploring the Law of Elastic-plastic Wave Propagation of Aluminum Alloy LSP based on Acoustic Emission Signal[J].Surface Technology,2022,51(11):20-34 |
| 基于声发射信号的铝合金LSP弹塑性波传播规律探究 |
| Exploring the Law of Elastic-plastic Wave Propagation of Aluminum Alloy LSP based on Acoustic Emission Signal |
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| DOI：10.16490/j.cnki.issn.1001-3660.2022.11.003 |
| 中文关键词: 激光冲击强化 声发射 弹塑性波 塑性变形 波形熵 时频分析 |
| 英文关键词:laser shock peening acoustic emission elastic-plastic wave plastic deformation waveform entropy time- frequency analysis |
| 基金项目:国家自然科学基金资助项目(52175433) |
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| Author | Institution |
| LI Geng | Xi'an Jiaotong University, Xi'an 710049, China |
| ZHANG Zhi-fen | Xi'an Jiaotong University, Xi'an 710049, China |
| QI Rui | Xi'an Jiaotong University, Xi'an 710049, China |
| DU Zheng-yao | Xi'an Jiaotong University, Xi'an 710049, China |
| WEN Guang-rui | Xi'an Jiaotong University, Xi'an 710049, China |
| HE Wei-feng | Xi'an Jiaotong University, Xi'an 710049, China;Air Force Engineering University, Xi'an 710038, China |
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| 中文摘要: |
| 目的 为提高激光冲击强化(LSP)的声发射(AE)监测精度，结合AE监测技术与LSP弹塑性波理论，探究LSP过程中弹塑性波传播规律。方法 首先，基于弹塑性波理论设计LSP试验，采用AE监测技术实时获取冲击信号，并测量冲击后铝合金7075的塑性变形程度。然后，基于AE信号的时域波形，提出包络欧式距离法，确定对加工质量敏感的感兴趣片段(FOI)。进一步基于FOI，结合实际加工条件，定义了新的累积AE波形熵特征。最后，基于AE信号的多模态和非平稳信息，定义瞬时峰值能量曲线(IPEC)，并进一步提取相关特征，从而探究弹塑性波传播规律、衡量传感器优劣。结果 仅包含弹性波的AE信号波形明显区别于弹塑性双波，塑性波传播速度明显落后于弹性波。包络欧式距离法确定的FOI能很好地定位弹塑性波。相较于AE波形熵，累积AE波形熵特征能很好地区分不同程度的弹塑性波。对比弹性波，塑性波主要集中在中低频段(200 kHz以下)。IPEC曲线精准确定31 kHz模态为塑性波的主要成分。进一步提取的峰值变化量 和峰值延迟时间 表明:相较于谐振传感器，宽频传感器对塑性波更加敏感。结论 所提方法和特征分别从时域和时频域上探究了弹塑性波的传播规律，所得的结论为规范和提高LSP的AE监测技术提供了理论支持与指导。 |
| 英文摘要: |
| In order to improve the acoustic emission (AE) monitoring accuracy of laser shock peening (LSP), combined with the AE monitoring technology and the elastic-plastic wave theory in the LSP field, based on the time domain and time-frequency domain information of the AE signal, the internal elastic-plastic wave propagation law of the aluminum alloy 7075 plate during the LSP process is explored, which provides a theoretical basis for the follow-up LSP monitoring research. Firstly, combined with the elastic-plastic wave theory, LSP experiments under different laser power densities are designed, and the AE piezoelectric sensing technology is used to obtain the impact signal in the processing process in real time, The PGI3D aspheric surface measuring instrument was used to measure the surface plastic deformation degree of the aluminum alloy 7075 plate after laser shock strengthening. Secondly, in order to facilitate the subsequent data analysis and processing, based on the time-domain waveform of the AE signal, an envelope Euclidean distance method is proposed to determine the Fragment of Interest (FOI) sensitive to the processing quality; further based on FOI, combined with actual processing conditions, a new cumulative AE waveform entropy feature is defined. Finally, according to the multi-modal and non-stationary characteristics of the AE signal, modal decomposition and wavelet time-frequency analysis are performed on the AE signal to define the instantaneous peak energy curve (IPEC), and further extract the characteristics of peak change and the peak delay time , so as to explore the propagation law of elastic-plastic waves and measure the advantages and disadvantages of different sensors. The experimental analysis results show that the time-domain waveform of the AE signal containing only elastic waves is obviously different from the AE signal of the elastic-plastic double wave, and the propagation speed of the plastic wave inside the plate is obviously behind that of the elastic wave. The segment of interest determined by the envelope Euclidean distance method based on the time-domain waveform of the AE signal can distinguish the elastic-plastic wave well. Compared with the original AE waveform entropy feature, the new accumulated AE waveform entropy feature defined in combination with the processing conditions can be very good. Different degrees of elastoplastic waves are well differentiated. Different from elastic waves, plastic waves in aluminum alloy 7075 plates are mainly concentrated in the middle and low frequency bands (below 200 kHz). The IPEC curve proposed based on AE time-frequency domain information can not only accurately determine the 31 kHz mode as the main component of plastic waves, At the same time, the peak variation and peak delay time extracted on the basis show that the broadband sensor is more sensitive to plastic waves than the resonant sensor. In this paper, for the first time, the multi-modal characteristics in the AE signal are combined with the shock wave theory in the LSP processing process, the methods and features proposed in this paper explore the propagation law of elastic-plastic waves from the time domain and time-frequency domain, respectively. The conclusions obtained provide theoretical support and guidance for standardizing and improving the AE monitoring technology of LSP. |
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