摘要
激光冲击强化(LSP)作为一种新型的激光表面处理技术已应用于航空发动机、机匣等关键部件的强化延寿处理,确保LSP加工质量的一致性及稳定性对上述航空装备的长寿命服役具有重要意义。然而,在高能瞬态LSP过程中,保护层容易发生烧蚀破损,极大地限制了LSP的工业应用。因此,通过分析激光诱导等离子体光谱信号,提出了一种基于ReliefF特征权重融合的LSP保护层烧损实时检测方法。以4 mm厚的7075铝合金为LSP靶材,以黑胶带为LSP保护层。首先,利用长波段范围的Ocean Optics-HR4000光谱仪和高分辨率的Princeton SP2750光谱仪同步采集LSP瞬态过程中产生的等离子体光谱信息;其次,根据Princeton SP2750光谱仪采集的高精度光谱信号,分别选取波长为394.40和396.15 nm的AlⅠ谱线以及波长为393.36和396.80 nm的FeⅠ谱线,提取其峰值强度与Stark展宽特征,然后结合ReliefF特征重要度筛选出对保护层烧损状态更加敏感的两条AlⅠ谱线,并且定性分析了AlⅠ谱线的峰值强度和Stark展宽对保护层烧损状态的敏感程度和瞬态变化规律;再次,基于ReliefF算法构造了一种融合多谱线特征信息的特征参数I-FWHM(Intensity-FWHM),然后基于特征类间距离,定量评估了各特征对三类烧损状态的区分能力;最后,结合阈值分割法实现了LSP保护层烧损实时检测。实验结果表明,峰值强度对于区分正常状态与轻微破损状态的能力很差,而对于区分轻微破损与完全破损的能力很强;Stark展宽对于区分正常状态与轻微破损状态的能力远优于强度,而对于区分轻微破损与完全破损的能力相对较弱。I-FWHM融合了上述单一特征的优点,能同时较好地区分三类烧损状态,因此对于LSP过程中保护层烧损状态的实时检测具有更强的抗干扰能力和更高的鲁棒性。
As a new laser surface treatment technology,laser shock peening(LSP)has been applied to strengthen and prolong the life of critical components such as the aero-engine and gearbox.Ensuring the consistency and stability of LSP processing quality is of great significance to the long service life of the aviation mentioned above equipment.However,the protective coating is easily ablated and damaged in the high-energy transient LSP process,limiting the industrial application of LSP significantly.Therefore,this paper proposed a real-time detection method for protective coating damage of LSP based on ReliefF feature weight fusion by analyzing laser-induced plasma spectrum signal.The 7075 aluminum alloy with a thickness of 4 mm was used as an LSP target,and the black tape was used as the protective coating.Firstly,the Ocean Optics-HR4000 spectrometer with a wide wavelength range and Princeton SP2750 spectrometer with a high resolution was used to synchronously collect the plasma spectra produced in the LSP transient process.Secondly,according to the spectral signals with a high resolution collected by the Princeton SP2750 spectrometer,the peak intensities and Stark-FWHMs of AlⅠspectra at 394.40 and 396.15 nm and that of FeⅠspectra at 393.36 and 396.80 nm were extracted,then,combined with the feature importance obtained by the ReliefF algorithm to screen out two AlⅠspectra that were more sensitive to the damage states of the protective coating,andqualitatively analyzedthe sensitivity and the law of transient variation for intensity and Stark-FWHM of AlⅠspectra to the damage states of the protective coating.Furthermore,a feature named intensity-FWHM(I-FWHM)fusing the information of multiple spectral emission lines was constructed using the ReliefF algorithm,and then,the ability of each feature to distinguish the three kinds of damage states was quantitatively evaluated based on the distance between classes.Finally,combined with the threshold segmentation method,real-time detection of LSP protection layer damage was realized.The experimental results show that the intensity is very poor in distinguishing between normal state and slight damage but very strong in distinguishing between slight damage and complete damage.The Stark-FWHM is far better than intensity in distinguishing between the normal state and slight damage,but the abilityis relatively weak in distinguishing between slight and complete damage.The I-FWHM combines the advantages of the above single feature and can better distinguish the three types of damage states simultaneously.Therefore,I-FWHM has stronger anti-interference ability and higher robustness for the real-time detection of protective coating damage state in the LSP process.
作者
张志芬
刘子岷
秦锐
李耿
温广瑞
何卫锋
ZHANG Zhi-fen;LIU Zi-min;QIN Rui;LI Geng;WEN Guang-rui;HE Wei-feng(Institute of Aero-Engine,School of Mechanical Engineering,Xi'an Jiaotong University,Xi'an 710049,China;School of Aeronautical Engineering,Air Force Engineering University,Xi'an 710038,China)
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2023年第8期2437-2445,共9页
Spectroscopy and Spectral Analysis
基金
国家自然科学基金项目(52175433)
国家重点研发计划项目(2020YFB1710002)资助。
