Glass fiber reinforced polymer terahertz feature enhancement and defect imaging based on continuous wavelet transform
-
摘要: 玻璃纤维增强树脂复合材料(Glass fiber reinforced polymer,GFRP)因其耐腐蚀、强度高等优点被广泛应用于航空航天、运输等领域,但在其制作过程中存在分层、气泡等缺陷,故需对其进行无损检测。本文针对不同位置的GFRP脱粘缺陷太赫兹无损检测信号特征微弱的问题进行分析与研究,提出了利用连续小波变换(Continue wavelet transform,CWT)对太赫兹特征进行增强的方法,并通过计算图像对比度客观评价连续小波变换后得到的太赫兹图像。最终选择gaus2小波基函数,对变换后的信号进行缺陷成像,其峰值较原来增强了4.5倍,连续小波变换处理后的太赫兹缺陷成像的图像对比度提升了1.3倍,最终实现了6 mm GFRP 5 mm位置处50 µm脱粘缺陷的识别。
-
关键词:
- 玻璃纤维增强树脂复合材料 /
- 太赫兹无损检测 /
- 连续小波变换 /
- 信号增强 /
- 缺陷成像
Abstract: Glass fiber reinforced polymer (GFRP) are widely applied in aerospace, transportation, etc., due to the advantages of corrosion resistance and high strength. However, defects such as delamination and bubbles formed in manufacturing call for non-destructive testing of such materials. This paper analyzed and addressed the drawback that the signal characteristics of debonding defects of GFRP with different depths are unobvious and put forward the continuous wavelet transform to enhance the terahertz feature methodology (CWT). Accordingly, the terahertz image obtained after continuous wavelet transform was objectively evaluated by calculating the image contrast. The gaus2 wavelet basis function was selected to perform defect imaging on the transformed signal. The peak value is increased by 4.5 times compared with the original, the image contrast of the terahertz defect imaging after continuous wavelet transform is increased by 1.3 times. Finally, the identification of the 50 μm debonding defect at the 5 mm position of the 6 mm GFRP is realized. -
表 1 缺陷信息
Table 1. Defect information
Defect type Defect
depth/mmDefect
thickness/mmUpper Delamination 2.0 0.30 Debonded 3.0 0.05 Lower Delamination 3.0 0.30 Debonded 5.0 0.05 表 2 THz缺陷成像图像对比度
Table 2. Image contrast of THz defect imaging map
Upper Lower Original image 11.543 13.713 Gaus2 image 15.073 18.081 -
[1] WANG Q, LI X Y, CHANG T Y, et al. Nondestructive imaging of hidden defects in aircraft sandwich composites using terahertz time-domain spectroscopy[J]. Infrared Physics and Technology,2019(97):326-340. [2] 李铁军, 孙跃, 邵桂芳, 等. 陶瓷基复合材料的太赫兹无损检测方法研究[J]. 激光与光电子学进展, 2018, 55(6):061101.LI Tiejun, SUN Yue, SHAO Guifang, et al. Research on terahertz nondestructive testing method of ceramic matrix composite[J]. Laser& Optoelectronics Progress,2018,55(6):061101(in Chinese). [3] 赖慧彬, 何明霞, 田甜, 等. 基于太赫兹光谱的固体片剂孔隙率研究[J]. 光学学报, 2018, 38(6):0630001. doi: 10.3788/AOS201838.0630001LAI Huibin, HE Mingxia, TIAN Tian, et al. Study on the porosity of solid tablets based on terahertz spectroscopy[J]. Acta Optica Sinica,2018,38(6):0630001(in Chinese). doi: 10.3788/AOS201838.0630001 [4] PALUMBO D, CAVALLO P, GALIETTI U. et al. An investigation of the stepped thermography technique for defects evaluation in GFRP materials[J]. NDT & E International,2019,102:254-263. [5] KUMA R P K, KUPPAN P. Online monitoring of delamination mechanisms in drilling of wants reinforced GFRP nanocomposites by acoustic emission[J]. Materials Today: Proceedings,2018,5(5):13036-13047. doi: 10.1016/j.matpr.2018.02.290 [6] CASTELLANO A, FRADDOSIO A, PICCIONI M D, et al. Quantitative analysis of QSI and LVI damage in GFRP unidirectionalcomposite laminates by a new ultrasonic approach[J]. Composites Part B: Engineering,2018,151:106-117. doi: 10.1016/j.compositesb.2018.06.003 [7] 胡金花, 李勇, 谭建国, 等. 玻璃纤维增强复合材料局部减薄损伤的微波无损定量检测[J]. 传感器与微系统, 2020, 39(3):113-116.HU Jinhua, LI Yong, TAN Jianguo, et al. Microwave non-destructive quantitative detection of localthinning damage of glass fiber reinforced composites[J]. Sensors and Microsystems,2020,39(3):113-116(in Chinese). [8] HOSOI A, YAMAGUCHI Y, JU Y, et al. Detection of delamination in GFRP and GFRP by microwaves with focusing mirror sensor[J]. Material Science Forum,2013,750:142-146. doi: 10.4028/www.scientific.net/MSF.750.142 [9] WANG P, LI Z, ZHOU L, et al. Microwave nondestructive detection and quantitative evaluation of kissing defects in GFRP laminates[J]. Composite Science and Technology,2018,162:117-122. doi: 10.1016/j.compscitech.2018.04.029 [10] 万陶磊, 常俊杰, 曾雪峰, 等. 基于经验模态分解和相关系数对玻璃纤维增强聚合物复合材料板的损伤识别及扫查成像[J]. 复合材料学报, 2020, 37(8):1921-1931.WAN Taolei, CHANG Junjie, ZENG Xuefeng, et al. Damage identification and scanning imaging of glass fiber reinforced polymer composite plates based on empiricalmode decomposition and correlation coefficient[J]. Acta Materiae Composite Sinica,2020,37(8):1921-1931(in Chinese). [11] 杨小林, 代永朝, 李艳红, 等. 红外热波技术在飞机复合材料损伤检测中的应用[J]. 无损检测, 2007, 29(4):200-202. doi: 10.3969/j.issn.1000-6656.2007.04.008YANG Xiaolin, DAI Yongchao, LI Yanhong, et al. Application of the thermalwave testing technology in composites of airplane[J]. Nondestructive Testing,2007,29(4):200-202(in Chinese). doi: 10.3969/j.issn.1000-6656.2007.04.008 [12] 张剑, 齐暑华. 红外热成像技术在复合材料无损检测中的应用现状[J]. 工程塑料应用, 2015, 43(11):122-126. doi: 10.3969/j.issn.1001-3539.2015.11.028ZHANG Jian, QI Shuhua. Application of infrared thermography in nonde-structive testing of composites[J]. Engineering Plastics Application,2015,43(11):122-126(in Chinese). doi: 10.3969/j.issn.1001-3539.2015.11.028 [13] 张丹丹, 任姣姣, 李丽娟, 等. 玻璃纤维蜂窝复合材料的太赫兹无损检测技术[J]. 光子学报, 2019, 48(2):0212002.ZHANG Dandan, REN Jiaojiao, LI Lijuan, et al. Terahertz nondestructive testing technology for glass fiber honeycomb composites[J]. Journal of Photonics,2019,48(2):0212002(in Chinese). [14] ZHANG J, SHI C, MA Y, et al. Spectroscopic study of terahertz reflection and transmission properties of carbon-fiber-reinforced plastic composites[J]. Optical Engineering,2015,54(5):054106.1-054106.7. [15] 任姣姣, 李丽娟, 张丹丹, 等. 太赫兹无损检测的多特征参数神经网络分析技术[J]. 光子学报, 2017, 46(4):0412002.REN Jiaojiao, LI Lijuan, ZHANG Dandan, et al. Multi-feature parameter neuralnetwork analysis technique based on terahertz nondestructive testing[J]. Journalof Photonics,2017,46(4):0412002(in Chinese). [16] XING L Y, CUI H L, SHI C, et al. Nondestructive examination of polymethacrylimide conposites structures with terahertz time-domain soectros copy method[J]. Polymer Testing,2017,57:141. doi: 10.1016/j.polymertesting.2016.11.022 [17] KAWASE K, SHIBUYA T, HAYASHI S, et al. THz imaging techniques for nondestructive inspections[J]. Comptes Rendus Physique,2010,11(7-8):510-518. doi: 10.1016/j.crhy.2010.04.003 [18] HAN D H, KANG L H, et al. Nondestructive evaluation of GFRP composite including multi-delamination using THz spectroscopy and imaging[J]. Composite Structures,2018,185:161-175. doi: 10.1016/j.compstruct.2017.11.012 [19] 廖晓玲, 刘延雷, 汪宏, 等. 基于THz波的玻璃纤维复合材料无损检测方法研究[J]. 玻璃钢/复合材料, 2015(9):35-38.LIAO Xiaoling, LIU Yanlei, WANG Hong, et al. Non-destructive inspection method for glass fiber composite based on THz wave[J]. Composites Science and Engineering,2015(9):35-38(in Chinese). [20] TU W, ZHONG S, SHEN Y, et al. Nondestructive testing of marine protective coatings using terahertz waves with stationary wavelet transform[J]. Ocean Engineering,2016,111:582-592. [21] 卢敏, 李小霞, 尚丽平, 等. 基于经验模态分解提高太赫兹频率分辨率的方法[J]. 光谱学与光谱分析, 2016, 36(9):2732-2735.LU Min, LI Xiaoxia, SHANG Liping, et al. Research on the method of improving Terahertz frequency resolution based on empirical mode decompositoon[J]. Spectroscopy and Spectral Analysis,2016,36(9):2732-2735(in Chinese). [22] 代冰, 王朋, 周宇, 等. 小波变换在太赫兹三维成像探测内部缺陷中的应用[J]. 物理学报, 2017, 66(8):088701. doi: 10.7498/aps.66.088701DAI Bing, WANG Peng, ZHOU Yu, et al. Wavelet transform in the application of three-dimensional terahertz imaging for internal defect detection[J]. Acta Physica Sinica,2017,66(8):088701(in Chinese). doi: 10.7498/aps.66.088701 [23] 蒋强, 俞跃, 叶凌伟, 等. 基于修正自相关算法的THz-TDS聚乙烯测厚反卷积算法[J]. 红外技术, 2020, 42(5):473-482. doi: 10.3724/SP.J.7101791850JIANG Qiang, YU Yue, YE Lingwei, et al. Deconvolution algorithm of THz-TDS polyethylene thickness measurement based on modified autocorrelation algorithm[J]. Infrared Technology,2020,42(5):473-482(in Chinese). doi: 10.3724/SP.J.7101791850 [24] 张瑾, 王洁, 沈雁, 等. 小波图像融合在太赫兹无损检测中的应用[J]. 光谱学与光谱分析, 2017, 37(12):3683-3688.ZHANG Jin, WANG Jie, SHEN Yan, et al. Application of wavelet image fusion in Terahertz nondestructive testing[J]. Spectroscopy and Spectral Analysis,2017,37(12):3683-3688(in Chinese). [25] KIM D H, RYU C H, PARK S H, et al. Nondestructive evaluation of hidden damages in glass fiber reinforced plastic by using the terahertz spectroscopy[J]. International Journal of Precision Engineering and Manufacturing-Green Technology,2017,4(2):211-219. doi: 10.1007/s40684-017-0026-x [26] RYU C H, PARK S H, KIM D H, et al. Nondestructive evaluation of hidden multi-delamination in a glass-fiber-reinforced plastic composite using terahertz spectroscopy[J]. Composite Structures,2016,156:338-347. doi: 10.1016/j.compstruct.2015.09.055