Inspection of defects in composite structures using long pulse thermography and shearography
Yanjie Wei,
Yao Xiao,
Xiaohui Gu,
Jianying Ren,
Yu Zhang,
Dongsheng Zhang,
Yanhong Chen,
Haiyan Li,
Shaohua Li
Affiliations
Yanjie Wei
Department of Engineering Mechanics, Shijiazhuang Tiedao University, Shijiazhuang, 050043, China; Hebei Research Center of the Basic Discipline Engineering Mechanics, Shijiazhuang Tiedao University, Shijiazhuang, 050043, China; State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures, Shijiazhuang Tiedao University, Shijiazhuang, 050043, China; Hebei Key Laboratory of Mechanics of Intelligent Materials and Structures, Shijiazhuang Tiedao University, Shijiazhuang, 050043, China; Corresponding author. Department of Engineering Mechanics, Shijiazhuang Tiedao University, China.
Yao Xiao
Department of Engineering Mechanics, Shijiazhuang Tiedao University, Shijiazhuang, 050043, China
Xiaohui Gu
State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures, Shijiazhuang Tiedao University, Shijiazhuang, 050043, China
Jianying Ren
Department of Engineering Mechanics, Shijiazhuang Tiedao University, Shijiazhuang, 050043, China; Hebei Research Center of the Basic Discipline Engineering Mechanics, Shijiazhuang Tiedao University, Shijiazhuang, 050043, China
Yu Zhang
Department of Engineering Mechanics, Shijiazhuang Tiedao University, Shijiazhuang, 050043, China; Hebei Research Center of the Basic Discipline Engineering Mechanics, Shijiazhuang Tiedao University, Shijiazhuang, 050043, China
Dongsheng Zhang
Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, School of Mechanics and Engineering Science, Shanghai University, Shanghai, 200444, China
Yanhong Chen
CRCC Tangshan Co., Ltd., Tangshan, Hebei, China
Haiyan Li
Department of Engineering Mechanics, Shijiazhuang Tiedao University, Shijiazhuang, 050043, China; Hebei Research Center of the Basic Discipline Engineering Mechanics, Shijiazhuang Tiedao University, Shijiazhuang, 050043, China; Hebei Key Laboratory of Mechanics of Intelligent Materials and Structures, Shijiazhuang Tiedao University, Shijiazhuang, 050043, China
Shaohua Li
State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures, Shijiazhuang Tiedao University, Shijiazhuang, 050043, China
Long pulse thermography (LPT) and shearography have been developed as primary methods for detecting debonding or delamination defects in composites due to their full-field imaging, non-contact operation, and high detection efficiency. Both methods utilize halogen lamps as the excitation source for thermal loading. However, the defects detected by the two techniques differ due to their distinct inspection mechanisms. In this study, LPT and shearography are employed to evaluate internal damage in various composite structures. The experimental results demonstrate that LPT, when combined with thermal signal processing algorithms, can clearly detect debonding defects in rubber-to-metal bonded plates, whereas excessive adhesive defects can only be identified by shearography. Flat-bottom holes in the CFRP panel can only be detected by LPT, and shearography is particularly effective for detecting composite materials with a metal skin. For the quantitative measurement of defect sizes, the average errors of the rubber-to-metal bonded plate and CFRP panel using LPT are 4.9 % and 2.2 %, respectively, whereas the average errors of the rubber-to-metal bonded plate and aluminum honeycomb panel using shearography are 15.12 % and 95.4 %, respectively. This indicates that LPT is superior to shearography in quantitatively measuring defect sizes. These two nondestructive testing methods, based on different principles, each have their own advantages and disadvantages. Employing a multi-modal inspection method can leverage their complementary advantages, preventing misdetection and leakage of internal defects in composites.
