Intralaminar Crack Detection for Carbon Fiber Reinforced Polymers Based on Laser-Line Thermography

Abstract

As Carbon fiber reinforced polymers (CFRP) are widely used in aerospace and marine engineering and other important fields, finding more efficient and rapid non-destructive testing (NDT) techniques to ensure the safety and reliability of CFRP composite materials has been the focus of research in the field of NDT. However, the current NDT techniques for carbon fiber reinforced polymer (CFRP) mainly detect defects that are parallel to the material surface, and there are few studies on defects that are perpendicular to the material surface, such as matrix cracking. In this paper, the laser-line thermography is compared with the lock-in thermography in time domain and spatial domain, and the effect of the main experimental parameters of laser thermography on the detection results is investigated. The results show that laser-line thermography can identify the characteristic size and geometric position of CFRP defects more accurately and significantly improve the imaging quality of defects. The analysis of the simulation results can conclude that the position corresponding to the temperature change peak under laser-line thermography is basically consistent with the boundary position of the defect, which can be used as a characteristic parameter for defect identification. When using laser-line thermography for material inspection, using a higher laser power and a shorter laser pulse duration can improve the imaging quality.