Abstract: Aiming at the typical defects of Z-pin reinforced carbon fiber composite laminates in manufacturing, and based on the analysis of its effect on the temperature field, this paper studies the method of defect thermal feature extraction in Z-pin structure. The finite element method was used to analyze the relationship between different sizes of resin-rich region defects, different depths fracture of Z-pin, different angles of Z-pin, and detectable information parameters. Experimeutal tests were carried out to verify the detection of resin-rich region defects. The results show that the maximum temperature difference and maximum contrast increase with the increase of the area of the rich resin region, decrease with the increase of the Z-pin fracture depth, and increase with the increase of the Z-pin tilt angle, for which both the degree of reduction and promotion are nonlinear. The infrared thermal imaging experiment is consistent with the simulation results. The research results provide theoretical basis and technical support for infrared thermal imaging detection and evaluation of Z-pin reinforced composite laminate defects and damage.

Key words: Z-pin composite, infrared testing, simulation analysis, NDT, defect analysis