Research on ultrasound propagation characteristics and quantitative evaluation of sub-millimeter foreign bodies in CFRP based on finite element simulation

Abstract

To address the critical issue of sub-millimeter Polytetrafluoroethylene (PTFE) foreign body inclusions inadvertently introduced during the manufacturing of Carbon Fiber Reinforced Polymer (CFRP), this study investigates the underlying detection mechanisms and quantitative evaluation methods using ultrasonic testing technology. A finite element simulation model of the CFRP-PTFE system was developed in COMSOL Multiphysics to conduct an in-depth analysis of ultrasonic wave propagation in multilayered anisotropic media and the mechanisms of interaction with sub-millimeter defects. The research examines the influence of defect size (ranging from 3 mm to 12 mm and spatial positioning on the amplitude and time-domain characteristics of ultrasonic echo signals. The results demonstrate that while the ultrasonic signal amplitude correlates positively with defect size, the growth trend significantly diminishes once the defect diameter exceeds 6 mm due to constraints imposed by the transducer crystal dimensions. This study elucidates the ultrasonic response characteristics of sub-millimeter inclusions, providing an efficient and reliable numerical simulation and experimental framework for the precise identification and quantitative assessment of microscopic foreign bodies within CFRP structures.