Study on Propagation Characteristics of Refracted Longitudinal Waves in Carbon Fiber Composites

Based on the characteristics of non-destructive, efficient and accurate, the critical refraction longitudinal (LCR) wave method has high application value in the testing of composite materials. In this study, the finite element method was used to analyze the directivity of the refracted longitudinal wave in the carbon fibre reinforced plastics (CFRP) IIW test block. The relationship between the energy distribution of the ultrasonic sound field and the incident angle and frequency is studied. The influence of the anisotropy of CFRP in ultrasonic propagation was studied by comparing with isotropic materials. Using variable-angle wedges to excite LCR waves in different layered CFRP plates, the characteristics of the excitation angles of LCR waves in different directions in anisotropic materials are studied. This study provides guidance for future research on the detection of surface stress and structural health of carbon fiber composite materials using LCR waves.