Optimization of Defect Localization in Ultrasonic Images of CFRP Multidirectional Plates Based on Complex Geometry

Carbon fiber reinforced polymer (CFRP) composites are highly valued in aerospace for their superior strength and fatigue resistance. However, the structural complexity of CFRP components leads to inevitable internal defects during manufacturing, with complex geometry being a key factor hindering detection. This paper investigates the ultrasonic propagation characteristics in CFRP multidirectional plates with complex geometries via finite element simulations, focusing on the multifactor coupling effects in CFRP members. Acoustic tracing is conducted for the anisotropic and multilayered CFRP multidirectional plates. Through bottom reflection method and full-focus imaging inspection experiments, the propagation behaviors of ultrasonic waves in CFRP are systematically analyzed. Results reveal that the material’s multilayer structure, elastic anisotropy, and complex geometry significantly affect the imaging quality, defect localization accuracy, and defect distribution range in full-focus ultrasonic array inspection. The optimized algorithm achieves accurate detection of hole defects in complex-shaped CFRP multidirectional plates, reducing the imaging array performance indicator (API) value to 0.7 and the defect localization error to less than 0.3 mm. Keyword: CFRP components; complex geometries; non-destructive testing; acoustic tracing; full-focus imaging;