Array ultrasonic total-focus imaging for advanced resin matrix composite fiber wrinkle defect arrays

Advanced resin matrix composites were widely used in aerospace applications because of light weight and high strength. Fiber wrinkle defects were one of the defects in advanced resin matrix composites, which were inefficiently detected by conventional ultrasonic inspection, while the array ultrasound total-focus imaging detection technique relies on accurate acoustic propagation delay. To address the problem of difficult acoustic delay calculation due to anisotropy and multilayer refractive interfaces in advanced resin matrix composites, ray tracing method based on the Viterbi search algorithm was proposed for calculating the time delay of array ultrasonic total focus imaging inspection. The results of the array ultrasonic full-focus imaging inspection experiments on 5.92 mm thick multidirectional carbon fiber composite laminates show that the use of the ray tracing method to calculate the delay time allows the collected full-matrix signals to be accurately and coherently superimposed, effectively detecting the fiber winkle defects in multidirectional carbon fiber composite laminates.