Adaptive ultrasonic inspection of complex-shaped structures: From data acquisition to imaging algorithms

Complex-shaped structures are common in engineering components and prone to internal defect formation or even failure during manufacturing and service. Non-destructive ultrasonic inspection is an effective method for evaluation of manufacturing quality and in-service safety but faces challenges in ultrasonic coupling, ultrasound transmission and detection, surface conformal scanning control, and complex ultrasound propagation behavior brought by shape complexity of the tested structure. This review summarizes and addresses the challenges in adaptive ultrasonic inspection of complex-shaped structures, and discusses current developments in methodologies for solving such problems from the aspects of ultrasonic data acquisition, structure modeling, and defect imaging. Finally, future prospects for ultrasonic imaging of complex-shaped structures are proposed, including methods for inspecting ultra-complex and irregular surfaces, the development of highly flexible two-dimensional arrayed ultrasonic transducers, and the enhancement of imaging algorithms by simultaneously accounting for the influence of both macro/micro morphology and acoustic properties of the tested structure.