MAE Distinguished Professor Ajit Mal gave one of the keynote speeches at the ASME 46th Annual Quantitative Nondestructive Evaluation (QNDE) Conference, which was held July 14-18, 2019, at the Red Lion Hotel on the River, in Portland, Oregon.
The speech was titled “Ultrasonic NDE of Composite Structures”. His lecture was on the defection of hidden damage in composite aircraft and aerospace structures using guided ultrasonic waves.
Composite materials are being used increasingly in a variety of aircraft and aerospace structures due to their high strength to weight ratio. They are, however, susceptible to internal defects that can occur during manufacturing of the structural components or during service of the structure. Hidden defects, if undetected, may grow during service, become unstable and result in a catastrophic failure of the composite structure. Thus, composite structures require extensive periodic or continuous monitoring throughout the life of the structure to detect the initiation and growth of defects at an early stage of their occurrence. Ultrasonic methods offer a cost-effective method to achieve this goal. A good understanding of the highly complex characteristics of ultrasonic waves in composite structures is a perquisite to developing a reliable nondestructive inspection technology for composite structures. This talk presents an overview of the work carried out by the speaker and his associates on the characteristics of ultrasonic waves that can propagate in plate-like composite structural components using a combination of analytical, numerical and experimental methods. No attempt is made here to provide a comprehensive review of the NDE of composite structures.