Dynamics-based Nondestructive Structural Health Monitoring Techniques

FBS, Inc. and Penn State, during Phase I of its Air Force Phase I STTR contract, demonstrated high sensitivity defect detection in both isotropic metallic and anisotropic composite structures using a novel ultrasonic modal analysis technique (UMAT). The resulting technology which is a merge of vibration modal analysis and the ultrasonic guided wave technique has shown great potential for providing a rapid, high sensitive, reliable, and cost effective nondestructive health monitoring solution for aircraft structures. The resonant frequencies and modal patterns in our work are strongly dependent on the ultrasonic loading functions. We are now looking to further develop the technology using novel time delay actuator designs that are capable of providing appropriate ultrasonic loading functions. An UMAT system will be developed. Phase II testing will fully demonstrate system effectiveness through extensive modeling and experimentation. BENEFIT: The proposed UMAT system will be capable of reliably inspecting a large structural areas using minimal number of sensors and minimal inspection time. The system will provide significant cost saving to the Air Force and private aviation sectors by avoiding the needs of disassembling aircraft structures due to the accessibility issues for defect detection. The system will be light-weight, easy to use, and battery operated. Thus the required services will be minimal and an operator would require only minimal technical skills. The defect detection sensitivities of the system will be superior due to the use of the appropriate ultrasonic loading functions. Thus the safety of military and private sector aircraft users will be increased. The UMAT concept will also be applicable to a variety of different industrial and mechanical structures.