Acousto-Ultrasonic SHM/NDE Methods Toward Field Application

Acousto-ultrasonic nondestructive evaluation (NDE) and structural health monitoring (SHM) methods offers solutions in damage detection, material properties evaluation and more. These ultrasonic waves can propagate through solids and interact with structural features and discontinuities. In this thesis use of several acousto-ultrasonics NDE/SHM methods were explored to evaluate their sensing and detection capabilities toward damage detection field applications in nuclear and aerospace industries. For nuclear applications, passive sensing using piezoelectric sensors and acoustic emission (AE) techniques were explored on the spent fuel dry storage casks. Dry storage casks are used in the nuclear industry to transport or store spent nuclear fuel over long periods. NDE and SHM of these structures during their extended usage is highly desired to determine integrity and health of these components. Ultrasonic NDE/SHM potentially offers a solution as they can penetrate such structures and interact with the damage for timely detection if it presents. In this thesis ultrasonic guided waves excited by passive and active means are studied with the goal of determining the feasibility of such methods toward application on actual dry storage casks. Extensive experimental studies have been conducted on small, medium, and large-scale cask structures or similar. For aerospace applications, as aircraft technology progresses so does the number of composites used in aerospace construction. Hence, a means of nondestructive inspection is also desired. Within this thesis bond quality with various defects or contaminations were targeted and explored with both contact and non-contact type ultrasonic sensing methods. The contact methods are well established but require the use of additional coupling materials; while the non-contact means remove such a need and could lead to quick inspections but need further study to confirm their NDE/SHM capability. Results from both types were obtained and compared to the current standard techniques for evaluation and validation