SUBJECT: Ph.D. Proposal Presentation
BY: Peter McKeon
TIME: Thursday, December 12, 2013, 3:00 p.m.
PLACE: Georgia Tech Lorraine, 113
TITLE: Ultrasonic Guided Waves to Monitor Anisotropic Mediums: Application to a High Pressure Composite Tank
COMMITTEE: Dr. Nico F. Declercq, Chair (ME)
Dr. Slah Yaacoubi (Inst. de Soudure)
Dr. Yves Berthelot (ME)
Dr. Laurence Jacobs (CEE)
Dr. Jennifer Michaels (ECE)
Dr. Laurent Capalungo (ME)
Dr. Salah Ramadan (Inst. de Soudure)


Ultrasonic guided waves (UGW) in free plates have been used in non-destructive testing for over 50 years. However, due to their dispersive and multi-modal nature, data analysis is very complicated, and becomes increasingly complex when the medium in question is an anisotropic multi-layer composite. Whereas analytical descriptions are readily available for mono-layer isotropic materials, numerical methods, such as FEM, are the clear choice for investigating more complicated materials. Furthermore, FEM can predict guided waves' interaction with damage of an arbitrary size and nature. This thesis will contain the efforts to numerically simulate the interaction between guided waves and damage in multi-layer, anisotropic plates in non-planar, plate-like structures for the purpose of structural health monitoring. These numerical calculations will be verified with experiments on samples supplied by our industrial partner, l'Institut de Soudure [Welding Institute]. The scope of the project includes calculating the directionally dependent dispersion curves, identifying the most efficient excitation method for improving the defect detection sensitivity, and determining a method of interpreting resulting waveforms that is useful in a real-world application to avoid false alarms. The ability to identify and localize damage in a cylindrical tank comprised of two diff erent anisotropic layers, and a third isotropic layer is used as a representative case.