Terahertz Imaging Detection of Delamination and Water Intrusion

We propose to demonstrate the feasibility of using time domain Terahertz (THz) measurements to locate and identify defects such as delaminations and water intrusion in advanced composite materials used in ground based radome panels, shelters and towers. We will investigate the ability of terahertz measurements, both with time domain and Fourier domain (i.e., spectroscopy) analysis, to detect defects of interest. These measurements will also be used to generate 2- and 3- dimensional high-resolution maps of the composite material structures. Additionally we will demonstrate the feasibility to detect other types of defects, such as metal intrusions, resin poor or rich areas and fluid contaminations (e.g., oil, fuel), in other materials such as aircraft composite structures. Water has comparatively higher absorption in the THz spectra, so the method should much more sensitive than microwave imaging to detect water intrusion. We will develop an algorithm requiring no, or only very minimal, human intervention to identify defects with accuracy and consistency. We will describe the design requirements of a prototype THz inspection system, to test Radomes panels, composite shelters and towers. In Phase II, we will deliver a prototype system providing accurate and consistent defect identification that is easy to handle by Radome climbers.