Development of Microwave Interferometry Nondestructive Testing Solution for Complex Materials

Abstract

Application of engineered ceramic materials in high temperature environments of advanced propulsion systems in high performance aircraft; structural demands in ceramic-composite armor; application of high density polyethylene in piping, and reinforced rubber in nuclear power service; and fiber reinforced resin overwraps for piping, all present demanding nondestructive testing challenges. A new technology, Evisive Scan™, has been recently developed that allows condition monitoring in these challenging materials. The internationally patented Evisive Scan™ method is based on microwave interferometry. It utilizes microwaves to interrogate dielectric materials, including material with complex internal structure. The microwaves are reflected at areas of changing dielectric constant. The reflected energy and the interrogating beam are combined to form an interference pattern which is measured in the transceiver as a signal voltage. The method requires access to only one surface, does not require contact or a coupling medium. The signal voltage is sampled at many positions in the inspection area. This point cloud is displayed as an Evisive Scan™ image, which presents volumetric detail of the inspected part. This data is rich with information which is processed in near real time for advanced analysis. The technology has been successfully applied to Ceramic Matrix Composites where it is used to measure density and porosity and identify manufacturing defects. The technology has been demonstrated to be applicable to ceramic composite armor made of monolithic ceramic tiles in complex, multilayer, dielectric structures. The technology is being used to detect manufacturing defects in composite resin structures. The technology has been successfully demonstrated on fiber reinforced resin pipe overwraps, and the technology has been used for condition monitoring of reinforced rubber flexible couplings in nuclear power plants. The nuclear power plant application is performed under a fully qualified, US nuclear quality assurance 10CFR50 App B and NQA-1 compliant program. Examples of these applications are presented, with explanation of the operating principles of the technology and illustrations of the individual applications. Work included in the report is supported by the US Air Force Research Laboratory, US Army Tank-Automotive Research, Development and Engineering Center (TARDEC), US Army Research Laboratory and US Air Force Research Laboratory. Evisive would like to acknowledge project participation and support by Argonne National Laboratory, and Saudi Aramco.