Despite the rapid and significant growth in the use of composite and non-metallic components, fast and robust non-destructive testing of these materials is still an unfulfilled requirement. In particular, composite pipes are rapidly replacing metallic pipes in the oil and gas industry to combat corrosion. However, traditional non-destructive testing techniques cannot be employed for assessment of these components made of composite materials, due to the challenge of ultrasonic testing and other methods suitable for metallic components but not for composite materials. Thus, to bridge this gap, in this project, microwave imaging technology will be employed for volumetric inspection of cylindrical composite components and concentric pipes. The imaging technology is fast and reliable, and it can be employed for inspection of a vast range of composite materials in various applications. This novel technology can provide crucial material integrity data that could help reduce costs, increase system safety, and reduce the risk of component failures. Implementation of this project will significantly enhance the infrastructure for research and education at New York Institute of Technology. The equipment acquired for this project will be used to develop a research and education program in the field of microwave/antenna engineering. Graduate and undergraduate students, including females and individuals from minority groups underrepresented in the electrical engineering field, will receive practical training in antenna and microwave design using state-of-the-art hardware and software, and thus acquire a unique skill set that prepares them for the demands of the national high-tech industry. These activities have positive and societally relevant outcomes for minorities and women, helping to remove barriers to participation in electrical engineering and engineering education in general.
The proposed microwave imaging technique is based on holographic imaging concepts already proved successful in security screening and other applications. These techniques are fast and robust to noise. They will be modified for applications such as non-destructive testing of composite pipes, in which the objects are in the extreme near-field of the antennas whose physical size cannot be ignored. In contrast to previous near-field holographic imaging techniques, the modified techniques using circular deconvolution concept will address the periodicity of the functions along the azimuthal direction in a cylindrical imaging setup. Furthermore, the solution process in near-field holography will be improved to reduce underestimation of features that are farther away from the antennas. This improvement will be implemented via an approach originally used for electroencephalography (EEG)-based brain source localization. Furthermore, novel microwave tomography techniques will be studied to alleviate the limitations imposed by the use of Born approximation in holographic techniques. In this task, holographic techniques will be combined with nonlinear imaging approaches to devise new microwave tomography techniques that are efficient in terms of cost and time. This will allow inspection of larger and higher contrast defects. Two configurations will be studied for imaging: (1) wideband single-receiver antennas and (2) narrow-band multiple-receiver antennas. Parameters affecting resolution in each configuration, including number of frequencies, number of antennas, angular distance between antennas, and radial distance between imaged surfaces, will be studied. Validity of the proposed techniques will be demonstrated via simulation and experimental setups. In addition, a compact and cost-effective imaging setup will be developed using RF data acquisition circuitry and custom-designed antenna arrays. This new microwave inspection technology can potentially revolutionize the non-destructive testing of composite and non-metallic materials.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
