Defect Detection in ISC Cylinder Using Spoof Plasmon Polaritons

NASA is exploring the use of microwave Spoof Plasmon Polaritons (SPP) to detect defects in Integrally Stiffened Cylinders (ISC). This work investigates the detection of simulated defects in the form of aluminum wires to replicate manufacturing inclusions. These wires ranged in size from as small as 10 mm long and 3.1 mm dia. to 50 mm long 3.1 mm dia., placed between the stiffeners of an ISC. SPPs act as a chain of microwave cavity resonators where added metal changes the volume of the cavity. These changes manifest as changes in the electrical parameters (such as changes in the impedance) which can be measured by a vector network analyzer.