Electromagnetic nondestructive evaluation of composites for Navy ship applications

Glass fiber reinforced polymer composites are being considered by the US Navy for top-side structures on ships. Electronic equipment and personnel inside these structures must be protected from electromagnetic interference and radiation hazards from friendly and hostile sources. Since these composites are nondesctructive, metallic layers of various architectures, composition, and lay-ups have been incorporated into them for electromagnetic shielding. This paper will present electromagnetic NDE data on some of these metal-clad, nonconductive composites. Low frequency eddy-current test results will be compared to the electromagnetic shielding performance at microwave frequencies. Issues associated with corrosion will be discussed.