Radar Absorbing Capability and Fatigue Properties of Unidirectional Carbon Fabric-Reinforced Composites

Radar absorbing materials can be exposed to very different loading conditions during their use. A fracture that may occur within the composite can affect its electrical behavior as well as its strength. For this reason, they must show mechanical strength besides their radar absorbing capability. In this study, two-layer, four-layer, six-layer and eight-layer composite plates in different stacking sequences were compared in terms of attenuation, fatigue behavior and tensile strength. Free space measurements for radar absorption were conducted in a frequency range of 6-14 GHz. Maximum reflection loss was seen in the eight layered 0 degrees/90 degrees composite with 66.89 dB. Cyclic loading was applied to carbon fiber composites in a sinusoidal waveform at a frequency of 3 Hz and the fatigue limit strength was evaluated as the maximum cyclic stress at 10(5) cycles. It is found that the maximum fatigue strength occurred in six-layered composites. SEM analysis showed that more fringing in 0 degrees/90 degrees oriented composites.