Mechanisms of damage propagation in carbon composites under high impulse current magnitudes

摘要

In this investigation, the damage caused by large-magnitude lightning impulse currents was studied in the low Amperes and high kiloamperes current ranges. For the low current up to 350A tests, 150 mm ?? 150 mm square carbon composite material samples with a thickness of 2 mm and having a fastener and metal ring were used. For the high current tests using the D Waveform with magnitudes up to 70kA, two square samples of 550 mm ?? 550 mm were used with a thickness of 5 mm. The dent depth and ply level damage due to the waveform D lightning impulse current was estimated using scanning electron microscopy. It was found that the mechanical strength for samples impacted with 350 A current did not show any significant change in mechanical parameters whereas mechanical strength was considerably reduced for samples subjected to lightning current of more than 11kA magnitude.