The continuous current component of lightning current has obvious ablation effect due to its long duration time and large amount of transfer charge

and it is the most popular item in the evaluation of lightning direct effect on aircraft surface materials. GJB 3567 and other relevant test standards require test gap distance between high voltage electrode and test object not less than 5 cm in order to simulate the arc root effect. Consequently

we experimentally investigated continuous current of lightning current on the ablation characteristics of aluminum alloy sheets

and studied the influences of positive and negative polarity of current

the length of the gap

and high voltage electrode materials on continuous current waveform and arc ablation effect. The results show that effects of the gap length and the high voltage electrode type have no obvious ablation effect

where the continuous current polarity will affect current waveform and the ablation effect. Positive arc ablation effect is generally concentrated in one or two 6 mm×4 mm of the bulge

and aluminum alloy plate with white ablation traces

negative arc ablation effect is more dispersed

showing a number of small ablation point

and aluminum plate without white traces. Positive and negative lightning direct effect test are necessary to separately identify the different damage effect. The results are important to the revision of the standard for clearing electrode type and gap requiement.