3D numerical simulation of composite discharge effect under lightning strike

A 3D FE model of long air gap and composite laminate was built. The positive streamer growth probability model of a long rod-plate gap was adopted as a stochastic discharge model based on the traditional streamer theory. The detailed simulation process includes: calculating the electric potential at each grid point in air gap, listing routes of all streamers developed around the pole, calculating the growth time of route developed for each streamer and defining the route with minimum growth time as the prior selected one. When the streamer reaches the composite plate, the cross point of the streamer and plate was regarded as the attachment point of lightning strike. A direct effect analysis was carried out to obtain the potential, temperature and heat stress distribution of composite plate can be obtained under the high voltage wave strike of lightning. The results show that the high potential, temperature and heat stress produced instantaneously by fast streamer mainly spread out symmetrically along the direction with maximum conductivity on top plate. The analysis results, provided as a quality description of the process, are only the preliminary. In order to more accurately simulate the process of composite discharge effect under lightning strike, the damage mechanism of ablation and the thermodynamics for composite laminate need to be further taken into account.