Influence of Electrical Conductivity of Composites on Ablation Damage Degree Subjected to Lightning Strike

Abstract

According to the energy conversion relationship during the lightning strike, a lightning damage analysis model based on coupled electrical-thermal simulation for composites was established. The variation of electrical conductivity of the composite with pyrolysis was considered in the model. By means of the model, the lightning ablation damage of the composite material with multiple changes of conductivity was compared in three directions. The results show that under the same lightning current parameters, the electrical conductivity changes of composite materials in different directions have different effects on the ablation damage caused by lightning strikes. When the electrical conductivity along the fiber direction increases, both the apparent damage area and the damage depth decreased. While the electrical conductivity perpendicular to the fiber direction increases, the apparent damage area increased and the damage depth decreased. When the electrical conductivity along the thickness increases, the apparent damage area increased and the damage depth increased. When the conductivity along any of the three directions increases , the total damage volume of the composite decreased. When the conductivity of each direction increases by 1, 2, 3 orders of magnitude, the greatest changes in damage volume are observed along the fiber direction, which are decreased by 47.83 %, 75.08 % and 97.82 % respectively, followed by changes along the thickness direction, which are decreased by 36.25 %, 53.44 % and 65.54 %, and the least changes are perpendicular to the fiber direction, which are reduced by 8.72. %, 12.58 % and 24.76 %. The increase of the conductivity of the composite material play a significant role in lightning strike protection. A comprehensive assessment of the lightning protection effect requires a combination of two-dimensional damage and three-dimensional damage.

Keywords

• lightning strike ablation damage
• electrical conductivity change
• damage volume
• comprehensive assessment