Effect of Plate Thickness and Paint on Lightning Strike Damage of Aluminum Alloy Sheet

Aircraft usually avoid areas associated with lightning. However, when such areas are directly along the takeoff or landing path and cannot be avoided without delay, there is a risk of lightning strike during flight. After an aircraft has been hit by lightning, maintenance technicians have to identify the lightning entry and exit points and conduct any necessary repairs before the next flight, and must perform these tasks as quickly as possible to minimize disruption to operations. The metallic material has high conductivity and it is known that the damage is small comparing to composite material. However, the knowledge concerning about the lightning strike damage on metallic material contributes to minimize the damage size and the duration of repair.

The effect of plate thickness on lightning strike damage for 2024-T3 Aluminum alloy sheet is evaluated. Test result shows that the surface of the specimen is melt by the high heat input during the lightning strike and the area can be distinguished by the appearance. In addition, the result shows that the lightning strike damage on the specimen with paint becomes small comparing to that on the specimen without paint, and then the paint acts as insulator.