Direct Effects of Lightning on Aircraft Structure: Analysis of the Thermal, Electrical and Mechanical Constraints
L. Chemartin, P. Lalande, B. Peyrou, A. Chazottes, P.Q. Elias (Onera),
C. Delalondre (EDF), B.G. Cheron (Cnrs), F. Lago (DGA)
This paper deals with the direct effects of lightning strike on aircraft structures. In a first part, the phenomenology of lightning arc attachment on aircraft is introduced. Some specific features of lightning arcs observed in flight or created in the laboratory are presented. Some recent developments and results from numerical simulations are shown. The shapes, the behaviors and other specific points are compared with experiments, in order to bring to light some explanations on the complex features of lightning arcs. The second section presents the direct effects of lightning on aircraft skins. Both thermal and mechanical constraints are introduced and illustrated with experimental and numerical results. The negative effects of the paint layer on the damaging of composite and metallic materials are illustrated. The last section is focused on the direct effects of lightning on fasteners. The main mechanisms occurring during sparking phenomena are presented.