FDTD simulation of lightning current in a multi-layered CFRP material

Abstract

Transient distribution of lightning current, which flows in a layered carbon fibre reinforced plastic (CFRP) material of aircraft, is analysed using the three dimensional (3D) finite difference time domain (FDTD) method with triangular-prism cells. One of the principal reasons for thermal sparks, which would occur on or in a CFRP aircraft body struck by lightning, is the concentration of lightning current near fasteners that connect body components or members. Therefore, it is important to analyse the transient distribution of lightning current in a layered CFRP material with fasteners for designing its lightning protection. Although rectangular or cubic cells are usually used in FDTD simulations, triangular-prism cells are employed in the present study for appropriately representing CFRP layers, each of which has anisotropic conductivity. An experiment for evaluating transient current distribution in a layered CFRP material is also carried out. The FDTD- computed current distribution agrees reasonably well with the corresponding measured one. This shows that the present FDTD simulation with triangular-prism cells is valid and effective in the analysis of lightning current in a layered CFRP structure, each layer of which 45-, 90,-45- or 0-degree anisotropic conductivity.