Analysis of carbon fiber destruction by lighting current

Abstract

The paper considers the unique properties of conducting carbon fiber composite: specific resistivity at different directionality of layers and critical energy of layering and destruction on the basis of experimental data. High mechanical strength and low specific gravity are noted, allowing its use in aircraft engineering to improve aircraft tactical and technical data of aerial vehicles. Strong anisotropy of electrically-conductive properties affects current spreading through carbon fiber and leads to significant destruction of the material. Theoretical analysis of lightning current spreading along anisotropic-conducting material in the form of extended plate was carried out on the basis of two proposed models of carbon fiber destruction by lightning currents. For the first continuum model an exact analytical solution to the Laplace equation with Neumann boundary conditions via the Greenberg method was found. The criteria for composite destruction was found, and the radius and depth of destruction of a conductive material by lightning current were calculated. Layer-by-layer destruction is considered on the basis of carbon fiber equivalent circuit. The strong anisotropy of the material resulting in the release of full energy in the first layer is taken into account. It is shown that the destruction of the top layer changes the distribution of currents over the remaining layers. The results of numerical modeling of layer-by-layer destruction of carbon fiber for different number of layers are given. The conclusion on the application of criteria to forecast the lightning effects and optimize lightning at the stage of aircraft design is made.