GEMACS (General EM Model for the Analysis of Computer Systems) Frequency-Domain Analysis to Determine the Lightning Induced Electromagnetic Skin Current Distributions on an Aircraft

摘要

A frequency-domain electromagnetic (EM) analysis of an aircraft's EM interaction with lightning is performed by using the General EM Model for the Analysis of Complex Systems (GEMACS) to determine the EM skin current distributions on the surface of a FAA CV-580 aircraft. The Method of Moments (MOM) is incorporated in GEMACS to provide an approximate solution to Maxwell's integral equations and to determine the aircraft surface currents. A 384 segment wire grid model of the CV-580 and lightning channels is constructed for the analysis; two variations of modelling the channels is constructed for the analysis; two variations of modelling the channels are implemented. The GEMACS analysis is performed for frequencies of 0.5 MHz to 5.0 MHz, in 0.5 MHz increments. The GEMACS' predicted segment currents are used to derive wire grid frequency-domain transfer functions which are compared to: (1) actual aircraft transfer functions obtained from in-flight lightning measurements, and (2) transfer functions generated from a previously performed time-domain three-dimensional finite difference (T3DFD) EM program analysis. Results show that GEMACS can be implemented to adequately predict lightning induced aircraft skin current distributions and associated aircraft resonant frequencies. Also, GEMACS provides more EM interaction information than T3DFD and, based on CPU run times, predicts this information much more efficiently. (Thesis)