Evaluation of complexity of wire harness models in a HIRF environment

Canonical aircraft model simulations were performed using a full wave finite-difference time-domain (FDTD) code with an integrated multi-conductor wire harness algorithm. Wire harness bundle currents and their transfer functions were obtained in the frequency range of 1 - 400 MHz, corresponding with the ARP 5583 requirement for the low level swept currents (LLSC) aircraft certification tests. In order to demonstrate the importance of including cable complexities when predicting wire harness responses in a high-intensity radiated field (HIRF) environment, two types of simulations were performed: one that uses a simplified harness technique, and one with more realistic harness segments that include the cable contents. Comparisons between the two simulation techniques are provided. We conclude that in order to obtain realistic results, it is necessary to capture wire harness complexities in the numerical model, such as harness branching, precise conductor resistances with frequency dependent skin depth effects, and position adjustment of conductors along the length of the harness.