Computational Zoning of Unconventional Aircraft

The protection of aircraft from lightning strikes, both
triggered and intercepted, is an essential component in the
aircraft development and certification process. In the past,
lighting strikes to aircraft have caused catastrophic accidents
that have promoted extensive studies into the mechanisms
behind lightning events and their mitigation strategies. These
recommendations have led to protective measures in the form
of wire mesh and diverter strips on nonmetallic surfaces,
removing sources of spark-triggered ignition in the fuel
system, adequate grounding and wire bundle shielding
strategies, and route management to avoid thunderstorms.
While significant progress has been made in aircraft lighting
protection, much of what we know about aircraft triggered
lightning comes from historical experience and testing. Next
generation aircraft designs may not conform to the same
assumptions under which models for existing aircraft are
valid.
We present a general computational tool for the prediction of
the first and second attachment points on arbitrary aircraft
geometries. The tool couples numerical electrostatics
simulation to a predictive attachment model, and uses open
source software which is freely available. The attachment
model follows similar methods developed by Onera and the
University of Padova in the 1990s, but accounts for both
positive and negative first leader inception. Additionally, a
feature to determine the optimal aircraft charge has been
incorporated into the tool, following prior work by our team
on triggered-lightning risk-reduction measures. The tool will
be demonstrated by application to the MIT D8 “Double
Bubble” aircraft.