Lightning Protection Design Concepts for Advanced Composite Structures

Abstract

Graphite and boron epoxy composite aircraft structures are vul­ nerable to lightning strike damage if not properly designed. Conven­ tional lightning protection design concepts need to be modified by placing special emphasis on light weight, low cost, and ease o f mainte­ nance aspects o f the design. This paper introduces two new design concepts: (1) the isolation concept — the complete isolation of advanced composite structure from lightning current paths and (2) the conductive concept — the use o f graphite composite structure to safely conduct lightning currents. Through the proper use o f these and other design concepts developed by the industry, advanced com­ posite aircraft structures can be adequately protected from lightning hazard. Laboratory simulated lightning test data supporting these two design concepts are presented. The applications o f these design con­ cepts including the DC-10 composite rudder design are also discussed.