Lightning strike protection of composites

This study examines the evolution of damage in graphite/epoxy composite laminates due to lightning strikes To clarify the influence of lightning parameters and specimen size, artificial lightning testing was performed on a series of laminated composite specimens Damage was assessed using visual inspection, ultrasonic testing, micro X-ray inspection, and sectional observation The results showed that the damage modes can be categorized into fiber damage, resin deterioration, and internal delamination modes Damage progression is governed by the strong electrical orthotropic properties of the laminates, and the lightning parameters defining impulse waveform show strong relationship with certain damage modes, though specimen size and thickness variation barely affect damage size

Artificial lightning testing on graphite/epoxy composite laminate

One important application of nanocomposites is their use in engineered structural composites. Among the wide variety of structural applications, fiber-reinforced composites for aerospace structures have some of the most demanding physical, chemical, electrical, thermal, and mechanical property requirements. Nanocomposites offer tremendous po tential to improve the properties of advanced engineered composites with modest additional weight and easy integration into current proc essing schemes. Sig nificant progress has been made in fulfilling this vision. In particular, nanocomposites have been applied at numerous locations within hierarchical composites to improve specific properties and optimize the multifunctional properties of the overall structure. Within this ar ticle, we review the status of nanocomposite incorporation into aerospace composite structures and the need for continued development.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0883769400009374

Challenges and Opportunities in Multifunctional Nanocomposite Structures for Aerospace Applications

https://pureadmin.qub.ac.uk/ws/files/9419808/pure.pdf

Nonlinear numerical modelling of lightning strike effect on composite panels with temperature dependent material properties

This paper deals with the direct effects of lightning strike on aircraft structures. In a first part, the phenomenology of lightning arc attachment on aircraft is introduced. Some specific features of lightning arcs observed in flight or created in the laboratory are presented. Some recent developments and results from numerical simulations are shown. The shapes, the behaviors and other specific points are compared with experiments, in order to bring to light some explanations on the complex features of lightning arcs. The second section presents the direct effects of lightning on aircraft skins. Both thermal and mechanical constraints are introduced and illustrated with experimental and numerical results. The negative effects of the paint layer on the damaging of composite and metallic materials are illustrated. The last section is focused on the direct effects of lightning on fasteners. The main mechanisms occurring during sparking phenomena are presented.

https://hal.archives-ouvertes.fr/hal-01184416/document

Direct Effects of Lightning on Aircraft Structure: Analysis of the Thermal, Electrical and Mechanical Constraints

The current knowledge concerning potential lightning effects on aircraft and the means that are available to designers and operators to protect against these effects are summarized. The increased use of nonmetallic materials in the structure of aircraft and the constant trend toward using electronic equipment to handle flight-critical control and navigation functions have served as impetus for this study.

F. A. Fisher

Papers

Lightning Protection of Aircraft