Experimental study of the damage behaviour of laminated CFRP composites subjected to impulse lightning current

Abstract

Compared with traditional metal alloy materials, carbon fibre-reinforced polymer (CFRP) composites have many excellent advantages except for being vulnerable to lightning strike damage. This paper presents a study on the damage behaviour of CFRP laminates exposed to impulse lightning current. Measurement of near-field lightning mechanical impact on the CFRP laminates was achieved by a self-established device that effectively overcome the strong electromagnetic inference. The damage results assessed by non-destructive techniques showed that the damage degree was intensified by increasing current amplitude for CFRP samples, including apparent and bulk damage. For samples with different surface conditions, the presence of insulating epoxy resin layer dramatically exacerbated the lightning strike damage, while expanded copper foil protection mitigated the damage considerably. It was found from the mechanical impact measurement that there is a good proportional relationship between the maximum impact forces and the action integral calculated with their corresponding time for CFRP samples. CFRP coated with insulating layer subjected to stronger mechanical impact, which is almost twice as large as pristine CFRP did under the same current level. The mechanical force impacted on CFRP protected with expanded copper foil was comparable to that of unprotected CFRP. Through analysis, it was concluded that the significance of mechanical effects on the lightning damage behaviour of CFRP composite depends on the thermal effects and vice versa.