Development of multifunctional hybrid metal/carbon composite structures

Abstract

The aim of this work is to design, manufacture and test a hybrid composite by embedding optimised copper or Shape Memory Alloy (SMA) wires within carbon fibre laminate for improved impact resistance, intrinsic strain sensing and impact detection capability, non-destructive testing and de-icing functionalities. It was demonstrated that with an appropriate optimisation of the wires a reduction of damaged area was experienced. It was shown that the hybrid network can work as a strain sensor by monitoring the variation of its electrical resistance under load and to identify the presence of a localised load such as an impact event. Then, non-destructive capability for assessing defects was shown where by applying an electrical current to the metal wires, heat was generated and distortion of the thermal field due to a damaged area was measured using a Step Heating Thermography (SHT) process, creating an image of the damage. De-icing operations was presented by exploiting the Joule effect where the local temperature increase was able to melt down an ice layer and hence avoid aerodynamic variation of aircraft surfaces. The results showed that the multifunctionality of this embedded smart material can improve the safety and reliability of aircraft structures and reduce maintenance costs.