Smart materials that can monitor their structural integrity in real time and repair damage will extend the life of materials used in transportation and renewable energy applications. Now, researchers from Queen Mary University of London, Lough-borough University, Warwick University and Imperial College London have taken a traditional approach and created a new self-sensing and self-healing composite material.
Researchers have demonstrated 'new' additional capabilities for restoration and structural health monitoring through a simple technique of interlacing composite laminates. While increasing the toughness of the laminate, it also has the function of easy repair, which solves the challenges of the relatively poor out-of-plane performance of the current composite materials and the inability to sense and repair internal damage, and extends the service life of the composite parts.
Self-healing strategies for most materials rely on extrinsic methods using healing agents or intrinsic systems based on reversible chemical bonds or supra-molecular interactions. However, the addition of liquid or solid healing agents to structural composites can affect their load-bearing properties and increase the complexity of the manufacturing process. Instead, the researchers staggered thin layers of thermoplastic between the carbon-fiber composite layers. To repair the damage, heat and pressure need to be applied so that the thermoplastic diffuses into the damaged area and fills the crack. The thermoplastic layer provides both the ability to self-repair without compromising mechanical properties.
In addition, users can customize the characteristics and curing conditions of the thermoplastic layers to achieve easy repair and improve fracture toughness even after multiple damage and repair cycles.
It is reported that the invention will solve a large number of scenarios that require routine maintenance and repair of composite structures, but are difficult and unrealistic to achieve, such as offshore wind turbine blades or some types of aircraft. This simple and scalable technique will also be adopted in sports or Marine composite applications.
