Self-healing of impact damaged CFRP

The development of advanced fiber reinforced polymer's (FRP's) to achieve performance improvements in engineering structures focuses on the exploitation of the excellent specific strength and stiffness that they offer. However, the planar nature of an FRP's microstructure results in relatively poor performance under impact loading. Furthermore, significant degradation in material performance can be experienced with minimal visual indication of damage being present, a design scenario termed Barely Visible Impact Damage (BVID). Current damage tolerant design philosophies incorporate large margins to account for reduction in structural performance due to impact events, resulting in overweight and inefficient structures. An alternative approach to mitigate impact damage sensitivity can be achieved by imparting an ability for these materials to undergo self-healing. Self-healing composites would allow lighter, more efficient structures and would also offer a potentially substantive reduction in maintenance and inspection schedules and their associated costs. This paper considers the development of autonomic self-healing within CFRP, and demonstrates the strength recovery possible when a resin filled HGF system is distributed at specific interfaces within a laminate, minimizing the reduction in mechanical properties whilst maximizing the efficiency of the healing event.