Self‐Healing Fibre Reinforced Composites via a Bioinspired Vasculature

Abstract

This paper demonstrates the fi rst steps towards self-healing composites that exploit a design philosophy inspired by the damage tolerance and self-repair functions of bone. Cracking in either fi bre reinforced polymers (FRP) or bone, if left unattended, can grow under subsequent cyclic stresses eventually leading to catastrophic failure of the structure. On detection of cracks, an FRP component must be repaired or completely replaced, whereas bone utilises a series of complex processes to repair such damage. Under normal circumstances, these processes allow the skeleton to continually perform over the lifespan of the organism, a highly desirable aspiration for engineering materials. A simple vasculature design incorporated into a FRP via a "lost wax" process was found to facilitate a self-healing function which resulted in an outstanding recovery ( ≥ 96%) in post-impact compression strength. The process involved infusion of a healing resin through the vascule channels. Resin egress from the backface damage, ultrasonic C-scan testing, and microscopic evaluation all provide evidence that suffi cient vascule-damage connectivity exists to confer a reliable and effi cient self-healing function.

Metal Triflates as Catalytic Curing Agents in Self‐Healing Fibre Reinforced Polymer Composite Materials

“…Norris et al have further developed this concept with the stimuli triggered delivery of a pre-mixed commercial epoxy SHA into an aerospace grade composite material, when subject to low energy impact damage, to recover compression after impact (CAI) strength. [21][22][23] As previously discussed, [9] the SHAs implemented in this study offer significant improvements over alternative well documented self-healing systems, for example those employing Grubbs' catalyst, [24] polydimethylsiloxane (PDMS)/di-n-butyltin dilaurate (DBTL) [25] and epoxy/maleimide. [26] These improvements include host matrix compatibility, catalytic activity under mild conditions, relatively low cost and toxicity, high stability, commercial availability and system tailorability.…”

“…[21] Initial fracture toughness testing of five baseline FRP specimens at a displacement rate of 2 mm/min resulted in progressive crack propagation along the midplane at an average load of 27.2 N; a failure mode typical of Mode I loaded UD test…”

Active Cooling of a Microvascular Shape Memory Alloy‐Polymer Matrix Composite Hybrid Material

“…Active cooling systems are used extensively in electronics, [2] fuel cells, [3,4] high power batteries, [5] micro-electro-mechanical systems (MEMS), [6] and spacecraft systems. [7][8][9] In addition to cooling, vascular networks in PMCs enable self-healing, [10][11][12][13] electromagnetic modulation, [14] and damage detection. [15][16][17] Here, we fabricate a vascular network into each phase of a bilayer nickel-titanium (NiTi)/glass fiber reinforced epoxy hybrid by the Vaporization of Sacrificial Components (VaSC) technique.…”

In-situ repair of composite sandwich structures using cyanoacrylates

“…Norris et al 8 have shown that parameters such as the vascule diameter [26,27] and orientation 9 relative to the fibre reinforcement [28] strongly affect the ultimate performance of the 10 composite. A key finding is that alignment of the vasculature in the fibre direction is 11 highly preferable as it eliminates the requirement to cut plies and introduce fibre 12 discontinuities into the system.…”