Interactions between propagating cracks and bioinspired self-healing vascules embedded in glass fibre reinforced composites

Abstract

International audienceThis study considers the embedment of a bioinspired vasculature within a composite structure that is capable of delivering functional agents from an external reservoir to regions of internal damage. Breach of the vascules, by propagating cracks, is a crucial pre-requisite for such a self-healing system to be activated. Two segregated vascule fabrication techniques are demonstrated, and their interactions with propagating Mode I and II cracks determined. The vascule fabrication route adopted played a significant role on the resulting laminate morphology which in-turn dictated the crack-vascule interactions. Embedment of the vascules did not lower the Mode I or II fracture toughness of the host laminate, with vascules orientated transverse to the crack propagation direction leading to significant increases in G and G through crack arrest. Large resin pockets were found to redirect the crack around the vascules under Mode II conditions, therefore, it is recommended to avoid this configuration for self-healing applications

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

“…[19] This method is based on the ASTM D5528-01 standard for Mode I crack opening displacement of FRP composite materials, [27] a unidirectional (UD) glass fibre reinforced epoxy composite I crack opening displacement has been thoroughly investigated to provide successful crackmicrovascule interconnectivity to allow SHAs to wet out the crack planes and re-bond fractured surfaces. [19,20] Test specimens were initially fractured, unloaded from the test machine, allowed to heal and subsequently re-tested to failure following the same protocol.…”

“…[10] A bio-inspired vascule approach [11] to self-healing in high performance thermoset composite materials has been extensively researched by Bond, Trask and co-workers over the past 10 years, primarily due to the integration challenges and volume limitations of microcapsulebased systems. Hollow glass fibres (HGFs) [12][13][14][15][16] and microvascular channels [17][18][19][20] have successfully demonstrated reliable methods for self-healing agent (SHA) delivery to damaged areas through multiple mixed-mode testing. 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.…”

Self-healing and self-repairing technologies

“…In the other case, tin solder is included in the laminate to create the vascular network and is then melted at high temperatures [121,122]. Modelling such composite laminate structures, it can be determined where damage is most likely to occur and, thus, where the healing resins must be located ideally [132].…”

A computational model for the flow of resin in self-healing composites

“…The precise healing strategy employed varies with the intended structural application, and the nature and magnitude of the damage. For example, microcapsules [1,2,3] distributed appropriately may be sufficient to heal initiating defects and arrest slow propagating cracks, while embedded liquid filled hollow glass fibres [4,5,6] or vascular networks [7,8,9,10,11,12,13] are ideal for facilitating the bleeding of healing agent throughout multiple crack planes within large scale damage.…”