Enhanced method in the design of microvascular self-healing system in a composite structure based on a Newtonian healing agent

Composite materials are highly valued in the aerospace industry for their exceptional properties. However, these materials have some limitations, particularly in reducing the load-bearing capacity under sudden loads even under low-speed impacts. Incorporating a self-healing system (SHS) into these materials is essential to immediately repair damage and preserve structural integrity. This study focuses on establishing a method for designing a microvascular SHS, considering the effect of the friction factor (f) on the healing agents (HA) mixture 5-ethyldiene-2-norbornene and dicyclopentadiene (ENB-DCPD) that flow inside the microvascular, and the microvascular volume fraction (VF) that affects composite strength. It is found that the 0.5 mm microvascular diameter is the most appropriate to select in this design study because it meets the design criteria. The flow within these microscale vascular systems exhibits a contrary flow phenomenon, and a shift from laminar to turbulent flow is observed (1800 < Re < 2300). The SHS is arranged in a zigzag pattern based on the analysis of low-speed impact loads that applied on the composite structure T700/QY9611. The delamination was clearly visible due to the maximum contact force, which was equal to 10.79 kN, resulting from the impact-applied load of 31.55 J. This study aims to shed light on an enhanced design method that emerged from the fusion of multiple fields, including healing agents and composite materials, structures, and microfluidics. This design approach ensure maintaining the laminate strength in addition to autonomous curing with effective healing agent flow into the prospective damage area.