Self-healing of a microcapsule structure reinforced with pre-strained shape memory alloy wires
Combination of microcapsules and shape memory alloys (SMAs) is one of
the promising self-healing mechanisms. Although there are several
parameters which affect the performance of such structures, limited
studies are performed on this combined healing mechanism. In this
work, we study the performance of such a composite structure using a 3-
D finite element model consisting of matrix, glass microcapsule, healing
agent and Ni-Ti SMA wire. After examining the results, the effect of
shape memory alloy wires on increasing the maximum fracture stress
was observed. Moreover, the effect of radius of shape memory alloy
wires, thickness ratio and volume fraction of microcapsules and interface
strength on ultimate fracture stress are investigated. Also, as a key
parameter in self-healing performance, the crack opening distance
decreased from 5 μm to 0.008 μm using 0.5% volume fraction of shape
memory wires without pre-strain. In the case that the wires have a prestrain
of 1%, this value reaches almost zero and a compressive stress is
induced between fracture surfaces which can enhance the healing
process and adherence of healing agent.
