Experimental and multi‐scale finite element modeling for evaluating healing efficiency of electro‐sprayed microcapsule based glass fiber‐reinforced polymer composites

Microcapsule based glass fiber-reinforced polymer (GFRP) composites have attracted enormous attention due to enhancement of structures' longevity, reducing expenses, and simplicity of fabrication process. In this study, a micromechanical model of a woven E-glass/epoxy composite containing microcapsules was developed based on finite element analysis (FEA). Modified sequential adsorption algorithm was chosen to generate and disperse microcapsules in three types of representative volume elements (RVEs). Also, mechanical properties of microcapsules and composite were assigned based on nanoindentation tests and standard experimental tests, respectively. Eventually, multi-scaling method was implemented to homogenize maximum tensile stress, and subsequent evaluation of tensile after impact (TAI) healing efficiency. Therefore, a healing efficiency of 71% was obtained based on three types of simulations encompassing low-velocity impact (LVI) and quasi-static tensile tests on the RVEs. In order to validate the results; first, an electrospraying set-up was exploited to fabricate multicore microcapsules. The fabricated microcapsules contained mercaptan hardener and epoxy resin as the healing agents, and they were covered by alginate shell. Second, incorporated composite specimens with microcapsules were fabricated via the hand-layup method. The average TAI healing efficiency of 67% was achieved by experimental tests. Furthermore, scanning electron microscope images of the fractured surfaces confirmed rupture of microcapsules in the LVI test.