Mesoscopic study on mechanical properties and dynamic damage characteristics of self-healing microcapsule

WITHDRAWN: Cross-scale modeling of Microencapsulated self-healing composite with multiphase medium and their damage competition behavior

“…And thus, he also considered that the microcapsule ruptures first in the equatorial region. Contradictory to the above conclusion, Sun [17] demonstrated that the polar region of the microcapsule is the region where the external load is in direct contact with the capsule wall, and therefore he indicated that the polar region is the location where the stress is the highest and the damage occurs first, which is similar to the findings of Zhang [4] and Yin [18]. Moreover, in their further studies, they have shown that during the dynamic damage process of a single microcapsule, the crack extends from one pole to another along the meridian, and the damage can only evolve into a single main crack due to the instantaneous release of energy during rupture.…”

“…The resin is replaced by round particles smaller than the minimum aggregate particle size, with a size of 0.1 mm and a volume fraction of 10%. In addition, the single microcapsule is also used from our previous research [18] with a diameter distribution from 140μm to 220μm and a volume fraction of 1%. Considering the efficiency of numerical calculations, it further assumes that the aggregates with particle size <0.3 mm form a bonding agent mixture with the resin in the form of filler, and the local enlargement is shown in Fig.…”

“…Microcapsules in PRSC have a small volume fraction and almost an order of magnitude difference in structural dimensions from the aggregate, and studies have shown that the interaction between the microcapsules becomes negligible in terms of damage promotion when the microcapsules are approximately more than one microcapsule diameter away from each other [27], and thus the microcapsules can be assumed to be relatively independent and completely encapsulated in the matrix in PRSC. Neglecting the influence of the restorative agent inside the microcapsule and assuming that it is a hollow shell structure and an ideal sphere with the same wall thickness everywhere, based on Chen's experimental data and Yin's further numerical study [18], the microstructural model of the microcapsule is developed with the microcapsule diameter μm 180 = D and the wall thickness μm 10 = H , as shown in Fig. 3(d).…”

“…However, the parameters affecting the mechanical strength of each phase medium at the mesoscale are complex and diverse, but our previous studies have shown that the diameter and the wall thickness of the microcapsule are the key parameters affecting the dynamic modulus of the microcapsule [18], and further studies have shown that the microcapsule dynamic modulus is the key parameter to determine whether the interface between the microcapsules and the matrix is debonded or not [9]. Based on the above research results, this study only controls the mechanical strength of each phase medium in MSE through the interparticle bond strength (pb_ten in the PFC) (because pb_ten is the most sensitive parameter affecting the particle assemblage) to qualitatively discuss the effect of the mechanical strength of each phase medium in the self-healing system on the damage competition.…”

“…The microcapsule wall thickness and radius play a decisive role in the dynamic modulus of microcapsules [4,18], so the mechanical strength and self-healing ability of a single microcapsule can be coordinated theoretically by the core-to-wall ratio (microcapsule restorative agent volume/microcapsule volume). However, when the core-to-wall ratio and the aggregate gradation are determined, the volume fraction of microcapsules in self-healing composites is an essential factor affecting the macroscopic strength and self-healing ability of the material.…”