Discrete modeling of crack bridging by a discontinuous platelet with a controlled interface

Abstract

a b s t r a c tCrack bridging by discontinuous fibers can make brittle materials tougher by transferring stresses from the crack tip to elsewhere in the matrix material. One important aspect of crack bridging is the nature of the interface between the fibers and the matrix material. In this paper, a two-dimensional numerical model of bridging a Mode I loaded crack by linear elastic discontinuous platelets is developed for two different types of interfaces. The first type is a perfectly bonded interface. The second type is an imperfect interface described as a stick-slip interface. A shear-lag model to predict platelet pullout is developed in detail to verify the numerical implementation of the stick-slip interface. An example of a crack tip bridged by a platelet is examined for both interfaces. The perfectly bonded interface will reduce the Stress Intensity Factor (SIF) of the crack greatly but introduces new stress concentrations at the platelet ends. The stick-slip interface can be tailored to also reduce the SIF while not introducing new stress concentrations.

Effect of viscoelasticity on interfacial stress transfer mechanism in the biocomposites: A theoretical study of viscoelastic shear lag model

“…However, some researchers [27,29] considered the interfacial friction behavior between fiber and matrix, and postulated an elastic-linear softening-frictional model (Fig. 2f).…”

“…In a similar manner, elastic-frictional model ( Fig. 2g) was employed by Sanborn and Prévost [29] to investigate the platelet pullout process. For the sake of better understanding of the debonding process of fiber-matrix interface, Nian et al [30] developed a bilinear traction separation and the Coulomb friction model ( Fig.…”

Virtual testing framework for hybrid aligned discontinuous composites

“…b. The shear lag model developed in Section 2 is the first one in the literature to extend the widelyused shear-lag approach [13][14][15][16][17][18][19][20] to discontinuous hybrid composites, considering a generic non-linear response of the matrix.…”

“…A first challenge in modelling hybrid discontinuous composites is correctly capturing the effect of the discontinuities due to the fibre-ends. One widely-used approach is shear-lag models [13][14][15][16][17][18][19][20]. Although most shear-lag models in the literature consider a purely elastic [18,21,22] or perfectly plastic [20,[22][23][24]] matrix, we have developed a shear-lag framework for brick-and-mortar [19] and aligned discontinuous [25] composites which considers the full matrix constitutive law in shear, including strain-hardening and progressive failure; this framework also considers the random placement of fibre-ends [25], contrarily to most analytical models which assume perfectly staggered fibres [19,26,27] or regularly spaced fibre-ends [28].…”