Transverse Failure Behavior of Fiber-epoxy Systems

Abstract

The transverse failure response of unidirectional fiber-epoxy systems is studied by means of finite element simulations. An interface damage model is used for modeling fiber debonding and epoxy cracking. The convergence of the numerical results upon mesh refinement is analyzed. It is found that the failure response depends on the relative strength and relative toughness of the fiber-epoxy interface and the epoxy matrix. The tensile failure response of epoxy systems containing multiple fibers is also analyzed. In addition, the simulations demonstrate the influence on the failure response by the relative strength of the fiber-epoxy interface and the epoxy matrix, and by the fiber volume fraction and fiber distribution. The simulated fracture patterns are shown to be in good agreement with experimental observations reported in the literature.

Numerical homogenization of cracking processes in thin fibre-epoxy layers

“…In addition, as observed in recent micromechanical computations [29], this difference may further become larger when the strength of the fibre-epoxy interface is lower than the strength of the epoxy. This is, because under such conditions the cracking path is forced to run along the perimeter of fibres and consequently increases in length, thereby enlarging the effective fracture toughness of the fibre-epoxy system (similar to what has been demonstrated in this paper for samples with imperfections at fibre-epoxy interfaces).…”

Meso-scale fracture simulation using an augmented Lagrangian approach

“…A deeper analysis of the mesh sensitivity of the method is carried out and the results are compared with those obtained by Cid Alfaro et al (2010). Figure 14 shows the simulated square cell with 125 µm side and a 30% of volumetric fiber content.…”

“…Figure 14 shows the simulated square cell with 125 µm side and a 30% of volumetric fiber content. Table 5 shows the mechanical properties used for the matrix and the fibers, and Table 6 presents the meshes used by Cid Alfaro et al (2010) Table 5. Material properties for longitudinal fiber reinforced epoxy matrix.…”

“…The crack is first propagated within the matrix, then follows an arc-length of each fibre interface corresponding to a central angle of approximately 60 o (Figure 13 (b)). Figure 16 shows the load-displacement curves obtained and the comparison with the solution in Cid Alfaro et al (2010). Table 6.…”

“…More recently, interface elements were introduced in meso-scale concrete models by , López et al (2008) and Du et al (2013), among others. Cid Alfaro et al (2010) used a classical interface technology and Nguyen (2014) presented a discontinuous Galerkin approach for transverse failure analysis of unidirectional fiber reinforced epoxy.…”