Numerical Simulation of the Fracture Behavior of Ti/SiC Composites between 20 °C and 400 °C

Abstract

The fracture behavior of a Ti-6Al-4V matrix uniaxially reinforced with SiC fibers was analyzed between 20°C and 400°C using a multiscale approach that involved the finite element simulation of a three-point bend test on a notched beam of the composite. The material in front of the notch tip was discretized taking into account the actual fiber-matrix topology in the composite panels, while the rest of the beam was assumed to be homogeneous. The numerical simulations took into account the actual deformation and damage mechanisms experimentally observed (matrix plastic deformation, stochastic fiber fracture, and frictional sliding at the fiber/ matrix interface) using the appropriate finite element tools, and the corresponding fiber, matrix, and interfacial properties were independently obtained. The results of the numerical simulations were in good agreement with the experimental load-crack mouth opening displacement (CMOD) curves and reproduced accurately the actual deformation and fracture micromechanisms around the notch tip. Moreover, the apparent fracture toughness of the composite (computed from the maximum load and the initial notch length) was also very close to the experimental values, showing the potential of this multiscale approach to carry out ''virtual'' fracture tests in the computer once the physical mechanisms of deformation and fracture are included in the model and the corresponding micromechanical parameters are carefully measured.

Overcoming the limitations of distinct element method for multiscale modeling of materials with multimodal internal structure

“…The available structural and mechanical models of interfaces can be conventionally assigned to two basic concepts: (i) implicit account of the interface zone (without regard for its geometric parameters and property gradients) [14,[54][55][56][57][58][59] and (ii) explicit account of the interface as an independent structural element [60][61][62]. In the first case, the major parameters characterizing the interface are its strength properties (''strong interfaces'' or perfect bonding).…”

“…The basic characteristics of sintered metal-ceramic composites are the internal structure and mechanical properties of phase interfaces. Owing to the specifics of the production technology of such materials, rather wide zones of variable chemical composition (transition zones) with a width of up to several micrometers form at phase interfaces [49,59]. The transition zones have a complex internal structure.…”

A methodology to measure the interface shear strength by means of the fiber push-in test

“…The interface behavior was characterized by a cohesive crack model, as in our previous analysis of interface fracture in composites [12,22,23]. The cohesive model relates the total stress acting on the interface, t = y{t n ) 2 + t 2 t + t 2 , with the corresponding displacement jump, <5 = JS 2 , + S 2 + S 2 , where t n , t t and t s are, respectively, the normal and tangential stresses transferred by the interface.…”

“…They use standard composite materials and include the fiber push-out test [7][8][9][10][11][12][13], the slice compression test [14], and the fiber push-in test [15,6,[16][17][18]. The application of the slice compression test to polymer-matrix composites is not obvious while the push-out needs a cumbersome preparation of a very thin membrane (R±50 urn), leading to the fiber push-in test as the best alternative.…”

Virtual testing of advanced composites, cellular materials and biomaterials: A review

“…Fracture resistance of a composite ply was also determined using the virtual test laboratory by explicitly modelling the interaction of crack propagation with microstructure of the FRPs and braided plies [45][46][47].…”