Concrete is a so called quasibrittle material which, despite predominantly elastic material response, exhibits in tension loading a stable non-linear fracture response, when tested under displacement control. The reason for the non-linearity is the development of a fracture process zone, in front of the crack, due to micro-cracking and crack bridging. The effect of the fracture process zone is ...

Recently published data for fracture in human humeral cortical bone are analyzed using cohesive-zone models to deal with the nonlinear processes of material failure. Such models represent the nonlinear deformation processes involved in fracture by cohesive tractions exerted by the failing material along a fracture process zone, rather than attributing all damage to a process occurring at a sing...

Mollusk nacre is a prototypical biological inorganic-organic composite that combines high toughness, stiffness, and strength by its brick-and-mortar microstructure, which has inspired several synthetic mimics. Its remarkable fracture toughness relies on inelastic deformations at the process zone at the crack tip that dissolve stress concentrations and stop cracks. The micrometer-scale structure...

Fatigue and fracture mechanisms have been studied in a steel-based metal matrix composite (MMC), comprising a 316L austenitic matrix reinforced with 25 wt% particulate titanium diboride (TiB2). The fracture toughness was determined in the as-HIPped condition as being slightly below 30 MPa√m. Fatigue crack growth rates have been determined, and corrected for the effects of crack closure. The fra...

in this paper, a finite element model is developed for the fully hydro-mechanical analysis of hydraulic fracturing in partially saturated porous media. the model is derived from the framework of generalized biot theory. the fracture propagation is governed by a cohesive fracture model. the flow within the fracture zone is modeled by the lubrication equation. the displacement of solid phase, and...

1 The Effect of Cohesive-Law Parameters on Mixed-Mode Fracture R. B. Sills and M. D. Thouless Department of Mechanical Engineering Department of Materials Science & Engineering University of Michigan Ann Arbor, MI 48109-2125, USA Abstract Cohesive-zone models of fracture provide a framework that allows a smooth transition between a strength-based approach to fracture and an energy-based approac...

The fracture front in concrete, as well as rock, is blunted by a zone of microcracking, and in ductile metals by a zone of yielding. This blunting causes deviations from the structural size effect known from linear elastic fracture mechanics (LEFM). The size effect is studied first for concrete or rock structures, using dimensional analysis and illustrative examples. Fracture is considered to b...

Fracture surface of Zircaloy-2 specimens tested under constant crosshead speed in CH3OH/0.4 Vol. %HCI solution with and without selenium (25 ppm) addition was studied. Using a combined process of deformation and annealing, coarse grained material was also obtained and examined. Two modes of stress corrosion crack propagation were observed: an intergranular zone caused by stress assisted anodic ...

Skeletal tissues from children sustaining acute skeletal trauma were analyzed with detailed radiologic and histologic techniques to assess the failure patterns of the developing skeleton. In the physis- and epiphysis-specific fracture propagation varied, usually going through the portion of the hypertrophic zone adjacent to the metaphysis. However, the physeal fracture in types 1 and 2 sometime...