Recently proposed phase-field models offer self-consistent descriptions of brittle fracture. Here, we analyze these theories in the quasistatic regime of crack propagation. We show how to derive the laws of crack motion either by using solvability conditions in a perturbative treatment for slight departure from the Griffith threshold, or by generalizing the Eshelby tensor to phase-field models....

Two major mechanisms that could potentially be responsible for toughening in mineralized tissues, such as bone and dentin, have been identified-microcracking and crack bridging. While evidence has been reported for both mechanisms, there has been no consensus thus far on which mechanism plays the dominant role in toughening these materials. In the present study, we seek to present definitive ex...

The majority of fracture mechanics studies on the toughness of bone have been performed under tensile loading. However, it has recently been shown that the toughness of human cortical bone in the transverse (breaking) orientation is actually much lower in shear (mode II) than in tension (mode I); a fact that is physiologically relevant as in vivo bone is invariably loaded multiaxially. Since bo...

A new probabilistic model describing the fatigue crack growth with retardation due to random overloads is developed. First, a crack growth equation is formulated based upon the Flber law, where a concept of retardation factor is introduced to quantify the retardation effect. Next, a new approach is discussed for describing the temporal variation of the retardation factor by the use of a system ...

Dynamic crack propagation in a unidirectional carbon/epoxy composite is studied through finite element analyses of asymmetric impact (shear loading) of a rod against a rectangular plate. A finite deformation anisotropic visco-plastic model is used to describe the constitutive response of the composite. Crack propagation is simulated by embedding zero thickness interface element along the crack ...