A B S T R A C T The fracture of bone is a health concern of increasing significance as the population ages. It is therefore of importance to understand the mechanics and mechanisms of how bone fails, both from a perspective of outright (catastrophic) fracture and from delayed/time-dependent (subcritical) cracking. To address this need, there have been many in vitro studies to date that have att...

– We consider fractures in a stratified composite material with solid layers separated by thin slices of extremely soft matter. Viscoelastic effects associated with the soft layers are taken into account via the simplest model for weakly cross-linked polymers. We find that certain small cracks running along layers take a new " trumpet " shape quite different from previously known shapes. Introd...

Three separate aspects of cutting are investigated which complement other papers on the mechanics of separation processes presented at this interdisciplinary Theo Murphy meeting. They apply in all types of cutting whether blades are sharp or blunt, and whether the material being cut is 'hard, stiff and strong' or 'soft, compliant and weak'. The first topic discusses why it is easier to cut when...

A fracture mechanics approach was employed to develop a model that can predict the penetration force during quasi-static needle insertion in soft tissue. The model captures a mechanical process where the sharp needle produces a crack that is opened to accommodate the shaft of the needle. This process involves the interchange of energy between four distinct phenomena: the work done by the needle...

The cleavage fracture toughness of steels was mezzo-scopically analyzed on the basis of the statistical local fracture criterion approach. The statistical stress criterion at the crack tip region suggests that the cleavage fracture toughness in steels can be described as a function of the yield stress, the cleavage fracture stress, and other mechanical properties of the materials. Formulation o...

the basic trait in the ceramics is their high brittle or low fracture toughness, and the main criteria in the design and application is specifying the fracture toughness in ceramics. in this paper, a new method is proposed to determine the fracture toughness of ceramics, which is enhanced in lowering the cost of fracture toughness determination relative to the previous methods. hence due to the...