An understanding of the evolution of toughness is essential for the mechanistic interpretation of the fracture of cortical bone. In the present study, in vitro fracture experiments were conducted on human cortical bone in order to identify and quantitatively assess the salient toughening mechanisms. The fracture toughness was found to rise linearly with crack extension (i.e., rising resistance-...

Although the propagation of fatigue cracks has been recognized as a problem of clinical significance in dentin, there have been few fracture mechanics-based studies that have investigated this issue. In the present study, in vitro cyclic fatigue experiments were conducted over a range of cyclic frequencies (1-50 Hz) on elephant dentin in order to quantify fatigue-crack growth behavior from the ...

Deformation twinning at the tip of a straight crack or notch is analyzed using a phase-field method that seeks equilibrium twin morphologies via direct minimization of a free energy functional. For isotropic solids, the tendency to twin under mode I or mode II loading is found to depend weakly on Poisson’s ratio and elastic nonlinearity and strongly on surface energy and twinning shear (i.e. ei...

The problem of crack deflection in bimaterial systems is considered in this paper. The material combinations may be of piezoelectric-piezoelectric, or one is piezoelectric and the other is not. Based on the Stroh formulation for anisotropic material, Green’s functions for various bimaterial combinations are presented within the framework of two-dimensional electroelasticity, allowing the crack ...

The problem of crack branching and deflection in bi-material system is considered in this paper. The combinations may be piezoelectric-piezoelectric, or piezoelectric and non-piezoelectric. Based on Stroh's formulation for anisotropic material, Green's functions for various bi-material combinations are presented within the framework of two-dimensional electro-elasticity, allowing the crack prob...

The problem of crack path selection in piezoelectric bimaterials is considered in this paper. Based on the Stroh formulation for anisotropic material and GreenÕs functions for piezoelectric bimaterials, the crack problem is expressed in terms of coupled singular integral equations at ®rst, and then the equations are used to solve for stress and electric displacement ®elds numerically. A crack i...

This chapter surveys mathematical methods and principal results in the mechanics of fracture. Primary emphasis is placed on the analysis of crack extension as treated through methods of conti~uum mechanics. Section II begins 191