Deflected trajectory of a single fluid-driven crack under anisotropic in-situ stress

Modeling of fatigue crack closure in inclined and deflected cracks

A 2-dimensional, elastic-plastic finite element model has been developed to simulate plasticity induced crack closure in slanted and deflected cracks growing outside the small scale yielding (SSY) regime. The finite element model allows for contact between deformable surfaces to capture the complex contact interaction between the crack faces. Coulomb’s friction law has been used to model fricti...

Effect of Stress Triaxiality on Yielding of Anisotropic Materials under Plane Stress Condition

The triaxiality of the stress state is known to greatly influence the amount of plastic strain which a material may undergo before ductile failure occurs. It is defined as the ratio of hydrostatic pressure, or mean stress, to the von Mises equivalent stress. This paper discusses the effects of stress triaxiality on yielding behavior of anisotropic materials. Hill-von Mises’s criteria for anisot...

A Crack in an Anisotropic Elastic Slab*

Single-trajectory Opportunistic Planning under Uncertainty

An approach to planning for execution in uncertain environments is to characterise the action resource-use profiles using statistical techniques and then base predictions about action outcomes on these estimates. Because the exact profiles of actions cannot be determined prior to actual execution it is possible that these estimates will be flawed, resulting in the failure of the current plan tr...

Crack Models for a Transversely Anisotropic Medium

A commonly used model for a transversely anisotropic crack rock is that by Hudson (1980, 1981). This model is based on a simplified analysis of a thin circular crack, with displacement and stress conditions specified on the boundary. These papers have a second order correction in addition to the first order term in porosity/crack density. In this paper we compare the results of Hudson with thos...