Using the presented criteria for breakdown pressure in which is related to horizontal stress, hydraulic fracturing test directly used estimation of maximum situ stress. However, classical do not take into account effects near-wellbore stress field, so estimating using them accompanied by errors. A plane strain numerical model obtain pressure, effect initial crack length are considered. In this ...

statement of problem: impacts and accidents are considered as the main fac- tors in losing the teeth, so the analysis and design of the implants that they can be more resistant against impacts is very important. one of the important nu- merical methods having widespread application in various fields of engineering sciences is the finite element method. among its wide applications, the study of ...

BACKGROUND It is believed that mechanical stresses play an important role in atherosclerotic plaque rupture process and may be used for better plaque vulnerability assessment and rupture risk predictions. Image-based plaque models have been introduced in recent years to perform mechanical stress analysis and identify critical stress indicators which may be linked to rupture risk. However, large...

Abdominal aortic aneurysm (AAA) is a dilation of the abdominal aorta (above 50 % of its original diameter), which can cause death upon rupturing. It usually grows asymptomatically leading to late clinical intervention. The medical criteria to indicate surgery are based on measuring the diameter and growth rate, but in many cases aneurysms fail at uncharacterized critical values. In search of a ...

Uniaxial tension-compression fatigue behavior of 3-mol%yttria-stabilized tetragonal zirconia polycrystals was investigated. Hysteresis in the stress-plastic strain curve featured cumulative plastic strain and weakened elastic stiffness. Fracture statistics in terms of cycle-to-failure depends strongly on the maximum stress and less on the stress amplitude. Preexisting processing flaws were iden...

Two variational closure models are proposed in order to describe stress distribution and arch formation in sandpiles located on a rigid base. The maximum strength and the maximum entropy closures are shown to yield the normal stress minimum below the pile apex. Stress distributions in sandpiles are determined numerically. The force uctuations in a model regular granular assembly are studied by ...

The arterial wall is a composite where the preferred orientation of collagen fibers induces anisotropy. Though the hyperelastic theories of fiber-reinforced composites reached a high level of sophistication and showed a reasonable correspondence with the available experimental data they are short of the failure description. Following the tradition of strength of materials the failure criteria a...