The mechanisms contributing to failure of full dental ceramic crowns under occlusal loads were studied using a unique optical approach. Model specimens comprising triple-layered crowns (veneer, core and substrate) were developed with both flat and curved occlusal surfaces and then subjected to simulated quasi-static occlusal loading using a spherical indenter. Deformation within the specimens d...

BACKGROUND Hip fractures are one of the causes of disability amongst elderly patients. External fixator and skeletal traction are two modes of treatment. OBJECTIVES The aim of this study is to compare two different treatment modes for intertrochanteric fractures in elderly patients. PATIENTS AND METHODS Sixty elderly patients with intertrochanteric fractures were randomized for treatment wi...

The energy release rate (ERR) proposed by Irwin based on a theory by Griffith [1, 2] has been extensively used as a fracture criterion in 2D for brittle domains. Under in-plane mixed mode loading (modes I+II), the direction of crack initiation from cracks and sharp V-notches was determined by the orientation at which the ERR attains its maximum. Using the newly developed asymptotic expansion pr...

The role of substrate modulus on critical loads to initiate and propagate radial cracks to failure in curved brittle glass shells on compliant polymeric substrates is investigated. Flat glass disks are used to drive the crack system. This configuration is representative of dental crown structures on dentin support in occlusal contact. Specimens are fabricated by truncating glass tubes and filli...

Fiber reinforcement is widely used in construction engineering to improve the mechanical properties of soil because it increases the soil's strength and improves the soil's mechanical properties. However, the mechanical properties of fiber-reinforced soils remain controversial. The present study investigated the mechanical properties of silty clay reinforced with discrete, randomly distributed ...

The paper presents a numerical implementation of a novel approximation scheme for Griffith’s theory of brittle fracture recently proposed in [1]. The total potential energy of a brittle body (including bulk and surface terms) is variationally approximated by a family of functionals, depending on a small penalty parameter ε. The (two-field) approximating functionals have as arguments the displac...

The present study seeks to discuss the incidence of a stress fracture in not athletes. This type pathology occurs as result repetitive number movements given region, fatigue and muscle imbalance are main responsible for these fractures, which mainly affect runners military, groups that more susceptible large amount impact In practice, has been increasing non-athletes. To do so, it reviews liter...

A nonuniform crack growth problem is considered for a homogeneous isotropic elastic medium subjected to the action of remote oscillatory and static loads. In the case of a plane problem, the former results in Rayleigh waves propagating toward the crack tip. For the antiplane problem the shear waves play a similar role. Under the considered conditions the crack cannot move uniformly, and if the ...

The Material Point Method (MPM), which is a particle-based, meshless method that discretizes material bodies into a collection of material points (the particles), is a new method for numerical analysis of dynamic solid mechanics problems. Recently, MPM has been generalized to include dynamic stress analysis of structures with explicit cracks. This paper considers evaluation of crack-tip paramet...

In spite of advances in techniques and improvements in surgical implants, confusion still prevails regarding use of specific implants in distal femur fracture. Fractures in the distal femur have posed considerable therapeutic challenges throughout the history of fracture treatment. Most of these surgical failures were due to inadequate fixation of the fracture fragments. The Aim of the study is...