The fracture resistance of structures is optimised using the level-set method. Fracture resistance is assumed to be related to the elastic energy released by a crack propagating in a normal direction from parts of the boundary which are in tension, and is calculated using the virtual crack extension technique. The shape derivative of the fracture-resistance objective function is derived. Two il...

observed to confer a high risk for skeletal fracture (Conn 1985; Mathew 1992; Seller 1985). While an association between alcoholism and accidental injury is well recognized (Lucas 1987), there is evidence to suggest that alcoholics may also suffer from a generalized skeletal fragility that makes their bones more liable to fracture. Basic science studies have identified processes that shape bone...

In order to clarify plastic deformation behavior and mechanism of fracture energy absorption Ti3SiC2, Vickers indentation tests were conducted for Ti3SiC2 sintered bodies with various textured orientations. Textured fabricated by slip casting in a strong magnetic field spark plasma sintering (SPS), their orientation distribution analyzed SEM/EBSD. It was found that the around indents such as an...

An experimental study was conducted to examine the room-temperature fatigue crack-growth characteristics of shape-memory NiTi matrix composites reinforced with 10 and 20 vol.% of TiC particles. Microstructural characterization of these hot-isostatically-pressed materials shows that the TiC particles do not react with the NiTi matrix and that they lack any texture. Overall fatigue crack-growth c...

Cohesive zone models are explored in order to study cleavage fracture in adhesive bonded joints. A mode I cohesive model is defined which correlates the tensile traction and the displacement jump (crack faces opening) along the fracture process zone. In order to determine the traction-separation relation, the main fracture parameters, namely the cohesive strength and the fracture energy, as wel...

Hydraulic fracturing is one of the most common methods of well stimulation for reservoirs with low permeability. Hydraulic fracturing increases the flow capacity, alters flow geometry, bypasses damage and improves recovery factor. The pressure of most of Iranian oil reservoirs is declined and consequently the production is reduced. It is necessary to improve the production by using new stimulat...

introduction: this study investigated the fatigue and fracture modes of race and protaper rotary instruments. materials & methods: fatigue resistance was evaluated by rotating the files 30 ° or 60 ° and with 2 or 5mm radius of curvature. race taper 06 size 25 and protaper f1 files (n=40) were used. the number of rotations to failure was analyzed by two-way anova and independent sample     t-tes...