For a crack impinging upon a bimaterial interface at an angle, the singular stress field is a linear superposition of two modes, usually of unequal exponents, either a pair of complex conjugates, or two unequal real numbers. In the latter case, a stronger and a weaker singularity coexist (known as split singularities). We define a dimensionless parameter, called the local mode mixity, to charac...

Delamination is a critical form of failure in composite laminates which is partitioned into a combination of three pure modes namely; opening, shearing and tearing (modes I, II and III respectively). Each fracture mode contributes to the total energy required for delamination growth, due to a combination of the different damage mechanisms that occur under each mode 1-2 . To formulate reliable m...

INTRODUCTION This study investigated the fatigue and fracture modes of RaCe and ProTaper rotary instruments. MATERIALS AND 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-test. F...

As the major field in petroleum reserve growth, fractured-vuggy reservoir is the key research in the future. However, in the development of fracture-cavity reservoir, collapse may occur in karst cave which greatly affects the oil well output. In order to forecast the cave collapse before drilling, this work adopts the method of span dichotomy reduction to determine the critical karst collapse o...

The deflection and fracture of metal sandwich plates subjected to intense uniform impulsive pressure loads are studied for plates made of four steels representing a wide range of strength, strain hardening and ductility. Sandwich plates with both square honeycomb cores and folded plate cores are considered. The primary fracture modes of the sandwich plates are necking and subsequent tearing of ...

We present a continuum phase-field model of crack propagation. It includes a phase-field that is proportional to the mass density and a displacement field that is governed by linear elastic theory. Generic macroscopic crack growth laws emerge naturally from this model. In contrast to classical continuum fracture mechanics simulations, our model avoids numerical front tracking. The added phase-f...

OBJECTIVES First to compare different dentin bonding agents' shear bond strength to primary and permanent dentin. Secondly to compare the fracture failure modes and making an attempt to develop a statistical model that could be helpful in predicting them. METHODS Extracted human primary and permanent molars were used as substrates (dentin). The shear bond strength of composite to substrate wa...

BACKGROUND The number of elderly patients with maxillofacial trauma is rapidly increasing due to active lifestyles and longevity. Shimane prefecture has the fastest growing proportion of elderly individuals in Japan. The aim of this study was to reveal the distinctive features and treatment modes of mandibular fracture treatment mode in patients requiring hospitalization at the Department of Or...

To investigate the influence of post length and amount of remaining root tissue on the fracture resistance of roots restored with fibre posts relined with resin composite. Ninety upper canine teeth were divided into nine groups (n = 10). The post spaces were prepared resulting in different lengths, as follows: group 2/3, preparations with lengths of 10 mm; group 1/2, preparations with lengths o...