STATEMENT OF PROBLEM Bonded porcelain veneers are widely used esthetic restorations. High success and survival rates have been reported, but failures do occur. Fractures are the commonest failure mode. Minimally invasive or thin veneers have gained popularity. Increased enamel and porcelain thickness improve the strength of veneers bonded to enamel, but less is known about dentin or mixed subst...

This paper deals with the basic mechanisms of fatigue damage in materials exposed to service and a series of nondestructive techniques for the early detection of this damage. For all materials with reasonably high fracture toughness it is the organized motion of dislocations that either forms extrusions/intrusions (surface roughness) or the piling up of dislocations at grain boundaries or inter...

This paper investigates the phenomenon of slant fracture observed in stable tearing tests of many ductile materials, where an initially flat crack, loaded under remote Mode I conditions, tends to grow into a slant crack and stay in the slant configuration until final fracture. In an effort to identify potential reasons why cracks prefer to grow in a slant manner, three-dimensional finite elemen...

To obtain a high-quality Al/steel dissimilar joint, micro-groove-assisted vortex-friction stir lap welding (MG-VFSLW) process was developed. Through prefabricating micro-grooves on the steel plate surface by laser ablation, mechanical interlock and metallurgical bonding were obtained simultaneously in MG-VFSLW process. The weld formation, interface microstructure, properties, failure mode studi...

A very important problem in the research of layer structures is modeling cracks on material interface. Due to complex physical and mechanical properties this structure, simulation discontinuities such as interface by traditional finite element methods requires a fine mesh density. Furthermore, smoothing really large amount computational resources. Therefore, extended algorithm which does not re...

In order to achieve a high-quality joining of aluminum (Al) and copper (Cu) dissimilar metals, new friction stir double-riveting welding (FSDRW) with Cu rod as the rivet was proposed, rotating tool large concave angle shoulder specially designed. The results showed that under thermal–mechanical effect tool, deformed be double riveting heads structure anchor at upper surface Al plate an above la...

A image processing algorithm was developed for detecting stress cracks in corn kernels using a commercial vision system. White light in back-lighting mode with black-coated background having a small aperture for the light provided the best viewing conditions. The kernel images, when processed using the algorithm developed, produced white streaks corresponding to the stress cracks. Double stress...

An analysis is presented for transient response of a mode-III interfacial crack propagating between two dissimilar piezoelectric half spaces. The dynamic fracture toughness of a piezoelectric interface is examined, which is a central issue related to the interface strength of multi-layered sensors and ferroelectric thin film devices. For the mode-III crack propagation in piezoelectric materials...