OBJECTIVES Presentation of a methodological approach using stereo and scanning electron microscope examination for the failure analysis of an alumina all-ceramic premolar crown (Procera AllCeram). METHODS The recovered part of a fractured Procera alumina crown was examined utilizing first a stereomicroscope and second a scanning electron microscope (SEM). The stereomicroscope analysis was per...

Texturing the surface of a PDMS fi lm with microscale pillars has been shown to enhance shear adhesion to a rigid substrate by an order of magnitude when compared to untextured control fi lms. In this study, it is shown that shear load is distributed uniformly among the contacts rather than concentrated on the contacts nearest the edge of the fi lm-substrate interface, which is in contrast to t...

In earlier work we developed inductive coupling for surface-mounted Lamb wave transducers operating at relatively low frequencies, such as 300 kHz. We now report on similar inductively-coupled transducers at higher (multiple MHz) frequencies. Our investigation was motivated by a particular application, to examine a box girder top flange, using transducers mounted along the flange edge. We emplo...

Some recent experimental observations of highly dynamic crack growth events in thick unidirectional graphite fiber-reinforced epoxy matrix composite plates are presented. The composite plates were symmetrically (mode-I) and asymmetrically (mode-II) loaded in a one-point bend configuration with an edge pre-notch machined in the fiber direction. The lateral shearing interferometric technique of c...

One of the crucial steps in the shaft design process is the optimal selection of the material. Two types of shaft steels with improved corrosion resistances, 1.4305 and 1.7225, were investigated experimentally and numerically in this paper in order to determine some of the material characteristics important for material selection in the engineering design process. Ultimate tensile strength and ...

Lamb modes are widely used for non-destructive evaluation of plate-like structures and simple interpretation procedures for the analysis of the monitored structures are needed. In this study we apply the orthogonality relation based method for post-processing Finite Element (FE) predictions in order to separate Lamb modes at a plate edge. The reflected wave field from the free edge is a superpo...

This paper presents responses of an edge circular cantilever beam under the effect of an impact force. The beam is excited by a transverse triangular force impulse modulated by a harmonic motion. The Kelvin-Voigt model for the material of the beam is used. The cracked beam is modelled as an assembly of two sub-beams connected through a massless elastic rotational spring. The considered problem ...

methodologies to calculate failure probability and to estimate the reliability of fatigue loaded structures are developed. The applicability of the methodologies is evaluated with the help of the fatigue crack growth models suggested by Paris and Walker. The probability theories such as the FORM (first order reliability method), the SORM (second order reliability method) and the MCS (Monte Carl...

Several previous studies have demonstrated the importance of constituent inclusion particle distributions on variability in observed fatigue lifetimes. Such models have often concentrated on crack growth behavior in standard test specimens such as single edge notch tension (SENT) geometries. The methodology used here is similar to others in that constituent particles sizes were modelled as init...

This letter is concerned with an interfacial edge crack in a piezoelectric bimaterial wedge interacting with a screw dislocation under antiplane mechanical and in-plane electric loading. In addition to a discontinuous electric potential across the slip plane, the dislocation is subjected to a line-force and a line-charge at the tip. The out-of-plane displacement and electric potentials are obta...