Continuum models, based upon both the Volterra and the Peierls descriptions of a screw dislocation ahead of a mode III crack, are used to evaluate the critical loading for dislocation nucleation at the tip of a ® nite pre-blunted crack. Results are presented for various crack tip root radii, for several crack lengths. Moreover, the e€ ect of ledge formation at the crack tip is evaluated. It is ...

A finite element simulation framework for cutting and fracturing model without remeshing is presented. The main idea of proposed method is adding a discontinuous function for the standard approximation to account for the crack. A feasible technique is adopted for dealing with multiple cracks and intersecting cracks. Several involved problems including extended freedoms of finite element nodes a...

PURPOSE The aims of the present study were to compare the image quality and visibility of tooth cracks between conventional methods and swept-source optical coherence tomography (SS-OCT) and to develop an automatic detection technique for tooth cracks by SS-OCT imaging. METHODS We evaluated SS-OCT with a near-infrared wavelength centered at 1,310 nm over a spectral bandwidth of 100 nm at a ra...

We discuss here several results on the convergence of finite element methods for problems with corners and cracks. We also derive some a priori estimates for a certain class of hybrid finite elements.

The initiation and growth behavior of short fatigue cracks from the interfacial micro-notches in a SCS-6/Ti composite at various maximum applied stress levels were quantitatively characterized. Micro-notches in the interfacial reaction layer were induced by applying monotonic tensile loading prior to fatigue testing. The propagation and arrest behaviors of each individual crack were carefully m...

Lasers provide a non-contact and remote inspection method with high resolution and sensitivity. As a crack detection tool, laser ultrasonics can be used to image surface-breaking cracks with microscopic precision. By monitoring the local elastic scattering conditions and dynamic motion fields present in the immediate vicinity of a surface-breaking crack site, the local crack morphology can be m...

A scheme for the numerical solution of singular integral equations on piecewise smooth curves is presented. It relies on several techniques: reduction, Nyström discretization, composite quadrature, recursive compressed inverse preconditioning, and multipole acceleration. The scheme is fast and stable. Its computational cost grows roughly logarithmically with the precision sought and linearly wi...

Although much has been learned about the elastic properties of solids with cracks, virtually all the work has been confined to the case when the cracks are stationary, that is, neither grow nor shorten during loading. In that case, the elastic moduli obtained are the secant moduli. The paper deals with the practically much more important but more difficult case of tangential moduli for incremen...

Abstract: Thermal fatigue is a stochastic process often showing considerable scatter even in controlled environments. Due to complexity of thermal fatigue, there is no a complete analytical solution for predicting the effect of this property on the life of various components, subjected to severe thermal fluctuations. Among these components, one can mention car cylinder, cylinder head and pi...

The finite element alternating method is an attractive and efficient method for calculating the stress intensity factor of cracks emanating from fastener holes such as the problem of multiple site damage (MSD) at the fuselage skin of aging aircraft. While the alternating method has been used to solve various engineering problems in assessing the structural integrity of aging aircraft, this meth...