This paper presents a numerical investigation using the two-parameter fracture mechanics approach for studying threaded fastener geometries. It was found that the constraint arising from the presence of a surface crack in a threaded fastener does influence the stress in the forward sector. Consequently, the actual stress field shows a deviation from the theoretical HRR solution. Implementation ...

A methodology is evaluated to predict the probability of specimen failure with subsequent fatigue, after a short surface crack has been detected in Al 2219-T851 alloy. Cracks are detected and tracked to failure using optical microscopy. Predictions of remaining lifetime distributions are made with a i~onte Carlo procedure in conjunction with growth laws which model the effect of grains of diffe...

In this paper, we deal with the acoustic inverse scattering problem for reconstructing complex cracks from the far field map. The scattering problem models the diffraction of waves by thin two-sided cylindrical screens. A complex crack is characterized by its shape, the type of boundary conditions and the boundary coefficients (surface impedance). We give explicit formulas which can be used to ...

In some applications such as quality control of metal components or inspection of large metal structures, inspection systems with rapid scanning capability are required. Of particular interest are systems capable of real-time detection and sizing of surface breaking cracks in metals. Since such systems have to perform the data processing in the course of scanning, they should be based on NDE te...

In this paper we address the issue of a creeping wave by investigating a twodimensional configuration which involves a surface-braking crack in a traction free planar backwall. We assume that this back-wall is irradiated by a shear Gaussian beam which is incident at a critical angle and hits the wall away from the crack edge. We show that the generated wave known in the engineering literature a...

Fatigue crack propagation in 3Y-TZP was investigated using controlled surface flaws. A unique growth law strongly dependent on the maximum stress intensity factor and quadratically dependent on the amplitude of the range of stress intensity factor was established. This growth law was found to apply for both surface flaws and internal flaws and could be used to predict fatigue lifetime. The pres...

Long-term durability is a major obstacle limiting the widespread use of lithium-ion batteries in heavy-duty applications and others demanding extended lifetime. As one of the root causes of the degradation of battery performance, the electrode failure mechanisms are still unknown. In this paper, we reveal the fundamental fracture mechanisms of single-crystal silicon electrodes over extended lit...

The resonance phenomenon observed in Rayleigh wave scattering from surface-breaking cracks has been investigated using Freund's results on reflection of Rayleigh waves from an infinite crack edge. To model the crack as a section of acoustic waveguide, resonances are treated as standing waves in the length and depth directions. The model takes both faces of the crack into consideration, and this...

Sol–gel Ru0.3Sn0.7O2 electrode coatings with crack-free and mud-crack surface morphology deposited onto a Ti-substrate are prepared for a comparative investigation of the microstructural effect on the electrochemical activity for Cl2 production and the Cl2 bubble evolution behaviour. For comparison, a state-of-the-art mud-crack commercial Ru0.3Ti0.7O2 coating is used. The compact coating is pot...

This paper considers a 2-D fracture analysis of anisotropic piezoelectric solids by a boundary elementfree method. A traction boundary integral equation (BIE) that only involves the singular terms of order 1/r is first derived using integration by parts. New variables, namely, the tangential derivative of the extended displacement (the extended displacement density) for the general boundary and...