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...

An asymptotic description of the acoustic signature of a crack, breaking the surface of an otherwise homogeneous, isotropic elastic material, determined using either a line focus or a point focus scanning acoustic microscope is constructed. The incident focused beam is constructed as a Fourier integral that produces a specified profile in the focal plane. The wavefields scattered from the speci...

The problem of fatigue-crack-growth in a rotating disc at different crack orientation angles is studied by using an automated numerical technique, which calculates the stress intensity factors on the crack front through the three-dimensional finite element method. Paris law is used to develop the fatigue shape of initially semi-elliptical surface crack. Because of needs for the higher mesh dens...

We present a motion-based method to extract the multiple 3D crack surfaces from a sequence of 3D X-ray microtomographic mortar images. We verify the correctness and accuracy of results by ground truth obtained with simulated cracks in real specimens. We provide several three-dimensional measures of crack surface, including the number of cracks, surface area, volume, tortuosity, and permeability.

The detection, location, and sizing of a fatigue crack emanating from a fastener hole in an aluminum plate is investigated. Two linear arrays of surface mounted piezoelectric disk transducers send and receive ultrasonic guided waves that are transmitted, reflected, and scattered by both the joint geometry and the fatigue crack. A tomography algorithm is used to detect and locate the crack. Ampl...

Precracked and notched specimens were used to investigate the fracture mechanism of a bainite steel at low temperature. The critical fracture event was studied using metallographic sectioning method. The results showed that the critical cleavage event was different in the precracked and the notched specimens. At -196C, all specimens fractured at lower-shelf region without any ductile crack grow...

The use of microwave technique has proved to be a viable means for crack detection and sizing surface cracks in metals. In this technique, the surface of the specimen is interrogated with a radiating open-ended waveguide probe and a crack is assumed to be a simple short-circuited rectangular waveguide, causing peturbations in the probe reflection coefficient. Since the growth of fatigue in meta...

Nondestructive testing of concrete allows the inspection of larger areas of concrete members at lesser cost than coring and provides more information than visual inspection. This paper addresses a new approach for determining the positions and size of cracks in concrete members by using ultrasonic pulse velocity test. Three plain concrete beams, containing artificial cracks (30 – 60% of the bea...

A solution is given for the elastic stress field in a half plane containing a plane crack parallel to the surface and subjected to a uniform normal pressure and a concentrated normal load. Frictional slip according to Coulomb's law is permitted between the crack faces. As the load is increased, a slip zone originates and grows either from a crack tip or from an intermediate point. Various arran...