A systematic study of crack tip interaction with grain boundaries is critical for improvement of multiscale modeling of microstructurally-sensitive fatigue crack propagation and for the computationally-assisted design of more durable materials. In this study, single, biand large-grain multi-crystal specimens of an aluminum-copper alloy are fabricated, characterized using electron backscattered ...

This study compares adults with and without attention deficit hyperactivity disorder (ADHD) on measures of direct and displaced aggression and illicit drug use. Three hundred ninety-six adults were administered the Wender Utah Rating Scale, the Risk Behavior Assessment, the Aggression Questionnaire (AQ), and the Displaced Aggression Questionnaire (DAQ). Those with ADHD were higher on all scales...

Using Stroh's formalism and conformal mapping, Green's functions are obtained in closed-form for an in®nite thermopiezoelectric plate with an elliptic hole induced by temperature discontinuity. The Green's function satis®es freetraction-charge as well as thermal-insulated conditions along the hole boundary. Based on the Green's function, a system of singular integral equations for the unknown t...

Large scale simulations using cohesive zone interfacial elements were used to understand features such as penetration and deflection of crack during the process of interaction of mode-I crack with inclined interfaces. To perform these simulations, two set of inputs are necessary. The first one is to provide valid loading boundary conditions and the second one is to incorporate accurate cohesive...

the prevalent method of irrigation in paddy fields in iran is continuous ponding, which changes to intermittent method at the time of water shortage. soil cracks are the main problem in intermittent irrigation. in this study, effects of adding rice straw on some soil physical characteristics and cracks were studied in paddy soils of the guilan province of iran. the experiment was performed as s...

Considered is the interaction of macro-and micro-cracks in an anisotropic piezoelectric solid. The GreenÕs function and principle of superposition are used to formulate a system of singular integral equations for solving the unknown temperature discontinuity and elastic displacement-electric potential. The residual heat ̄ux, stress and electric displacement on the microcrack are evaluated direc...

Ultrasonic testing for fatigue crack detection in metallic members are commonly performed using time domain analysis of Rayleigh waves. This approach will be successful only if the fatigue cracks produce strong interaction with the Rayleigh waves. The optimum frequency range of ultrasonic Rayleigh waves for scanning long structural members in the field is from 0.5 to 2.25 MHz because higher fre...

This paper introduces a finite element scheme and a systematic calibration approach for masonry infilled RC frames. The modeling scheme combines the smeared crack approach with discrete crack elements to allow for the opening of diffused flexural and dominant shear cracks. It is, therefore, able to capture the nonlinear material behavior and the interaction of the infill wall with the bounding ...

We calculate elastic moduli and viscosities for media containing strongly interacting in-plane shear cracks. The cracks are randomly oriented or aligned, with equal length or a logarithmic size distribution. Our results from both a boundary element and a finite-element method suggest that the average moduli are best approximated by a differential, self-consistent model (DEM). Thus crack-tocrack...