An important task in mixed-mode fracture analysis and prediction is the simulation of crack growth under mixed-mode conditions. To complete such a task, one must have (a) a computer code capable of handling the kinematics of general crack growth and determining the stress and deformation states during crack growth, and (b) a fracture criterion that can properly predict the instant and direction...

Advances in tetrahedral mesh generation for general, three-dimensional domains with and without cracks are described and validated through extensive studies using a wide range of global geometries and local crack shapes. Automated methods are described for (a) implementing geometrical measures in the vicinity of the crack to identify irregularities and to improve mesh quality and (b) robust nod...

X-Ray Diffraction Contrast Tomography (DCT) is a recently developed, non-destructive synchrotron imaging technique which characterizes microstructure and grain orientation in polycrystalline materials in three dimensions (3D). By combining it with propagation based Phase Contrast Tomography (PCT) it is possible to get a full picture description for the analysis of local crack growth rate of sho...

THE SELF STRESS field and self energy are estimated for a planar 3D dislocation loop emanating from a halfplane crack tip. While the problem is of greatest interest for analysis of shear loops nucleating from the crack tip in the concentrated stress field there due to applied loadings, it is addressed here in the interest of tractability for 3D prismatic loops lying in the same plane as the cra...

Critical steps toward designing and developing modern materials include observing, simulating, and predicting 3D deformation and cracking mechanisms at various length scales. In this work, advanced characterization and simulation techniques are employed to study the micromechanisms involved in nucleation and propagation of fatigue cracks in an aluminum alloy used in pressure-vessel structures. ...

A set of Shock Wave Lithotripsy(SWL) related experimental observations including 3D dynamic crack propagation, reported in literature, are simulated with the aim of understanding the fragmentation of kidney stone with SWL. Extracorporeal shock wave lithotripsy (ESWL) is the fragmentation of kidney stones by focusing an ultrasonic pressure pulse onto the stones. 3D models with fine discretizatio...

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.

We have performed massively parallel 3D molecular dynamics simulations with up to 35 million atoms to investigate ductile fracture. We have obtained mechanistic information at the atomistic level inaccessible to experiment. We observe dislocation loops emitted from the crack front|the rst time this has been seen in computer simulations. The sequence of dislocation emission (crack blunting proce...

* Corresponding author; Email: [email protected] ABSTRACT An important task in mixed-mode fracture analysis and prediction is the simulation of crack growth under mixed-mode conditions. To complete such a task, one must have (a) a computer code capable of handling the kinematics of general crack growth and determining the stress and deformation states during crack growth, and (b) a fracture crit...

In the present paper, stress intensity factor (SIF) analyses and fatigue-crack-growth simulations of corner cracks emanating from loaded pinholes of attachment lugs in structural assemblies are carried out for different load cases. A three-dimensional (3D) symmetric Galerkin boundary-element method (SGBEM) and FEM alternating method is developed to analyze the nonplanar growth of these surface ...