Flaws in material, appearing because of imperfections, manufacturing faults or severe service conditions, can easily threaten the structural integrity of engineering components. This is particularly dangerous when concerning equipment whose purpose is to protect larger systems, e.g. pressure safety valves (PSV) that protect pressure vessels and equipment of overpressure. Catastrophic consequenc...

An integrated manufacturing process simulation framework has been developed to predict the trimmed edge tensile stretchability of AA6111-T4 sheets by incorporating the burr geometry, damage, and plastic strain from trimming simulations into subsequent tensile stretchability simulations. The influence of the trimming die clearances on the predicted tensile stretching ductility (stretchability) i...

A continuum model based upon the Peierls-Nabarro description of a dislocation ahead of a crack is used to evaluate the critical mode I loading for dislocation nucleation at the tip of a finite, pre-blunted crack. A similar approach is used to evaluate the critical mode I loading for atomic decohesion. Results are presented for various crack tip root radii (a measure of bluntness), for several c...

Edge-notched eccentrically compressed fracture specimens made of aggregate of reduced size are loaded in standard creep test frames. Measurements of the time rate of crack mouth opening in notched concrete specimens subjected to constant load of almost one month duration are reported and analyzed. To reveal the size effect, geometrically similar specimens of four sizes in the ratio I :2:4:8 are...

Pangolin scales form a durable armor whose hierarchical structure offers an avenue towards high performance bio-inspired materials design. In this study, the fracture resistance of African pangolin scales is examined using single edge crack three-point bend fracture testing in order to understand toughening mechanisms arising from the structures of natural mammalian armors. In these mechanical ...

Strain-rate effects on fracture behavior of unidirectional composite materials are studied. Single-edge notched multi-layered unidirectional graphite composites (T800/3900-2) are investigated to examine fracture responses under static and dynamic loading conditions using a digital speckle correlation method. The fracture parameters for growing cracks are extracted as a function of fiber orienta...

1 Assistant Professor, Department of Mechanical and Aeronautical Engineering; Graduate student, Professor and Professor, respectively, Department of Chemical Engineering and Materials Science, University of California, One Shields Avenue, Davis, CA 95616. 2 Assistant Professor, Department of Civil and Environmental Engineering, University of Illinois, Urbana IL 61801-2352. Abstract: This paper ...

The aim of this study is to evaluate the microstructures, tensile lap shear strength, and fatigue resistance of 6022-T43 aluminum alloy joints welded via a solid-state welding technique-ultrasonic spot welding (USW)-at different energy levels. An ultra-fine necklace-like equiaxed grain structure is observed along the weld line due to the occurrence of dynamic crystallization, with smaller grain...

The feasibility of predicting the fracture behavior of surface cracks from shallow cracked bend specimens was investigated. The material studied was a high-strength steel stress relief embrittled to various levels of Charpy-V notch impact toughness. Material toughness was quantified in terms of the J-intergral at total specimen failure (-/„,,), using both deeply notched and shallow-notched bend...