Salim N A A M A N Naaman | National Institute of Industrial Engineering(NITIE) (original) (raw)

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Papers by Salim N A A M A N Naaman

Salim Naaman , 2019

It a real Kenyan certificate of the national industrial training authority to the country.

Gradient Continuum Modeling DTU Orbit (31/12/2018) Micro-Structural Evolution and Size-Effects in... more Gradient Continuum Modeling DTU Orbit (31/12/2018) Micro-Structural Evolution and Size-Effects in Plastically Deformed Single Crystals: Strain Gradient Continuum Modeling An extensive amount of research has been devoted to the development of micro-mechanics based gradient plasticity continuum theories, which are necessary for modeling micron-scale plasticity when large spatial gradients of plastic strain appear. While many models have proven successful in capturing the macroscopic effects related to strain gradients, most predict smooth micro-structures. The evolution of dislocation micro-structures, during plastic straining of ductile crystalline materials, is highly complex and nonuniform. Published experimental measurements on deformed metal crystals show distinct pattern formation, in which dislocations, of the geometrically necessary kind, are arranged in wall and cell structures. This particular subset of signed dislocations, which have a net Burg-ers vector, are the main sour...

Archive of Applied Mechanics, 2019

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Mechanics of Materials, 2019

International Journal of Plasticity, 2016

European Journal of Mechanics - A/Solids, 2013

Cracked ductile sheet metals, subject to Mode I tearing, have been observed to display a variety ... more Cracked ductile sheet metals, subject to Mode I tearing, have been observed to display a variety of fracture surface morphologies depending on the material properties, and a range of studies on the fracture surface appearance have been published in the literature. Whereas classical fractures such as cup-cone, cupecup and slanting are widely observed, the phenomenon of a slanted crack which systematically "flips" back and forth in a roughly 45 orientation has only recently been reported. The present study aims to add details and understanding to this crack growth phenomenon e through experimental testing and comparison with published results. A series of crack propagation tests have been carried out, where cracks are driven many plate thicknesses under global Mode I loading. The current study employs both the edge crack specimen (ECS) loaded in combined in-plane bending and extension, and the double edge notched tension (DENT) specimen loaded in extension. Clear evidence of the alternating slant failure is observed for a normal strength steel and details on the phenomenon are brought out by grinding and polishing crosssections in successive steps along the crack growth direction. Moreover, these results are compared to a soft aluminum (1050A) which predominantly shows cupecup or slant failure. In general, both materials fail by the mechanism of void growth to coalescence (fractographs are included), and evidence points toward cupecup being favored by materials that experience extensive amounts of void growth (thus severe thinning in the process zone), whereas slanting is typical in high strength materials that rapidly nucleate large populations of smaller voids.