due to the algorithmic simplicity, cellular automata (ca) models are useful and simple methods in structural optimization. in this paper, a cellular-automaton-based algorithm is presented for simultaneous shape and topology optimization of continuum structures, using five-step optimization procedure. two objective functions are considered and the optimization process is converted to the single ...

This study uses a torsional split-Hopkinson bar to investigate the shear response and fracture characteristics of unweldable Al-Sc alloy during mechanical testing at shear strain rates of 800 s , 1500 s , 2200 s 1 and 2800 s 1 and temperatures of 150 C, 25 C and 300 C. The experimental results show that both the shear strain rate and the temperature have a significant effect on the shear proper...

Ah&act-Steady state thermomechanical deformations of a thick viscoplastic target being penetrated by a fast moving long rigid cylindrical penetrator are analysed by the finite element method. Two different constitutive relations, the Bodner-Partom flow rule, and the Litonski-Batra flow rule, are used to model the viscoplastic response of the material. The two flow rules are calibrated to give e...

Once plaques intrude into the lumen, the shear stress they are exposed to alters with hitherto unknown consequences for plaque composition. We investigated the relationship between shear stress and strain, a marker for plaque composition, in human coronary arteries. We imaged 31 plaques in coronary arteries with angiography and intravascular ultrasound. Computational fluid dynamics was used to ...

prised of highly deformed droplets. Such emulsions exhibit We have measured the yield transition of monodisperse emula plastic-like response to shear deformations; for small deforsions as the volume fraction, f, and droplet radius, a , are varied. mations, they resist the shear elastically, with the stress, t, We study the crossover from the perturbative shear regime, which being linearly propo...

A comprehensive three-dimensional (3-D) shape-based approach for quantification of regional myocardial deformations was evaluated in a canine model (n = 8 dogs) with the use of cine magnetic resonance imaging. The shape of the endocardial and epicardial surfaces was used to track the 3-D trajectories of a dense field of points over the cardiac cycle. The shape-based surface displacements are in...

The following nomenclature is used in this Chapter: a allotriomorphic ferrite aa acicular ferrite a w Widmanstatten ferrite ~ delta-ferrite !:i.0' increment in yield stress I austenite € true strain € true average strain €~ true plastic strain in softer phase of a dual-phase steel €~I true plastic strain in harder phase of a dual-phase steel €UTS true strain at ultimate tensile stress €y true s...

In this article, stress analysis and energy estimation during cold-roll forming of symmetrical channel sections have been discussed. Geometry of sheet strip is pre-estimated by a shape function. Then longitudinal, transversal and shear strains have been calculated. Using both the Levy-Mises and the Prandtl Reuss equations, and also considering the Bauschinger effect, stress distributions have b...

The modern engineering structures require the advanced engineering materials to resist the high temperatures and to provide high stiffness. In particular the functionally graded porous materials (FGPMs) introduced are expected to have these desired properties, consequently eliminating local stress concentration and de-lamination. In the present paper, a new shear strains shape function is chose...