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Structures composed of metallic-composites suggest a combination of mechanical and physical properties for a wide variety of industrial applications. In comparison with homogeneous materials there are distinct advantages to multi-layered materials in the field of nuclear engineering, chemical as well as in cryogenic engineering and aeronautical technologies. Some of the methods that such composite structures are produced are done by plastic forming processes. In these processes there are sometimes defects in that include: bulging, choking dead zones, residual chips, chevroning, formation of "fish skin" cracks. In this work an analysis of the radial stress and velocity fields is performed according to the J2 flow theory for a constitutive model of rigid/perfectly plastic material. The main outcome of this work is the derived validity limits of the radial solutions This research touches and exposes a wide range of relevant issues: generalization of the solutions of converging radial flows for homogeneous material to materials with general transverse non-homogeneity and defining the "safe" range of configurations parameters in which flawless processes can be achieved.

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Gal G. Davidi, B.Sc, M.Sc., Ph.D: studied at Technion - Israel institute of technology, Israel. CEO at CFD FEM Engineering Consulting, Israel. Specializes in structural analysis as well as fluid dynamic computation.

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