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Optimized upper bound analysis of polymer coated metal rod extrusion through conical dieShah, Ritesh Lalit 17 September 2007 (has links)
Extrusion is a metal forming process used extensively in industry to produce different
structural, mechanical, electrical, architectural, automotive and aerospace application
parts. Currently after extrusion, the rod is subjected to environmental wear due to long
storage time and hence requires an additional cleaning process before further use. This
cleaning process can be eliminated by extruding a polymer coated metal rod workpiece
such that the polymer coating is sustained on the final product after the extrusion
process.
In the present research study a new upper bound analytical model is developed to predict
the forces required to conduct extrusion of a polymer coated metal rod successfully. The
search for the lower upper bound power functional is modeled as a non linear
optimization problem. Optimizing the functional also determines the set of constraints
defining the shape of rigid plastic deformation boundaries and the final coating
thickness. Also an upper bound analytical model was developed to predict forces for
failure of the polymer coating during the extrusion. Both the analytical models for successful and failed extrusion are compared to obtain critical die angle which can
provide tooling and process design guidelines. Finite element analysis simulations were
modeled using commercially available software package, ABAQUS. Predictions of FEA
simulations were in good agreement with published results and with the predictions of
analytical model developed in this study.
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Process structuring of polymers by solid phase orientation processingCoates, Philip D., Caton-Rose, Philip D., Ward, Ian M., Thompson, Glen P. January 2013 (has links)
No / Solid phase orientation of polymers is one of the most successful routes to enhancement of polymer properties. It unlocks the potential of molecular orientation for the achievement of a range of enhanced physical properties. We provide here an overview of techniques developed in our laboratories for structuring polymers by solid phase orientation processing routes, with a particular focus on die drawing, which have allowed control of significant enhancements of a single property or combinations of properties, including Young's modulus, strength, and density. These have led to notable commercial exploitations, and examples of load bearing low density materials and shape memory materials are discussed.
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