An analysis is presented of the process of die drawing isotropic polymers, in the form of circular rods, to produce highly oriented materials with enhanced mechanical properties. The stresses in a small element of material undergoing the drawing process have been analyzed using a force‐equilibrium approach and the initial yield and flow stresses in the material have been predicted from the von‐Mises yield criterion. The stress‐strain‐strain rate characteristics of the polymer used in the analysis were deduced from uniaxial tensile test data obtained at the same temperature at which the die drawing occurred. Experimental results are presented of the stress in polypropylene GSE‐108 rods when die drawn at 90°C in a purpose‐built die drawing facility. Novel techniques were used to determine the stress and strain distributions along the die. A comparison of the experimental results and the analytical predictions shows good agreement.

No abstract

No abstract

The model work presented in this paper was stimulated by investigations carried out on 3.7m diameter horizontal cylindrical vessels used as oily water separators. In these, internal diaphragms were installed to provide support for the horizontal sand filter bed running the full length of the vessel. By means of four cylindrical plastic models two different designs for the diaphragm are considered. On the basis of strain gauge investigations, conclusions are drawn which should provide a design approach for these components whereby certain peak stresses can be avoided.