Analysing Screw Extrusion of Porous Blanks by Methods of Modified Plastisity Theory for Porous Bodies

Abstract

The features of twist-extrusion of porous semi-products containing pores and plain cracks are considered. Influence of cracks on distribution of porosity and local softening was analyzed. Research is carried in framework of the modified plasticity theory of porous bodies. The finite element method was used. It was found that porosity fields as well as the accumulated plastic strain are sensitive to concentration of plain defects. It was shown the specialties of porosity fields defined by cracks concentration: it is more in a center than its value on periphery. Influence of plain defects on the accumulated strain leads to opposite result. The use of contrpressure is able to suppress the growth of defects, a few reducing.