INFLUENCE OF MATERIAL PROPERTIES ON SOLID-PHASE FORMING BEHAVIOR OF POLYMERS

Abstract

In this paper the general-purpose Finite Element code, ABAQUS, with a plane stress solution has been employed to analyse the solid phase forming behaviour of polymers. A new approach is developed in which types of uniaxial stress-strain behaviour have been considered as materials property data for finite element analyses. They were chosen to demonstrate the influence of work hardening and cold working on the deformation process. Plane stress finite element analyses were carried out for the various cases plus the experimentally determined stress-strain retationship for the polypropylene material. Deformed shape, axial strain and shear strain data were obtained and work hardening and cold drawing influences on the deformation process were analysed. The results showed that the earlier the cold drawing process and the higher the rate, the smoother the neck and the more gradual the neck propagation process. Furthermore, it was shown that the lower the work hardenability of the material, the sharper the neck and the greater the difficulty in propagating the neck into the shoulder area of the sample. It is concluded that the new approach (using model stress-strain relationships) is effective in studying polymer deformation processes. Furthermore, it is suggested that this approach can be used to develop a constitutive model equation for the deformation of polymers and to design new polymers for specific applications or products.