On rational representation of constitutive equations to solve plastic forming problems

Continuous improvement of requirements to the accuracy of plastic forming process calculations puts on agenda an enhancement in the accuracy of description of stress-strain constitutive equations. An elastic deformation of material is traditionally described by Hooke' law, while a plastic one by bilinear models of plastic deformation or nonlinear exponential law of plastic strain hardening. The article analyses the potential and points out advantages of application of non-uniform, rational B-splines (NURBS) to make more accurate representation of material behaviour under elastic-plastic deformation.