Numerical Simulation Of An Elastomer In A Metalforming Process

Abstract

The use of elastomers as pressure media in the tube hydroforming technology has received increasing interest especially for the production of lightweight and complicated forming components, because of uniform pressure application that confers more ductility to the pieces being conformed. In order to understand how the different parameters, such as the hardness of the components and the intensity of the applied loads on the blankhold, interact in the forming process, it is essential to define the elastomer behavior accurately. This is the focus of the present work. The behavior of the elastomer is characterized by high deformability, nonlinear stressstrain response, damping, rate independent hysteresis and quasiincompressibility. Within the framework of continuum thermodynamics of irreversible processes with internal variables and large strains, the formulation of a phenomenological constitutive law is presented. A viscohyperelastic model with associated plasticity in finite strains, the algorithm for its numerical integration, and its implementation in an explicit dynamic finite element code are described. Application examples related to a product of cosmetic industry are analysed, together with the influence of different parameters in the forming process.