Finite element analysis of the thermoforming manufacturing process using the hyperelastic Mooney-Rivlin model

Abstract

Thermoforming is a manufacturing process widely used to produce thin thermoplastic parts. In this process a previously extruded thermoplastic sheet is clamped and then heated and formed into a mold cavity using a differential pressure. In this paper a finite element model of the thermoforming process of an ABS sheet is proposed and numerical results are compared to data from literature. Thermoplastic sheet is modelled according to the membrane formulation. An implicit time scheme has been adopted for the integration algorithm, Mechanical behaviour of the processing material is assumed as hyperelastic, according to the two parameters Mooney-Rivlin model. Mathematical formulation of the mechanical model is exposed. The proposed model allows to evaluate material thinning, stresses, strains and contact status between the processing material and the die. © Springer-Verlag Berlin Heidelberg 2006.