Finite element analysis of nonlinear transversely isotropic hyperelastic membranes for thermoforming applications

International audienceRecent advances have been made to simulate plastic blow-moulding and thermoforming processes. However, most of the work done is focused on thermoplastic materials assumed to obey an isotropic behaviour. The present paper deals with free and confined inflation of heat-softened fibers-reinforced membranes in order to simulate moulding processes of composite thermoplastic parisons. The material is assumed to be hyperelastic and incompressible. To take into account the anisotropy induced by aligned fibers, the material symmetry class is considered transversely isotropic. A general expression of the strain energy function in terms of tensorial invariants is developed and governing equations of the inflation problem are solved by a total Lagrangian finite element method for space discretization and an explicit finite-difference algorithm for time integration. In order to illustrate our approach, both free and confined inflation examples are examined