Large Strain Viscoelastic Model for Balloon Film

This paper presents a constitutive model capable of predicting the anisotropic viscoelastic behavior of balloon film subject to large strains and cyclic loading. The model is based on the free volume theory of nonlinear viscoelasticity enhanced with a switching rule for treating loading and unloading differently. The model has been implemented in the finite element analysis program Abaqus/Standard and the results have been compared with experiments on the balloon film StratoFilm 420 under biaxial tension and shear.