MECHANICAL CHARACTERIZATION AND SIMULATION UNDER MULTIAXIAL CONDITIONS OF POLYHYDROXYALKANOATES

This study focuses on the mechanical properties characterization of biodegradable and bio-based materials: the Polyhydroxyalkanoates (PHAs). An original experimental set-up has been developed to perform multiaxial tests on a single shape of cylindrical specimen. It is composed of a load cell and a mechanical assembly allowing successive or simultaneous loading cycles of tensile, compression and torsion. Classical shear and tensile tests, besides the fact they use different specimen shapes, seems not sufficient to get a suitable 3D constitutive model. The aim is so to perform complex loading paths with direction changing and cycles during a test, allowing to scan all the deviatoric plan of deformation and taking into account the loading history. This database is used for the identification of an Hyperelasto- Visco-Hysteresis (HVH) model which is used to simulate the mechanical behavior of food packaging structure in PHAs.