Failure of Polyethylene Thin Film Membrane Structures

The failure of balloons made of Linear Low Density PolyEthylene (LLDPE) is investigated. The chosen film is 38 μm thick StratoFilm 420, currently used for the NASA Super-Pressure balloons [1]. The visco-elastic behaviour of the film has been extensively studied and is already accounted for in the balloon design [2, 3, 5]. The next step in the development of accurate predictive tools for super-pressure balloons requires models that capture the transition from visco-elastic and visco-plastic behaviour to fracture. It is shown that realistic estimates of failure of LLDPE membrane structures can be obtained from visco-elastic simulations based on the non-linear visco-elastic model of the balloon film proposed by Kwok [5], supplemented with a fracture resistance criterion derived from the experimentally-based J-integral