Modélisation des assemblages de ballons pressurisés stratosphériques

Abstract

Long duration super-pressure balloon design and manufacturing is a great challenge for the CNES in scientific ballooning. They are made of 50 µm thick polymer films (PET/PA/PET) which are joined with 23 µm thick adhesive PET bands. To date, during flight missions, a real problem appears: some balloons explode prematurely. This is why this study deals with the mechanical behaviour of the stratospheric pressurized balloons and particularly with the assembly of the constitutive materials. Firstly, a nanoindentation test campaign makes it possible to identify the elastic properties of the materials directly in the assembly at two different temperatures. Then, we simulate a nominal assembly in two approaches: 2D and 3D. More particularly, we present an example concerning a defect of the junction in 3D approach using the submodeling technique. Finally, we use the factorial design method at two levels and finite-element models to study the influence of the various conception parameters on the mechanical behaviour of the assembly.