Behaviour Of Inflated Structures At MediumPressures

Inflated structures present many interesting properties : they are light, easily folding and present reversible behaviour after failure (they come back to their initial position after unloading). The development of modern textile materials enlarge the possibilities of these objects. Inflation cause tension prestressing in the walls and in the yarns of the structures. This prestressing is proportional to the pressure, and ensure important and quite surprising mechanical strength. Although inflated structures are not recent, no studies have been conducted on this subject at medium or high pressure. The aim of the paper is to present experimental and numerical studies on inflated panels and tubes. They behave as tensioned yarns or wires, but a yarn model gives unacceptable results at medium and high pressure. A beam model cannot be used to calculate the deflection because one cannot link the bending momentum to the curvature , but gives correct results for the limit load. The only way to predict the deflection of an inflated structure is to use numerical modelling. The results obtained by the finite element method are close to the experimental ones.