An inflatable fabric beam finite element

Abstract

International audienceInflatable structures made of modern textile materials with important mechanical characteristics can be inflated at high pressure (up to several hundreds kPa). For such values of the pressure they have a strong mechanical strength. The aim of the paper is to construct a new inflatable beam finite element able to predict the behaviour of inflatable structures made of beam elements. Experiments and analytical studies on inflatable fabric beams at high pressure have shown that their compliance is the sum of the beam compliance and of the yarn compliance. This new finite element is therefore obtained by the equilibrium finite element method and is modified into a displacement finite element. The stiffness matrix takes into account the inflation pressure. Comparisons between experimental and numerical results are shown and prove the accuracy of this new finite element for solving problems of inflatable beams at high pressure

Deflections of highly inflated fabric tubes

“…Analytical solutions show that the compliance matrix of a pressurized cantilever beam is not symmetrical, which was not the case for inflatable panels. The usual equilibrium finite element theory used in [6] cannot simply be applied to these kinds of problems. We have therefore chosen to use algebraic operations to derive a new finite element for the tubes which has, moreover, the property of giving an exact solution, and allows the study of tubes in hyperstatic configurations.…”

“…The theory of inflatable fabric panels defined in [1] was the first attempt to built a finite element devoted to predicting inflatable panels deflections for hyperstatic configurations [6]. The compliance matrix of an inflatable panel in an isostatic configuration is symmetric and the usual theory of equilibrium finite elements has been used to construct the free displacement finite element able to solve the behaviour of inflated panels for hyperstatic configurations.…”

“…For inflatable panels, the compliance matrix of a cantilever-inflated panel is nothing but the sum of the yarn and beam compliances. The stiffness matrix depends on the inflation pressure and is simply obtained by the usual theory of the equilibrium FEM [6]. For tube problems, the compliance is not symmetrical.…”

Structural behavior of asymmetric spindle-shaped Tensairity girders under bending loads

“…Finite elements for predicting the static response of inflated membrane structures were developed [7,8] as well as a Timoshenko beam finite element to predict the deflection and wrinkling load of airbeams at high internal air pressure [9].…”

Effect of Fabric Webs on the Static Response of Spindle-Shaped Tensairity Columns

“…Various authors developed finite elements for predicting the static response of inflated membrane structures (Oden and Sato 1967;Kyriakou et al 1996). Wielgosz and Thomas (2003) developed a Timoshenko beam finite element and predicted deflections along the span and wrinkling loads of inflatable fabric beams at high internal air pressure subjected to 3-point bending. Reese et al (2001) applied a hyperelastic material model for the fabric and developed a brick finite element for the coating and non-linear truss elements for the fibers to predict the static response of a membrane under pressure.…”