Experimental characterization and finite element analysis of inflated fabric beams
Publication Name: Construction and Building Materials
An airbeam is a high-strength fabric sleeve with a highly flexible internal bladder that can be used as a load-bearing beam or arch when inflated. Due to their fabric construction, airbeams are inherently thin-walled structures that are prone to local buckling. In this study, airbeams were tested in bending at different inflation pressures to quantify their loadÐdeformation response and the effect of inflation pressure on response. TensionÐtorsion tests of the airbeam fabric were conducted to estimate the fabric shear modulus, and the bend test results were used in conjunction with Timoshenko beam theory to estimate the fabric elastic modulus. Three-dimensional membrane finite element (FE) models were then used to predict the beam loadÐdeformation response given these moduli. The FE models successfully predicted localized fabric buckling and softening of loadÐdeflection response. Comparison of FE model-predicted loadÐdeflection response with beam theory shows that conventional beam theory is accurate prior to local buckling of the airbeam fabric. The FE model and test results indicate that the consideration of work done by pressure under deformation-induced volume changes may increase beam capacity beyond previously derived theoretical limiting values.