MECHANICS OF AIR-INFLATED DROP-STITCH FABRIC PANELS SUBJECT TO BENDING LOADS

摘要

Rapid deployment and mobility of lightweight structures, namely inflatable structures, are of growing significance to the military and space communities. When deployment and rigidity are driven by pressure (for example, air or fluid) and materials such as textiles, elastomers and flexible composites are used, significant load carrying capacity per unit weight (or per-unit stowed volume) can be uniquely achieved. Specifically, the pressurized air directly provides the stiffness to support structural loads, thus eliminating the requirement for heavy metal stiffeners that are used in conventional rigid structures. However, the material and system behaviors are not sufficiently understood. Furthermore, predictive-performance analysis methods and test standards are not adequately established because the behaviors of inflatable fabric structures often involve coupled effects from inflation pressure such as fluid-structure interactions (FSI's), thermo-mechanical coupling and nonlinear constitutive responses of the materials. These effects can restrict the use of conventional design, analysis and test methods. This research explores the mechanics of air-inflated drop-stitch fabric panels subject to bending loads using analytical and experimental methods. Results of experimental four-point bend tests conducted at various inflation pressures are used to validate the analytical method. The predicted and experimental deflections, wrinkling onset moments, ultimate loads, pressure changes, etc. are compared and discussed.