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Analytical model for the air permeability of parachute fabric and structure parameters sensitivity analysis

Abstract To explore the effect of structure parameters on the air permeability of parachute fabric, the parachute fabric was treated as a porous medium. A nonlinear model of the viscosity and the inertia coefficient of the parachute fabric was established based on the Ergun formula, and an an alytical model of the fabric permeability with the fabric structure parameters was established considering the air permeability of fabric with the standard differential pressure. The results, which were compared with the two-point reverse estimation method showed that the new model is more accurate and has a wider applicable dynamic pressure range. Based on this, a sensitivity analysis of the effect of the fabric structure parameters on the air permeability of parachute fabric was conducted. The results showed that (1) the air permeability of fabric decreases with the increasing fabric planar weight and increases with the increasing fiber density and fabric thickness, and (2) the fabric planar weight has a greater influence on the air permeability of the fabric when the fabric structure parameter is less than the standard structure parameter. The thickness of the fabric has a significant effect on the air permeability of fabrics when the fabric structure parameter is greater than the standard structure parameter.