Stress Analysis of Parachutes Using Finite Elements

An analytical method has been developed for determining the unique shape and internal load distribution that satisfies equilibrium and boundary conditions for a parachute under the influence of known riser and aerodynamic forces. The parachute is treated as a deformable membrane, using finite elements with nonlinear elastic properties to represent the structure. An iterative procedure, performed by a digital computer, is used to find the equilibrium shape. The method is applicable to polysymmetric parachutes which have meridional members (cords or radial tapes) that can be assumed to carry all meridional forces in the canopy. Reefed and nonreefed configurations can be analyzed, and the canopy may be fully or partially inflated. Predicted canopy shapes and failure loads are shown to agree with aerial drop test results.