Membranes, Uniqueness of solutions of equilibrium problems in solid mechanics, Nonlinear elasticity, Uniqueness of solutions of dynamical problems in solid mechanics, Föppl nonlinear membrane theory, annular membrane problem, nonvanishing traction, circular pseudo-membrane problem, Axisymmetric deformations, normal surface loads, existence and uniqueness of tensile solutions, displacements, radial edge loads, reduce to the solution for the circular membrane, stress concentration factor, Stress concentrations, singularities in solid mechanics