Modal testing of an inflated thin film polyimide torus structure

An experimental investigation into the dynamics of an inflated thin film polyimide torus has been performed. This paper describes an effort to define modal test procedures for extremely lightweight, flexible inflated structures. An impact hammer was modified to excite the global modes of the structure, while avoiding local excitation. Coherence measurements are examined to describe the nonlinearity in the structure. Nonlinearities include shell wrinkling and material nonlinearities such as film modulus variations with frequency and temperature. The baseline goal for the modal test is to determine the first six bending modes of the structure.