Measuring and modeling the dynamics of stiffened thin-film polyimide panels

Stiff, ultralightweight thermal-formed polyimide panels are examples of next-generation space structures that address some of the issues of membrane-dominated ultralightweight structures while maintaining their low mass and low stowage volume characteristics. The research presented here involved dynamically characterizing and modeling two of these panels, one 0.0625 m(2) with a mass of 38 g and the other 0.1875 m(2) with a mass of 81 g, to develop validated computer models that can be used to determine the effects of changing manufacturing parameters and scalability. Modal testing using an impact hammer and accelerometer extracted the first four structural natural frequencies, the first occurring at 71.9 Hz. These data were replicated by simple, coarsely meshed shell element finite element models that are significantly smaller than previous finite element models of similar structures.