Mechanics of fiber-reinforced hyperelastic solids

Abstract

Recent designs for deployable space structures include elements that can be folded to high curvatures and recover elastically. A type of material proposed for such hinges is fiber composites with a soft silicone matrix. This research focuses on the characterization of this type of composites. Their mechanical properties during folding have been studied experimentally, revealing a highly non-linear moment-curvature relationship and stress softening, due to microdamage. The micromechanics of the problem have also been studied numerically, with a finite element model that takes into account the arrangement of the fibers. The model predicts most of the features observed experimentally, including the microbuckling that reduces fiber strain during folding. The model overestimates the material stiffness, due to its inability to model the damage taking place in the material. Current efforts are focused on modeling this damage process. In order to do so, the tension stiffness transverse to the fibers has been measured. Preliminary results including cohesive elements that delamination show good agreement with the tests.