Nature uses internal stimuli to locally and globally change the curvature of thin and soft materials in a variety of ways. Natural curvatures occur in many biological and engineered structures through differential swelling, heating, or growth. They are: induced by proteins along a cell membrane, critical to the eversion of a developing Volvox embryo, and incurred in residually stressed composite plates and shells. Since natural curvature can drastically affect the morphology of thin bodies and induce mechanical instabilities, this provides a means for creating adaptive, shape-shifting structures capable of growing, morphing, and transitioning between complex shapes. This award supports fundamental research on the mechanics of instabilities induced by a natural curvature within thin shells. Harnessing these concepts for technological applications may enable the design of adaptive metamaterials, soft robotic actuators, and structural materials capable of programmatically controlled shape-shifting. Thus, this project will advance the science associated with mechanical instability; and advance the national health, prosperity, and welfare. This award also supports the further development of the digital inspiration, communication, and education (DICE) program. By placing an emphasis on visual, verbal, and written communication, this program will continue to enhance both the scientific communication of the next generation of scholars and broaden the participation of the general public through the creation and curation of open, online mechanics content.
This research will establish a fundamental understanding of how natural and spontaneous curvatures deform slender structures and soft materials. Its results will help engineer shells that are more robust against buckling, and facilitate the design of shells capable of changing between target shapes on command. The research will establish how natural curvature can provide shells with a knock-up factor against pressure buckling. The research team will utilize experiments that control curvature in soft materials through residual swelling in conjunction with a novel computational model based on a large deformation, rotation-free shell formulation. A fully nonlinear forward and inverse computational shell model to analyze shells with an evolving natural curvature will be developed and validated with experiments. Finally, an understanding of how locally applied natural curvatures deform soft shells will be established, enabling targeted shape-shifting that utilizes the computational modeling to inform the experimental design. This understanding may transform key technologies where shape-shifting materials are being intensely pursued for technological insertion, like soft robotics, deployable structures, and biomimetic design.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
