Multistable shells with designable configurations based on localized nanocrystallization processes

Abstract

Highly multistable shells of designable configurations are proposed for morphing surfaces, which are manufactured by using nanocrystallization process, i.e. surface mechanical attrition treatment (SMAT). Through a localized treatment, the nanostructuring process can bring bistable properties for localized regions, whose configurations were determined by their shapes and sizes. With coupled deformations among multiple nanostructured regions, the processed shell can hold different stable configurations with localized bistable regions capping toward different sides. The stable configurations are determined by the shapes and sizes of the localized bistable regions and their in-plane distributions. Furthermore, the stable configurations of the multistable shells can be further mechanically modified by plastic bending. To guide the design and investigation of the multistable behavior, finite element analysis and experimental work have been conducted to correlate the stable configurations to design parameters, including shapes and sizes of the localized nanostructuring regions, their pattern distributions, applied mechanical processes as well as boundary conditions.

Keywords

• SPD
• Nano grain
• Residual stress
• Multistable shell
• Finite element analysis