Shape Morphing of Tubular Structures with Tailorable Mechanical Properties

Abstract

Tubular structures are in high demand in robotics, medicine, and electronics. They are expected to match different shapes under loading and simultaneously exhibit certain mechanical behavior, e.g., specific radial strength and local flexibility, that poses a complex engineering design task. Herein, strategies to achieve programmable shape morphing in patterned tubular structures are explored, whose mechanical properties for all types of deformation modes can be tailored on demand. The general design problem is formulated, and the programmable response for fundamental—expansion, bending, and twisting—modes activated by tension and pressurization is demonstrated. The design problem for expansion modes is solved analytically; the numerical results agree well with the experimental data for stereolithography three‐dimensional printed cellular tubes. The effects of loading and boundary conditions on the deformed shapes and the structural mechanical response are analyzed. Algorithm‐based design strategies are proposed to achieve quantitative and automatic design for complex deformation modes. The possible use of the proposed structures is also discussed with respect to several applications. The findings pave the way for multifunctional tubular structures by exploring the pluridimensional space of the geometric parameters of metamaterial patterns.