Inverse design and additive manufacturing of shape-morphing structures based on functionally graded composites

TL;DR

This paper introduces an inverse design method for shape-morphing structures using functionally graded composites, enabling precise control of shape transformation and multifunctionality through tailored modulus distribution.

Contribution

The study presents a novel inverse design framework that modifies bending stiffness via graded composites, allowing for customizable shape-morphing structures with validated numerical and experimental results.

Findings

Successful numerical and experimental realization of diverse Gaussian curvature structures.

Good agreement between measured shapes and target morphologies.

Enhanced multifunctionality demonstrated through compression and energy absorption tests.

Abstract

Shape-morphing structures possess the ability to change their shapes from one state to another, and therefore, offer great potential for a broad range of applications. A typical paradigm of morphing is transforming from an initial two-dimensional (2D) flat configuration into a three-dimensional (3D) target structure. One popular fabrication method for these structures involves programming cuts in specific locations of a thin sheet material (i.e.~kirigami), forming a desired 3D shape upon application of external mechanical load. In this paper, a novel inverse design strategy is proposed by modifying the bending stiffness via introducing distributed modulus in functionally graded composites (FGCs). The longitudinal modulus of each cross-sectional slice can be controlled through the rule of mixtures, hence matching the required modulus distribution along the elastic strip. Following the proposed framework, a diverse range of structures is obtained with different Gaussian curvatures in both numerical simulations and experiments. A very good agreement is achieved between the measured shapes of morphed structures and the targets. In addition, the compressive rigidity and specific energy absorption during compression of FGC-based hemi-ellipsoidal morphing structures with various aspect ratios were also examined numerically and validated against experiments. By conducting systematical numerical simulations, we also demonstrate the multifunctionality of the modulus-graded shape-morphing composites. This new inverse design framework provides an opportunity to create shape-morphing structures by utilising modulus-graded composite materials, which can be employed in a variety of applications involving multi-physical environments. Furthermore, this framework underscores the versatility of the approach, enabling precise control over material properties at a local level.