Shape morphing structures inspired by multi-material topology optimized bi-functional metamaterials

Abstract

Shape morphing structures consisted of the metamaterials would present desired morphing reaction in response to the external stimuluses and thus attract numerous attentions. However, reported designs can only serve well under the mechanical loadings due to the single tunable property. Here, through assembling the bi-functional metamaterials with different geminations of the Poisson’s ratio (PR) and coefficient of thermal expansion (CTE), the applicability of the designs is effectively enlarged. Based on the multi-material topology optimization, a series of re-entrant and chiral metamaterials with full gemination of the bi-function were developed, e.g., the negative PR & CTE, negative PR & positive CTE and even zero PR & CTE. The influences of the base materials’ proportion on the topology-optimized results were also identified, bringing out general guidelines to the selection of appropriate parameters. Driving by the objective deformation modes, the parameterized metamaterials were finely optimized to construct the shape morphing structures. Numerical simulations show that the resultant designs could exactly present the desired morphing behavior under not only the mechanical loading but rather the thermal and thermomechanical loadings. These approaches proposed here open new avenues to bring the shape morphing structures much more extensive applications in the aerospace, electric and biomedical domains.