Abstract: Transforming planar sheets into desired 3D configurations has emerged as a promising design methodology, which provides new means for the fabrication of the biotechnology, actuators, sensors, and engineering of complex metamaterials. Among various approaches to producing planar-to-3D structures, there are still limitations such as high cost, tedious procedures and non-free-standing operation. Considering the polymerization characteristics of photocurable resin in front photopolymerization process, a design method for transforming planar sheets to 3D configurations using mismatch stress is presented. Based on the influence of discrepant photo patterns on the polymerization degree and the distribution of shrinkage stress gradient along the curing thickness, the composite beam theory is proposed theoretically. Thus, the buckling deformation equations of the quasi-one-dimensional beam are derived to obtain the relation between the bending curvature and the exposure dose. On the basis of this, for the bifurcation and rebelliousness in the quasi-two-dimensional plane structure, the elastic potential energy function is established to calculate the energy density of the bending plane, which combines with finite element calculation to reveal the deformation geometry and stress distribution law. The final mechanical experiments as well as the shape transformation examples of petal, claw, icosahedron, and pyramid verify the feasibility of our approach.

Key words: buckling deformation, front photopolymerization, self-folding, shape-shifting