Programmable morphing composites with embedded continuous fibers by 4D printing

Controllable morphing is still a challenge in the field of 4D printing. In this paper, a novel 4D printing technology of composites with embedded continuous fibers is introduced, and the bilayer prepared by this technology can realize programmable deformation with a high deformation accuracy. The deformation of the composite structure is caused by the difference of coefficients of thermal expansion (CTEs) between continuous fibers and flexible matrix. The angle between the intersecting fibers determines the size of the principal curvature, while the bisector of the angle of the fibers determines the direction of the principal curvature. Utilizing this rule, deformation of arbitrary deployable surface can be realized by designing the fiber trajectories. The high control accuracy of fiber orientation leads to a high deformation accuracy of 4D printed structure. The error between the theoretical value and the experimental value of the conical surface curvature is not more than 6%. In addition, the smart composite structure with the ability of temperature response and self-actuated deforming composite structure have also been prepared by this 4D printing process. (C) 2018 Elsevier Ltd. All rights reserved.