Optimization design and 3D printing of curvilinear fiber reinforced variable stiffness composites

Overall performance of curvilinear fiber reinforced composite structures (CFRCSs) can be designed by adjusting the local fiber orientation and content. In this paper, an optimized design method based on stress gradient distribution for CFRCSs was proposed to improve the efficiency in strength of continuous fiber reinforced composites. The mechanism of fiber content regulation in continuous fiber reinforced composites 3D printing was studied. The adaptive feed calculation method of resin was proposed, and the 3D printing of CFRCSs was realized. A 3D printed composite perforated plate with a hole under tensile loading was optimized and fabricated to verify the effectiveness of the proposed methods. After the optimized design, the maximum stress concentration factor was reduced by 36%, and the ultimate tensile strength was increased by 42%. Through the proposed optimization design method, the fiber content distribution corresponds to the stress distribution, and the fiber direction distribution corresponds to the maximum principal stress direction distribution. At the same time, the stress was redistributed to reduce the stress concentration. Therefore, the ultimate strength was improved. The optimized design method and 3D printing method of CFRCSs have potential application prospects in aerospace, automotive and other fields.