John A. Paulson School of Engineering and Applied Sciences and Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02138.
Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19104.
Proc Natl Acad Sci U S A. 2018 Feb 6;115(6):1198-1203. doi: 10.1073/pnas.1715157115. Epub 2018 Jan 18.
Natural composites exhibit exceptional mechanical performance that often arises from complex fiber arrangements within continuous matrices. Inspired by these natural systems, we developed a rotational 3D printing method that enables spatially controlled orientation of short fibers in polymer matrices solely by varying the nozzle rotation speed relative to the printing speed. Using this method, we fabricated carbon fiber-epoxy composites composed of volume elements (voxels) with programmably defined fiber arrangements, including adjacent regions with orthogonally and helically oriented fibers that lead to nonuniform strain and failure as well as those with purely helical fiber orientations akin to natural composites that exhibit enhanced damage tolerance. Our approach broadens the design, microstructural complexity, and performance space for fiber-reinforced composites through site-specific optimization of their fiber orientation, strain, failure, and damage tolerance.
天然复合材料表现出非凡的机械性能，这通常源于连续基体中的复杂纤维排列。受这些自然系统的启发，我们开发了一种旋转 3D 打印方法，该方法仅通过改变相对于打印速度的喷嘴旋转速度，就能够在聚合物基体中对短纤维进行空间控制的取向。使用这种方法，我们制造了碳纤维-环氧树脂复合材料，这些复合材料由具有可编程定义纤维排列的体积元（体素）组成，包括具有正交和螺旋纤维取向的相邻区域，这导致非均匀应变和失效，以及那些具有类似于天然复合材料的纯螺旋纤维取向的区域，其表现出增强的损伤容限。我们的方法通过对纤维取向、应变、失效和损伤容限进行特定位置的优化，拓宽了纤维增强复合材料的设计、微观结构复杂性和性能空间。
