中文摘要：

三维打印是当今最热门的快速成型方法.随着三维打印技术的发展,人们可以将灵感方便快捷地变成现实.受天然贝壳珍珠层高强度高韧性的启发,利用三维打印技术制备仿生复合材料,结合拉伸实验及有限元方法研究微结构对复合材料断裂模式和断裂韧性的影响.本文探索了利用立体光固化成型三维打印技术制备并研究仿生复合材料的科研模式,在实验室条件下实现了电脑设计到人工合成的快速衔接.

英文摘要：

Additive manufacturing, or 3D printing, is a rapid prototyping method to fabricate 3D objects by depositing various materials layer by layer. Despite its industrial origin and significant commercial impact, 3D printing technique has found its great potential applications in engineering and scientific research. Here, we demonstrate its application in remodeling nacre-inspired bricked structure. Nacres have extraordinary mechanical properties, such as high fracture toughness and high strength-weight ratio, rooted from its brick-and-mortar structure, with Calcium carbonate platelets as hard bricks alternating with proteins layer as soft mortar. Although it is well proposed that the platelets and mortar serve jointly via shear-lag mechanism, experimental studies on the mechanical effects of brick geometry and stiffness ratio between brick and mortar have been limited. With the help of 3D printing technology, we are now able to fabricate nacre-inspired structures with two types of UV- curable polymers, where stiff plastics as brick and soft rubber as mortar. The geometry of brick and mortar can be tuned in much wider range inaccessible to natural nacre. This allow us a thorough exploration in the parameter space, leading to an understanding of the naturally optimized values found in nacre samples. In the study, 5 samples with nacre-inspired brick-and-mortar composited structures are prepared by Object Connex350 （Stratasys, Inc.） 3D printer. The mortar thickness is taken as 0.21 mm limited by the precision of the printer, and the length-to-width ratio of the brick ranges from 3 to 15. These samples are subjected to tensile force until fracture and the whole process are recorded with time lapse camera. We see three distinct regimes of climbing, horizontal, and declining, which can be closely related to elastic deformation, end-rubber fracture, and horizontal-rubber fracture. For different length-to-width ratio, three different fracture modes are observed. When the ratio is small, zigzag tearing path appears across