仿贝壳珍珠母多级结构的力学性能及强韧化机制研究

Nacreous layer has played an important role in the research of bionic design because of its light weight, high strength, and structural and functional integration. The accurate description and quantitative characterization of bionic nacreous layer behavior is the key to explaining its strengthening and toughening mechanism. However, the multi-level strengthening and toughening of nacreous layer and its bionic manufacture remain less explored. To this end, by combining the 3D printing technique and multiscale method, this project aims to in-depth explore the mechanical properties of the bionic laminated structure and reveal the structure-strength relationship and strengthening and toughening mechanism. This project will use 3D printing technology to progressively fabricate bionic laminated structures and measure their mechanical performance. In parallel, this project will develop a bottom-up multiscale theoretical model. Starting with the detailed physical structure of the 3D printing sample, we will investigate the interaction between the soft and hard phases as well as the mechanical properties of the bionic laminated structures, which effectively bridge the gap between the microscale parameters and macroscopic mechanical properties and proposes a general theoretical framework related to the bionic composite material. Through the 3D printing technique and the theoretical approach, this project will deepen the understanding of the strengthening and toughening mechanism of bionic nacreous layer, which will contribute to the design and manufacture of bionic composite materials and possess the significant potential to develop high-performance bionic composite materials.

贝壳珍珠母由于其轻质高强、结构功能一体化等特点在仿生设计研究中扮演着重要角色。真实的描述和分析仿珍珠母多级结构和性能是解释其强韧化机制的关键所在。然而仿珍珠母多级结构才刚刚起步，有待于深入研究。为此，本项目提出利用3D仿生打印制备实验和跨尺度理论相结合的方法，深入探索仿珍珠母多级层叠结构力学性能，揭示仿珍珠母结构-强韧性能耦合机理。本项目将采用3D打印技术，逐级逐层制备仿珍珠母多级层叠试样，测定其力学性能。同时，本项目将开发自下而上的跨尺度理论计算模型，从3D打印试样详细物理结构出发，深入研究仿珍珠母软硬相间相互作用，到仿珍珠母的层叠结构的宏观力学性能，有效将微观参数与宏观力学性能联系起来，并提出用于研究仿生复合材料强韧性的普适性理论方法。通过3D打印制备方案和理论手段，本项目将加深对仿贝壳珍珠母结构强韧机制的理解，有助于仿生复合材料的设计与制造，对开发高性能仿生复合材料具有重大意义。

珍珠层由于其轻质高强、结构功能一体化等特点在仿生设计研究中扮演着重要角色，真实的描述仿珍珠层多级结构和性能是解释其强韧化机制的关键。本项目从珍珠层微观机理、仿珍珠层结构力学性能、宏-微跨尺度理论、3D打印仿珍珠层结构力学性能、以及3D打印复合材料太赫兹检测与评估方面开展研究。首先在全原子体系中研究了珍珠层的微观力学性能，揭示了珍珠层的组分增韧机理。其次以石墨烯和聚合物为基建立了仿珍珠层石墨烯/聚合物复合结构，采用粗粒化分子动力学方法分析了仿珍珠层结构介观尺度拉伸和冲击力学性能。进一步研究了跨尺度力学性能分析方法，将微观下离散的、高精度的原子区域与宏观下有限元区域耦合，实现较高精度、较快速度、较大结构尺寸的跨尺度并行仿真，验证了多尺度耦合方法对分析多尺度结构力学性能的有效性。同时，研究了仿珍珠层结构的3D打印制备方法，分析了仿珍珠层复合结构的压缩力学性能。最后，针对3D打印多层复合结构界面损伤失效问题，提出了基于时域太赫兹光谱技术的3D打印复合材料界面缺陷检测与评估方法，有效地稀疏重构3D打印复合材料内部的缺陷特征。本项目通过基础理论分析和3D打印制备，揭示仿珍珠层的组织结构及赋予其优异性能的关键机理，提炼天然与人造材料共性的优化设计原则，构筑相似甚至超越自然生物体功能的新型仿生材料，将有助于高效仿生复合材料的设计与制造。