自愈合纤维束材料的愈合过程及对力学性能影响研究

Self-healing (SH) is one of the fascinating properties for bio-materials such as skin and bone. Artificial materials with the SH property can monitor their structural integrity and mend themselves, and hence study on SH materials and their properties is of great importance in scientific researches and engineering applications. Reports showed that animal bone is a load-bearing structure composed of fiber bundles of mineralized collagen while the support structure composed of cellulosic fiber exists widely in plants. Aiming at fiber bundle materials, this project is to study the relevant mechanics problems during the SH process. Through the analysis to components, properties and structures, the fundamental mechanical properties including stiffness, toughness and strength will be investigated. Taking the healing rate as the basic healing parameter, the improved fiber bundle model will be developed to study the SH process and the mechanical properties. Influences of the host material, the healing agent and the structure feature are then examined. An analysis approach will be established in which the healing parameter and the structural feature are taken into account, and then applied to studying the healing process and its effect on fiber bundle materials under practical mechanical environments. The ideal artificial SH fiber bundle materials with prominent healing and mechanical properties will be eventually designed. This project can furnish the fundamental theories, the modeling technique and the analysis approach for shedding new light on the SH mechanism of natural materials as well as for designing artificial SH materials.

自愈合是皮肤、骨骼等生物材料的独有特性，自愈合人工材料会自适应地具有监控结构完整性和修复自身缺陷等优异性能，开展自愈合材料及其性能研究，具有重要的科学意义。研究发现，动物骨骼是由胶原蛋白纤维束经矿化而成的一种承载结构，植物中也存在大量由纤维素纤维构成的保护结构。本项目以纤维束材料为对象，开展自愈合材料愈合过程中的相关力学问题研究。通过组成成分、性能及结构分析，研究纤维束材料的刚度、韧性和强度等基本力学性能；以愈合度为基本愈合参数，提出改进的纤维束模型，研究纤维束生物材料的愈合过程、力学性能，分析本体材料、愈合剂材料性能及纤维束材料结构等因素的影响；发展计及愈合参数和结构特征的分析方法，研究纤维束材料在实际力学环境下的愈合过程及对宏观力学性能的影响；设计具有优异愈合特性和力学性能的理想人工自愈合纤维束材料。为揭示生物材料的自愈合机制、设计人工自愈合材料提供基础理论、建模技术和分析手段。

本项目以纤维束材料为对象，开展了其力学行为及力学环境适应性研究。基于Weibull分布和Daniels纤维束理论，建立了纤维束材料的非线性本构关系，反映了分级和自愈合两种纤维束材料的主要特征；采用两个相反的Heaviside函数将不同区域的本构关系进行无缝对接，建立了纤维束材料的全程本构关系，准确识别了多种纤维束材料的区域临界应变、弹性模量、强度及韧性等重要材料参数；提出了模拟力学环境的弹簧-纤维束材料串联系统，建立了纤维束材料环境适应性分析方法，评价了分级纤维束材料对力学环境的适应能力。研究结果为纤维束材料的工程应用奠定了理论基础。. 本项目系统研究了非均质材料的梁板理论。基于梁板问题的基本假设和基本条件，提出了轴向（面内）高阶位移模式的正交展开表示形式，导出了拉-弯解耦的本构关系，建立了变分自洽的高阶理论和变分渐近的低阶理论，实现了解析求解和有限元求解。本研究阐明了各种梁板理论间的关系，提出了非均质梁板剪切系数的计算公式，揭示了级数解存在较大偏差的理论根源。研究思想也在非均质纳米梁及圆弧形曲梁问题中得到了成功应用。. 通过本项目研究，在J Mater Sci、J Mech Behavior Biomed Mater、Int J Fracture、AIAA J、Euro J Mech /A、ASME J Appl Mech和Comp Struct等本领域国际知名学术期刊和《力学学报》、《中国科学（技术科学）》等本领域国内知名学术期刊发表论文14篇，撰写《梁板理论新解》和《非均质梁板新理论与应用》2部专著。