微珠泡沫夹芯复合材料抗撞防护结构冲击动力学与损伤自修复研究

Hollow macro-sphere filled polymer matrix has been used in aerospace, deep-sea submarine and dam structures because of its low density and high compressive strength. High strength and high stiffness fiber reinforced composite materials sandwiched with hollow macro-sphere/polymer matrix core (macro-core) are proposed herein for the development of new anti-collision and protective structures through optimal material selection, innovative structure design and cost-effective molding process. The resulting novel structures are expected to be lightweight, highly energy- dissipative, corrosion resistant, durable, and self-healing enabled for potential applications in road ways, bridges, harbors, waterways, and ocean fronts..The proposed activity will focus on key scientific problems related to material development and engineering application of the proposed structural system. The innovative designs and impact dynamics of composite anti-collision structures coupled with the macro-core will be studied at different loading levels to establish energy absorption mechanisms, damage evolution trends, failure modes and remaining loading capacity. Moreover, hollow macro-sphere and organic polymer capsules will be explored as healing resin carrier. Self-healing mechanism triggered upon macro-sphere break and matrix cracking will be studied and the recovery efficiency of mechanical properties of the macro-core material and composite structure will be determined. Finally, an optimal algorithm to juxtapose different advanced materials will be established to obtain the highest energy absorption efficiency of the macro-core sandwich composite structures. Upon completion of the proposed research, we will provide scientific understanding and theoretical basis for the development and engineering application of a novel anti-collision composite structural system with macro-core providing self-healing properties.

微珠复合泡沫是以中空玻璃微球填充聚合物基体而制成的高承压低密度材料，在国外已用于航空航天、深海潜艇和大坝结构。将抗拉强度优异的纤维复合材料与微珠复合泡沫相结合，通过合理的材料组合、创新的结构设计和先进的成型工艺，形成可充分发挥各组分材料性能、具有轻质、抗撞、耐久、自修复等特点的新型抗撞防护结构，可用于道路、桥梁、港口、水利、海洋等领域。.针对该结构在工程应用中需要重点解决的关键科学问题，本项目首先开展面向不同荷载水平的微珠复合结构创新设计和冲击理论研究；明确该结构在冲击荷载作用下的吸能机理、损伤演化规律和破坏模式；提出撞损后结构剩余承载力表征方法；然后探索以中空微珠和有机高分子胶囊为修复树脂载体，研究针对微珠破裂和基体裂纹的自修复机理，确定芯材和结构的力学性能恢复效率；最终建立基于吸能效果的微珠泡沫夹芯复合材料结构优化方法。本项目的实施为该新型复合材料抗撞防护结构的推广应用奠定理论基础。

将抗拉强度优异的纤维复合材料与微珠复合泡沫相结合，通过合理的材料组合、创新的结构设计和先进的成型工艺，形成可充分发挥各组分材料性能、具有轻质、抗撞、耐久、自修复等特点的新型抗撞防护结构，可用于道路、桥梁、港口、水利 、海洋等领域。.本项目针对该结构在工程应用中需要重点解决的关键科学问题开展研究，得到以下结论：.（1）以获得最佳吸能和抗压承载力为目标，设计制备了不同的GFRP约束微珠泡沫组合柱。通过变化组合柱参数1）FRP壁厚，2）纤维纵/环向体积比，3）泡沫密度和4）十字格构来研究不同的破坏模式。建立带十字格构的FRP-微珠泡沫组合柱轴压承载力和屈曲极限荷载预测方法。.（2）研究微珠泡沫夹芯板在受压荷载作用下的力学性能，并分析了GFRP面层纤维层数，面层纤维纵/横体积比以及微珠泡沫的密度和厚度对夹芯板受压性能、破坏模式和吸能的影响。试验表明增加格构FRP层数能在不增加峰值荷载的情况下提高夹层板吸能能力。此外，还建立了考虑格构影响的夹层板在受压作用下的位移预测模型。.（3）研究GFRP-微珠泡沫夹芯板在低速冲击响应和受冲击后的压缩性能。侧压试验结果表明，无格构的夹芯板破坏模式以面层和芯材界面剥离为主，而有格构腹板的夹芯板破坏模式以面板起皱、剥离和泡沫芯材压碎为主。基于能量法和变分方法，建立了带格构腹板的夹芯板冲击后剩余承载力预测方法。.（4）采用原位聚合法合成聚脲甲醛包覆GE-7118a环氧树脂微胶囊。然后，将微胶囊与树脂基体混合。在固定潜伏性固化剂AD316含量为2.5wt%以及催化温度为100℃条件下，研究了微胶囊的含量对树脂基体自修复效率的影响。拉伸试验表明，随着微胶囊含量的增加，其自修复效率提高。当微胶囊和潜伏固化剂AD316的含量分别为7%和2.5%时，自修复效率为57%。.最终本项目建立了基于吸能效果的微珠泡沫夹芯复合材料结构优化方法，为该新型复合材料抗撞防护结构的推广应用奠定理论基础。