多尺度增强FMLs的力学性能及其增强机理研究

With their high specific modulus and strength, fiber metal laminates (FMLs) profiting from the advantages of the both materials of fiber reinforced plastics (FRP) and metals have shown great potentials for extensive structural applications including aerospace, automobile and military industries where high performance and lightweight of structures are essential. However, their relative weak out-plane interlaminar mechanical properties limit their further applications. This project aims at developing a new multi-scale reinforced method, revealing the reinforced mechanism and optimizing the reinforced effects for FMLs through experimental and theoretical investigation. To this end, in the experimental aspect, three toughening strategies will be employed in the multi-scale reinforced method. (1) The matrix of FRP layer will be synergistically reinforced by using hybrid nanostructured fillers i.e. surface modified carbon nanotube/graphene oxide (SCNT-GO); (2) SCNT/GO hybrid nanofiller will be introduced into the interface of FRP and metal layer; (3) The morphology of metal sheet surface will be modified to patterned hierarchical structure based on bio-inspired methods to enhance the interface bonding between the metal and FRP layer of FMLs. Therefore, the mechanical properties especially interlaminar mechanical properties of FMLs will be dramatically improved. In the theoretical aspect, in order to thoroughly uncover the reinforced mechanism, a novel multi-scale modeling technique will be developed based on molecular dynamics (MD) simulation, micromechanics and finite element modeling to evaluate and optimally design the mechanical properties of multi-scale reinforced FMLs nanocomposites. The simulation results will be verified experimentally and provide valuable optimal design guidelines of experiments under nano-, micro- and macro-scales. The outcomes of this project will provide technical and theoretical supports for the development and application of new FMLs with high performance.

由于具有很高的比强度和比刚度，并同时兼具纤维增强塑料（FRP）及金属材料的优点，纤维金属层板（FMLs）在航空航天、汽车、军工等高科技领域具有广泛的应用前景。然而其相对较弱的层间力学性能限制了其进一步的应用。本项目旨在开发新的FMLs多尺度增强方法，揭示其增强机理，优化其增强效果。为此：在实验方面通过在FRP层的基体及FRP与金属层间添加表面改性碳纳米管/氧化石墨烯（SCNT/GO）混合纳米相进行协同增强；在金属表面进行基于仿生原理的多尺度阶层纹理结构加工对FMLs 的综合力学性能尤其是层间力学性能进行改进。为了揭示其增强机理，在理论上通过结合分子动力学（MD）、细观力学、有限元模拟发展一种全新的多尺度模拟方法对多尺度增强FMLs的力学性能进行分析评价并与实验结果进行对比验证。以此在纳观、细微观、宏观等不同尺度进一步指导优化实验。该研究将为新型高性能FMLs的开发及应用提供技术和理论基础。

由于具有很高的比强度和比刚度，并同时兼具纤维增强塑料（FRP）及金属材料的优点，纤维金属层板（FMLs）在航空航天、汽车、军工等高科技领域具有广泛的应用前景。然而其相对较弱的层间力学性能限制了其进一步的应用。本项目旨在开发新的FMLs多尺度增强方法，揭示其增强机理，优化其增强效果。为此：在实验方面通过在FRP层的基体及FRP与金属层间添加碳纳米材料进行协同增强；在金属表面进行基于仿生原理的多尺度阶层纹理结构加工对FMLs 的综合力学性能尤其是层间力学性能进行改进。为了揭示其增强机理，在理论上通过结合分子动力学（MD）、细观力学、有限元模拟对多尺度增强FMLs的力学性能进行分析评价并与实验结果进行对比验证。以此在纳观、细微观、宏观等不同尺度进一步指导优化实验。通过三年的研究，取得的重要代表性结果包括在试验研究方面，通过结合金属表面处理技术及在层间添加表面改性的纳米碳纤维对纤维金属层板GFRP/Al 的层间力学性能进行改进研究，取得了良好的增强效果使得其临界载荷及II型断裂韧性分别提高了135.51% 和425.16%，层间剪切强度提高了153.33%，并对其增强增韧机理进行详细分析。在理论计算方面，通过分子动力学模拟研究了杂化石墨烯和碳纳米管（hybrid graphene-carbon nanotube）与高分子基体的界面力学性能，得到了一系列重要的研究结论如： hybrid GR-CNT相比GR具有更好的与高分子基体的界面力学性能。并对其增强机理进行相应的分析和揭示。在本项目的支持下共发表高水平SCI论文10余篇，申请专利3项。该项目的研究成果将为新型高性能FMLs的开发及应用提供技术和理论基础。