形状记忆合金增强复合材料界面特性及其抗低速冲击性能

Shape memory alloy reinforced composite (SMACs) is one of the focus research in the intelligent material field. Due to the super-elastic and shape memory effect of shape memory alloy, the overall mechanical properties of SMACs can be significantly improved, such as strength, stiffness, toughness, and impact resistance. However, the interfacial cohesive property between shape memory alloy fiber and matrix will affect the enhancement effect of composite. In this topic, the SMACs is regarded as a three-phase system, including the shape memory alloy fibre, matrix, and interphase. The macroscopic constitutive model and effective modulus are obtained through the stress function, shear lag model and energy methods.The interphase failure critia can be derived according to the proposed theoritical model, and then it will be verified through experimental tests. The mechanical properties evolution of super-elastic SMA fiber will be discessed during cyclic loading process. The low-velocity impact process of shape memory alloy mesh reinforced composite is discussed by the high-speed camera system and scanning electron microscopy. The interfacial debonding evolution mechanism of SMACs is investigated through the finite element method based on the proposed interphase critical failure criterion. The investigation in this topic can be used for the technical and theoretical support of aeronautic protective structure.

形状记忆合金增强复合材料目前是智能材料研究领域的热点问题之一，由于形状记忆合金的超弹特性和形状记忆效应，复合材料整体强度、刚度、断裂韧性和抗冲击特性等，均会有所改进。形状记忆合金纤维与基体材料粘结界面，会影响形状记忆合金纤维功能作用的发挥。本课题提出将形状记忆合金增强复合材料整体视为形状记忆合金纤维、基体材料和界面相组成的三相系统，基于应力函数法、剪应力传递模型和能量法，推导其宏观本构模型及有效模量表达形式，并给出界面相临界失效准则，通过实验测试对模型进行验证；讨论循环状态下超弹形状记忆合金力学性能演化形式；结合高速摄像系统和SEM研究形状记忆合金纤维网状结构增强复合材料的低速冲击破坏过程；基于建立的界面相临界失效准则，通过有限元方法揭示形状记忆合金增强复合材料内部界面脱粘演化机制，为其材料在航空航天防护结构的应用提供技术支持和理论指导。

按照计划对“形状记忆合金增强复合材料界面特性及其抗低速冲击性能”进行了研究，分别对形状记忆合金（SMA）增强复合材料的界面特性、抗低速冲击性能以及抗疲劳等性能进行了实验研究、理论建模和数值模拟。在实验研究方面，制备了多种试样进行了不同的力学性能的测试。在理论建模方面，除了对形状记忆合金的本构关系进行了研究之外，还针对复合材料建立了包含增强相、界面和基体的三相理论模型，基于此模型，研究了增强相含量，分布规律，界面尺寸，参数等因素对材料力学性能的影响，进一步模拟了SMA增强复合材料层合板的冲击过程。在有限元模拟方面，对埋入SMA的方形和矩形复合材料层合板偏心冲击进行仿真，研究了埋入SMA丝在矩形和方形复合材料层合板上中心和偏心的低速冲击等问题；建立推导了粘弹性本构模型，扩展了连续介质力学粒子的基本概念，结合分子链的分布规律提出了聚合物的微观模型，并对聚合物基复合材料的多场耦合性能进行了研究；基于粘超弹性理论和统计力学，首次提出了评价表面效应和力电性能的力学模型。为其材料在航空航天防护结构的应用提供技术支持和理论指导。