纺织织物增强形状记忆聚合物复合材料热—力学行为研究

发布时间：2019-06-06 09:16

【摘要】：形状记忆聚合物能在外界激励下由临时形态回到初始形态,是一种具有形状记忆效应的新型功能材料。形状记忆聚合物的缺点主要在于强度低、刚度小、回复力弱等,严重影响其实际应用。利用纺织织物增强的方法,可以明显改进这些不足,并有效均匀复合材料面内性能和改善面外性能。目前对于纺织织物增强形状记忆聚合物复合材料(纺织SMPCs)热-力学行为研究工作较少,本文主要针对此课题做了如下工作:首先,建立了纺织SMPCs的多尺度力学模型。根据三维机织复合材料细观结构提出了一种新的建模方法,以纱线密度及纱线填充因子为主要参数建立了三维机织SMPCs参数化细观结构模型。其次,对平面机织SMPCs的形状记忆性能进行了研究,分析了织物增强层拉伸模量、弯曲模量对其热力循环的影响。将平面机织SMPCs在厚度方向划分为5层,研究了铺层位置对其热-力学行为的影响。结果表明,纯弯曲状态下平面机织SMPCs形状记忆性能只与弯曲模量有关,织物处于拉伸侧有利于提高形状固定率及回复力。再次,基于多尺度模型,通过基体的粘弹性参数和纤维的弹性常数,导出纱线的三维热粘弹性本构关系,给出了正交各向异性粘弹性材料ABAQUS子程序的编写方法。研究了外载荷及细观结构对三维机织SMPCs细观单胞等效热粘弹性能的影响。最后,以热粘弹性能的研究为基础,对三维机织SMPCs的形状记忆行为进行了分析,模拟了自由回复与约束回复两种热力循环,研究了外载荷及机织参数对其记忆性能的影响。
[Abstract]:Shape memory polymer can return from temporary morphology to initial form under external excitation. It is a new functional material with shape memory effect. The main disadvantages of shape memory polymer are low strength, low stiffness, weak recovery force and so on, which seriously affect its practical application. By using the method of textile fabric reinforcement, these shortcomings can be obviously improved, and the in-plane properties and out-of-plane properties of composite materials can be effectively uniform. At present, there is little research on thermal-mechanical behavior of textile fabric reinforced shape memory polymer composites (textile SMPCs). The main work of this paper is as follows: firstly, the multi-scale mechanical model of textile SMPCs is established. According to the meso-structure of three-dimensional woven composites, a new modeling method is proposed. The three-dimensional woven SMPCs parametric meso-structure model is established with yarn density and yarn filling factor as the main parameters. Secondly, the shape memory properties of planar woven SMPCs were studied, and the effects of tensile modulus and bending modulus of fabric reinforced layer on its thermal cycle were analyzed. The plane woven SMPCs is divided into five layers in the thickness direction, and the effect of paving position on its thermal-mechanical behavior is studied. The results show that the shape memory performance of plane woven SMPCs is only related to the bending modulus in pure bending state, and the shape fixation rate and recovery force of the fabric are improved by being on the tensile side. Thirdly, based on the multi-scale model, through the Viscoelastic parameters of the matrix and the elastic constant of the fiber, the three-dimensional thermal Viscoelastic Constitutive relation of the yarn is derived, and the method of compiling the subprogram of the orthotropic Viscoelastic material Abaqus is given. The effects of external load and meso-structure on the equivalent thermal Viscoelastic properties of three-dimensional woven SMPCs meso-unit cells were studied. Finally, based on the study of thermal Viscoelastic properties, the shape memory behavior of 3D woven SMPCs is analyzed, two kinds of thermal cycles, free recovery and constrained recovery, are simulated, and the effects of external load and weaving parameters on their memory performance are studied.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB332

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