复合材料热变形的数值模拟.doc

编号 南京航空航天大学 毕业设计 题 目 复合材料热变形的数值模拟 学生姓名 学 号 学 院 航空宇航学院 专 业 飞行器设计与工程 班 级 指导教师 二〇一〇年六月  南京航空航天大学 本科毕业设计（论文）诚信承诺书 本人郑重声明：所呈交的毕业设计（论文）（题目：复合材料热变形的数值模拟）是在导师的指导下本人独立完成的。尽本人所知，除了毕业设计（论文）中特别加以标注引用的内容外，本毕业设计（论文）不包含任何其他个人或集体已经发表或撰写的成果作品。 作者签名： 年 月 日 （学号）：  复合材料热变形的数值模拟 摘 要 本文采用细观有限元模型计算了纤维增强复合材料的热膨胀系数以及细观失配应力，并研究了基体粘弹性对复合材料热膨胀和热失配应力的影响。首先用Msc.PATRAN／NASTRAN软件建立了单向纤维的细观单胞模型，计算出单向纤维复合材料在不同纤维体积分数时的热膨胀系数和热失配应力，并与理论结果进行了比较，在此基础上对理论模型进行了改进。随后在模型中引入粘弹性，研究了基体粘弹性对单向纤维模型热膨胀系数的影响。在此基础上计算了对称正交复合材料的热膨胀系数并模拟了非对称正交模型的降温过程。最后建立了纤维非均匀排布的细观有限元模型，初步研究了纤维排布方式对复合材料热胀性能的影响。 关键词：复合材料，微、细观力学，RVE模型，周期性边界条件，热膨胀系数，粘弹性  Numerical simulation of thermal deformation of composite materials Abstract Meso finite element models were employed for analysis of thermal expansion coefficient and meso-scale mismatch stress of fiber-reinforced composites. The effects of matrix viscoelasticity on thermal expansion and meso-scale thermal mismatch stress in composites were also evaluated in this thesis. Firstly, a meso-scale cell model of unindirectional fiber composite was established and based upon it the thermal expansion coefficient and thermal mismatch stress with various fiber volume fraction were calculated via Msc. Patran/Nastran package. The results were used to improve the theoretical model. Secondly, the viscoelasticity was introduced in resin matrix material and its effect on the overall thermal expansion of unidirectional fiber composites were investigated . thirdly, the thermal expansion coefficient of symmetric orthogonal composite was calculated and the cooling process of non-symmetric orthogonal composite was simulated. Finally, through modeling unit cells with random fiber arrangement, the effects of the fiber arrangement on the thermal properties of composites were studied. Key Words：composite materials; micro and meso mechanics; RVE model; periodical boundary condition; thermal expansion coefficien