【作者】 黄赞；

【导师】 瞿金平；

【作者基本信息】 华南理工大学 ， 机械设计及理论， 2014， 博士

【摘要】 短纤维增强热塑性塑料广泛应用于制造业，由于其物理性能比填充的基体有显著的提高。填充体系的流变行为一般相当复杂，因为纤维取向和流动之间是强耦合作用，并且纤维的取向分布决定了其改善的程度。理解纤维如何伴随着流动演化能极大帮助预测复合材料的微观结构和最终性能。本文利用双极坐标系对基于拉伸力场的挤出设备——叶片挤出机的叶片塑化输运单元进行建模与分析，根据其物理模型建立合理的数学模型，并且结合合理的假设，通过数学方法求解植物纤维悬浮流在叶片挤出机输送阶段的叶片塑化输运单元中速度场。并讨论植物纤维的含量和长径比以及叶片单元的偏心距对速度场的影响，为植物纤维悬浮流提供相应的宏观流场信息。推导出植物纤维悬浮流在剪切-单轴拉伸流场下的取向概率分布函数，并且充分利用数学软件Matlab进行编程，使得相应的解析解可视化，并推导其取向张量方程。分别求解植物纤维的含量、长径比、叶片单元的偏心距对植物纤维悬浮流中植物纤维的取向概率分布函数的影响。通过剑麻/聚丙烯复合材料在基于拉伸力场的挤出设备——叶片挤出机中加工，分别做冷却拆机和挤出制备实验，验证植物纤维悬浮流的理论分析和数值求解的结果。本文通过解析、数值、实验三种手段求解基于拉伸力场的植物纤维复合材料的取向分布和流变特性。三种方法互相联系、互相影响、互相印证。实现纤维悬浮流的解析、数值、实验的有机结合。更多还原

【Abstract】 Short fiber reinforced thermoplastics are widely used in manufacturing industry, becauseof its physical properties is more increasing than filling matrix. The rheological behavior offilling system is quite complicated generally, because it is a strong coupling between the fiberorientation and flow together, the orientation distribution of fibers determines the degree ofimprovement. Understanding the evolution of how fiber along with flow to help predict themicrostructure and the final performance of composites.In this paper, bipolar coordinate system is used to modeling and analysis for vaneplasticizing and conveying units (VPCU) of vane extruder based on extensional force field.Establishing reasonable mathematical model according to its physical model, and combiningwith reasonable assumptions, the velocity field of plant fiber suspension flow at conveyingstage for VPCU of vane extruder is obtained by mathematical method. And the influenced ofvelocity field by the concentration and length to diameter ratio of plant fiber, eccentricity ofVPCU are discussed, it can provide the corresponding macroscopic flow field information forplant fiber suspension flow.The probability distribution function of plant fiber orientation in plant fiber suspensionflow based on shear-uniaxial extensional flow is deduced, the mathematical software Matlabis used fully to program, and make the corresponding analytical solution visualization, itsorientation tensor equation is derived. The influenced of plant fiber orientation probabilitydistribution function by the concentration and length to diameter ratio of plant fiber, theeccentricity of VPCU in plant fiber suspension flow are discussed.Cooling teardown and extruding preparation experiment respectively are made in vaneextruder based on extensional force by SF/PP, the theory analysis and numerical results ofplant fiber suspension flow are proved.In this paper, solve the orientation distribution and rheological properties of plant fibercomposites based on extensional force field by analytical, numerical and experimentalmethods. Three ways to contact each other, influence each other, support each other. Realizethe combination of fiber suspension flow by analysis, numerical and experimental.更多还原