Incorporating Higher Order Tensors in the Computation of Polymer Composite Mechanical Properties

这项研究的目的是开发一种从高阶取向张量来评估短纤维和长纤维增强聚合物复合材料的力学性能的预测能力。该方法是开发一种自动化的三维有限元程序，根据纤维悬浮液的取向分布和组成材料的力学性能来预测纤维悬浮液的有效力学性能。这项工作还包括使用Micro-CT成像技术测量纤维取向，以及开发一种从聚合物熔体流动模拟结果数值生成纤维样品的计算方法。作为这项研究的一部分，将使用蒙特卡罗模拟程序来评估预测性能的统计性质，并将在与工业相关的产品上演示模拟方法。纤维增强聚合物复合材料是许多工程应用中的首选材料，部分原因是它们具有优异的强度与重量比。对于长纤维和短纤维复合材料产品尤其如此，这些产品也受益于极其多样化的制造方法，如注塑成型。因此，在商业产品中加入更多纤维增强聚合物的努力仍在继续，特别是在美国汽车行业，未来的汽车必须减少重量、排放和燃油消耗。事实上，美国能源部2010年的FreedomCAR计划的一个具体目标是将汽车结构的重量减轻50%，而成本和耐用性与目前的产品相同。该研究项目将重点放在纤维增强聚合物产品及其制造工艺之间的关键环节上，从而支持了他们积极进取的目标。这项研究还包括开发教育可视化工具，为未来的工程专业学生提供对纤维悬浮力学更清晰的理解。

The objective of this research is to develop a predictive capability that evaluates the mechanical properties of short and long fiber reinforced polymer composites from higher-order orientation tensors. The approach is to develop an automated three-dimensional finite element procedure for predicting the effective mechanical properties of a fiber suspension from its orientation distribution and the mechanical properties of the constituent materials. The work also includes measuring fiber orientations with micro-CT imaging techniques and developing a computational approach for generating fiber samples numerically from polymer melt flow simulation results. As part of this research, a Monte Carlo simulation procedure will be used to assess the statistical nature of the predicted properties, and the simulation methodology will be demonstrated on industrially-relevant products.Fiber reinforced polymer composites are the material of choice in numerous engineering applications, due in part to their superior strength to weight ratio. This is especially true for long and short fiber composite products, which also benefit from extremely versatile manufacturing methods such as injection molding. As a result, there continues to be a major effort to incorporate more fiber reinforced polymers in commercial products, particularly in the US automotive industry where future vehicles must have reduced weight, emissions, and fuel consumption. Indeed, a specific objective of the 2010 FreedomCAR program at the US Department of Energy, a co-sponsor and collaborator of this research, is to reduce the weight of an automotive structure by 50 percent for the same cost and durability as seen in today's products. Their aggressive goal is supported under this research project by its focus on a critical link between a fiber reinforced polymer product and its manufacturing process. The research also includes the development of educational visualization tools that will provide a clearer understanding of fiber suspension mechanics for future engineering students.