During the past two centuries, due to too fast growth of the human population, the pollution made by human has seriously impacts on our environment, particularly, for the CO₂ emission. To diminish the CO₂ emission problem, one of the effective solutions is applying lightweight material, such as the fiber-reinforced plastics (FRP), to replace metal in the manufacturing of transportation vehicles. However, since the reinforced function of the fibers inside plastic matrix is very complex, it is not easy to be visualized and managed. Specifically, the connection from microstructures of the fibers to the physical properties of the final product is far from our understanding. In this study, we have proposed a benchmark with three standard specimens based on ASTM D638 with different gate designs. This system is used to study the fiber microstructures and associated mechanical properties using numerical simulation and experimental studies. Results showed that the tensile properties (including tensile modulus and tensile stress) of all three ASTM standard specimens can be improved significantly in the appearance of the fibers. Moreover, the tensile properties variation of the finished parts associated with the microstructures of the short fibers based on the gate design have been also investigated. Specifically, the tensile modulus and the strength of the Model I are greater than that of Model II, while Model III is much less than others because of its double gate effect. The reason why the tensile modulus and the strength of the Model I is greater than that of Model II is due to some entrance effect. That entrance effect will further provide flow-induced fiber orientation to melt and then enhance the tensile properties of Model I. To confirm the observation, a series simulation and experimental studies have been performed. Specifically, the fiber orientation distribution is predicted using CAE, and verified using micro-CT scan and image analysis by Avizo software. Hence, the correlation from fiber microstructure feature (particularly in fiber orientation) to tensile modulus and tensile stress for fiber reinforced thermoplastic (FRP) in injection molding process can be validated.

在过去的两个世纪中，由于人口增长过快，人为污染严重影响了我们的环境，特别是对CO ₂排放。减少CO ₂排放问题，一种有效的解决方案是使用轻质材料（例如纤维增强塑料（FRP））代替运输车辆制造中的金属。但是，由于塑料基质内部纤维的增强功能非常复杂，因此不容易可视化和管理。具体而言，从纤维的微观结构到最终产品的物理性能的联系远非我们所理解。在这项研究中，我们提出了一个基准，其中包含三个基于ASTM D638且具有不同浇口设计的标准样品。该系统用于通过数值模拟和实验研究来研究纤维的微观结构和相关的机械性能。结果表明，所有三个ASTM标准样品的拉伸性能（包括拉伸模量和拉伸应力）都可以在纤维外观上得到显着改善。此外，还研究了基于浇口设计的与短纤维的微观结构相关的成品零件的拉伸性能变化。具体而言，模型I的拉伸模量和强度大于模型II，而模型III由于其双浇口效应而远远小于其他模型。模型I的拉伸模量和强度大于模型II的原因是由于某种进入效应。入口效应将进一步提供流动引起的纤维取向以熔化，然后增强模型I的拉伸性能。为证实这一点，进行了一系列的模拟和实验研究。具体而言，使用CAE预测纤维取向分布，并使用Micro-CT扫描和Avizo软件进行的图像分析进行验证。因此，可以验证从纤维微观结构特征（特别是在纤维取向方面）与纤维增强热塑性塑料（FRP）在注塑过程中的拉伸模量和拉伸应力之间的相关性。