Visualization and numerical analysis of fiber orientation on weld line in processing for fiber-reinforced composite materials

纤维增强复合材料加工过程中焊缝纤维取向的可视化和数值分析

• 批准号: 13650747
• 负责人: YASUDA Kazunori
• 金额: $ 1.41万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13650747/
• 关键词: Concentrated fiber suspension; Circular obstacle; Slit channel; Refractive-index-matching; Birefringence; Weld line; Fiber orientation; Concentration distribution of fiber; 濃度分布; 円柱障害

Flow-induced fiber orientation and concentration distributions were measured in a concentrated fiber suspension (CFS) and a dilute one (DFS). The channel has a thin slit geometry containing a circular cylinder.In the previous work, many researchers have qualitatively studied fiber orientation and concentration distributions in injection-molded products of fiber-reinforced plastics. In the present work, however, they are quantitatively estimated by direct observation of fibers in the concentrated suspension flow.For the CFS, some fibers rotate in an expansion part between the channel wall and the circular cylinder, and the fiber orientation becomes almost random state. On the other hand, fibers are perfectly aligned along the flow direction owing to the elongational flow near the centerline downstream of the cylinder. The fiber concentration has a flat distribution except near the channel wall and the centerline.For the DFS a minimum in the fiber concentration distribution was clearly observed on the centerline, and two peaks beside the centerline and near the channel wall. This characteristic distribution is caused by the fiber-wall and fiber-cylinder interactions. It is found that the obstacle such as the circular cylinder in the channel significantly affects the fiber orientation downstream of the obstacle for the CFD, while it affects the fiber concentration distribution for the DFS.

在浓纤维悬浮液（CFS）和稀纤维悬浮液（DFS）中测量了流动诱导的纤维取向和浓度分布。在以往的工作中，许多研究者定性地研究了纤维增强塑料注射成型制品中纤维的取向和浓度分布。对于CFS，部分纤维在通道壁面与圆柱体之间的膨胀段内旋转，纤维取向几乎呈随机状态。另一方面，由于圆筒下游中心线附近的拉伸流动，纤维沿着流动方向沿着完美排列。纤维浓度分布除靠近通道壁面和中心线处外呈平坦分布，在中心线处纤维浓度分布最小，在通道壁面和中心线附近有两个峰值。这种特征分布是由纤维-壁和纤维-柱体相互作用引起的。结果表明，对于CFD，通道中的圆柱体等障碍物对障碍物下游的纤维取向有显著影响，而对于DFS，障碍物对纤维浓度分布有显著影响。