Variable Angle Tow placement is a way to steer individual curvilinear fibers. This work presents the assessment of tensile behavior of open-hole composite laminates with Variable Angle Tow reinforcement. A new multi-scale finite element method, consisting of a microscale unit cell model and a macroscale gradient property model, is developed to simulate Variable Angle Tow structures with various fiber trajectories. The tensile strength and the failure process of open-hole reinforced laminates with Variable Angle Tow reinforcement under tensile loading are predicted and analyzed. Experiments are also conducted to investigate reinforcing efficiency and failure modes of the open-hole laminates. The comparison of predicted and experimental results for the tensile strength and failure modes of T700/Epoxy laminates demonstrates clearly that the mechanical behavior of Variable Angle Tow structure can be simulated very well by the proposed multi-scale model. Moreover, it is found that the tensile strength of Variable Angle Tow laminates is closely related to the eccentricity and it reaches the maximum value only when the trajectories of curvilinear fibers keeps consistent with maximum principal stress trajectories of the open-hole plate.

中文翻译：

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使用通用梯度特性模拟方法评估开孔可变角度丝束复合材料的拉伸行为

可变角度丝束放置是一种引导单个曲线纤维的方法。这项工作介绍了对具有可变角度丝束增强材料的开孔复合层压板的拉伸性能的评估。开发了一种新的多尺度有限元方法，包括微尺度晶胞模型和宏观梯度特性模型，用于模拟具有各种纤维轨迹的变角丝束结构。预测和分析了在拉伸载荷作用下变角丝束增强开孔增强层合板的抗拉强度和破坏过程。还进行了实验以研究开孔层压板的增强效率和失效模式。T700/环氧树脂层压板的拉伸强度和失效模式的预测和实验结果的比较清楚地表明，所提出的多尺度模型可以很好地模拟可变角度丝束结构的力学行为。此外，发现变角丝束层合板的抗拉强度与偏心率密切相关，只有当曲线纤维的轨迹与开孔板的最大主应力轨迹保持一致时，才能达到最大值。