Xu Dandan, Ma Huibin, Guo Yu
College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou 310023, China.
State Key Laboratory of Clean Energy Utilization, Department of Engineering Mechanics, Zhejiang University, Hangzhou 310027, China.
Materials (Basel). 2023 Mar 29;16(7):2712. doi: 10.3390/ma16072712.
The effects of fiber shape on the mechanical responses of fiber assemblies under compression, tension, and shear deformations are numerically investigated using the discrete element method (DEM). Simulations of the compression of ring-shaped fibers are consistent with experimental results, verifying the discrete element method code. In the compressive tests of S-shaped fibers, pressure exhibits a nonmonotonic dependence on fiber curvature; while in the tensile tests, yield tensile stress generally decreases with increasing fiber curvature. In the shear tests, yield shear stress decreases with increasing fiber curvature for the S-shaped fibers, and the smallest yield shear stresses and the smallest coordination numbers are obtained for U-shaped and Z-shaped fibers. It is interesting to observe that for the assemblies of various fiber shapes, yield shear stress increases with increasing maximum Feret diameter of the fibers, which characterizes the largest dimension of a fiber between two parallel tangential lines. These novel observations of the effects of fiber shape provide some guidelines for material designs with the fibers.
采用离散元法（DEM）对纤维形状对纤维组件在压缩、拉伸和剪切变形下力学响应的影响进行了数值研究。环形纤维压缩模拟结果与实验结果一致，验证了离散元法程序。在S形纤维的压缩试验中，压力对纤维曲率呈现非单调依赖性；而在拉伸试验中，屈服拉伸应力通常随纤维曲率增加而降低。在剪切试验中，S形纤维的屈服剪切应力随纤维曲率增加而降低，U形和Z形纤维的屈服剪切应力和配位数最小。有趣的是，对于各种纤维形状的组件，屈服剪切应力随纤维最大费雷特直径的增加而增加，该直径表征了纤维在两条平行切线之间的最大尺寸。这些关于纤维形状影响的新观察结果为纤维材料设计提供了一些指导。
