Ballistic impact induces complex stress states on fiber-based armor systems. During impact fibers undergo multiaxial loading which includes axial tension, axial compression, transverse compression, and transverse shear. Transverse compression induced by the projectile leads to permanent deformation and fibrillation of fibers resulting in degradation of material tensile strength. Previous work (Sockalingam et al. Textile Res. J 2018) has shown a reduction of 20% in the tensile strength of Dyneema® SK76 single fibers subjected to 77% nominal transverse compressive strains. Experimental investigation of quasi-static transverse compression on Dyneema® SK-76 yarns, unconstrained in the lateral direction, indicate an average of 4% reduction in tensile strength of yarns compressed to 77% nominal strains. In this work we use finite element modeling techniques to understand the difference in residual tensile strength between single fibers and yarns observed in laterally unconstrained transverse compression experiments. Finite element study of the transverse compression response of single fibers and yarns indicate that local strains developed in fibers within the yarn are much lower than the local strains developed in single fibers subjected to a given nominal strain and may explain the less reduction in strength observed in yarns.

弹道冲击会在基于纤维的装甲系统上引起复杂的应力状态。在冲击期间，纤维经受多轴载荷，包括轴向张力，轴向压缩，横向压缩和横向剪切。弹丸引起的横向压缩导致纤维的永久变形和原纤化，从而导致材料抗张强度降低。先前的工作（Sockalingam等人，Textile Res。J 2018）表明，经受77％标称横向压缩应变的Dyneema®SK76单纤维的拉伸强度降低了20％。对Dyneema®SK-76纱线进行准静态横向压缩的实验研究表明，在横向方向上不受限制，压缩至77％标称应变的纱线的拉伸强度平均降低了4％。在这项工作中，我们使用有限元建模技术来了解在横向无限制横向压缩实验中观察到的单纤维和纱线之间的残余拉伸强度的差异。对单根纤维和纱线的横向压缩响应的有限元研究表明，在给定标称应变的情况下，纱线内纤维中产生的局部应变远低于单纤维中产生的局部应变，并且可以解释观察到的强度降低幅度较小。纱线。