Effect of transverse compression on the residual tensile strength of ultrahigh molecular weight polyethylene (Dyneema® SK-76) yarns

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.