Effect of Z-fiber orientation on the bending behavior of sandwich-structured composite: Numerical and experimental study

摘要

Sandwich-structured composites are designed to improve through-the-thickness mechanical properties. In this paper, the effect of Z-fiber orientation on the bending behavior of sandwich-structured composites reinforced with weft-knitted spacer fabrics was studied numerically and experimentally. A new mathematical model was generated for geometry of pile yarns. Using the generated model, different orientations of Z-fibers were simulated in ABAQUS software. To investigate the effect of Z-fiber orientation, different structures of pile yarns designed using the gaiting and feeding ratio of pile yarns and layers. Composites with different Z-fiber orientations of reinforcement were fabricated. Three-point bending test was carried out on the prepared samples. The results of experimental and numerical investigations showed that the pattern of reinforcements that creates different orientations of Z-fibers with various heights and angles considerably influences the bending behavior of sandwich-structured composites. The maximum von Mises stress occurs in Z-fibers when the composites are bent in the transverse direction, but the maximum von Mises stress is created in the layers when the composites are bent in the longitudinal directions. Consequently, in the transverse direction, Z-fibers play the major role in the bending behavior of sandwich-structured composites, whereas in the longitudinal direction, the layers play the main role.