TENSILE STRENGTH OF CARBON FIBER TOW/EPOXY COMPOSITES WITH RESPECT TO THE MICROSTRUCTURE OF CARBON FIBER TOW

Abstract

Mechanical properties of continuous fiber reinforced composites are affected by the microstructure within carbon fiber (CF) tows. Herein, the effect of fiber distribution and fiber interlacing within CF tows on the tensile strength of CF tow/epoxy composites was studied. Three types of T700 grade CF tows with different microstructure and sizing treatment were prepared. Fiber distribution was evaluated by scanning electron microscope (SEM). Fiber volume fraction and minimum distance between CFs were calculated using numerical simulations. Quantitative evaluation of fiber interlacing was proposed, and it was applied to the three CF tows. Tensile strength of CF tow and CF tow/epoxy composites were measured, and compared with interfacial shear strength. Finally, two fiber interlacing models were proposed: core-shell structure model and uniform distribution model. Uniform distribution model with high fraction of 0° aligned CFs was advantageous to enhance the tensile strength of CF tow and the composites.