Experimental study on the mechanical behavior of laminates made by fiber steering: influence of fiber angle and tow width

Abstract This work considers the effects of fiber trajectory and prepreg width on the material strength and failure behavior of variable stiffness composites. The test matrix was designed according to commonly used fiber placement trajectory and width of prepreg in engineering. Different trajectories were compared for tensile, compressive, bending, shear and CAI strengths. For tensile and compressive performance, curved ply specimens have varying degrees of decrease compared to straight ply specimens; For shear and bending performance, the optimal layup sequence is [±45/〈30|45〉]. For impact toughness, curved ply is significantly higher than straight ply, and the CAI strength of straight ply exceeds that of curved ply. For variable stiffness laminate with different fiber angles and tow widths, the maximum tensile, compressive and CAI strengths were reduced by up to 66%, 56%, and 27%, and the maximum bending strength, shear strength and impact toughness were increased by up to 53%, 23%, and 10.3%, respectively. The increase in width of prepreg leads to an increase in defects between fiber bundles which weakens the tensile/compressive performance but enhances the shear/bending performance.