Investigating fiber cutting at the composite grid intersections on the mechanical performance of laminates

Cutting of fibers at the intersections could effectively mitigate problems associated with fiber accumulation in thick ribs of composite grids. However, the effectiveness varies according to the different rib cutting angles in the structure. Therefore, five different cutting samples with cutting angles of 30°, 45°, 60°, 75°, and 90° were prepared in this study. Concurrently, numerical model for the tensile and compressive behavior of samples with fiber cutting was established considering zero-thickness interface elements. The results indicated that as the cutting angle decreased, the compressive strength of the ribs gradually increased, while the changes in tensile strength were not significant. Two distinctive failure modes were identified, namely, delamination-dominant failure (observed in 90°, 75°, and 60° cutting specimens) and fiber-breakage-dominant failure (manifested in 45° and 30° cutting specimens). Finally, it was concluded that reducing the cutting angle between ribs can effectively enhanced compressive strength, and a slight improvement in tensile strength was seen when the angle was not less than 45°. These findings offer valuable insights for designing and manufacturing composite grid structures.