Stacking Sequence Effect on the Fracture Behavior of Narrow L-Shaped Cross-Ply Laminates: Experimental Study

The stacking sequence effect of narrow L-shaped laminates on the fracture mode was studied. Two laminate stacking sequences were designed to analyze different fracture modes. The sequence layup J, i.e., [0/904/02/902/02/902/02/90]s trends to highlight the matrix fracture mode, whereas the stacking sequence layup I, i.e., [04/90/03/90/02/902/02/90]s tends to highlight the delamination mode. Load–deflection curves and fracture modes for these stacking sequences under a four-point bending loads were recorded and compared with the plane-strain empirical formula and experimental results. The results show that the stacking sequence has a significant effect on the initial fracture mode of narrow L-shaped laminar composites. Layup J shows matrix-dominant initial fracture due to the weak resistance of inner 90° plies to tangential tensile stresses, whereas layup I experiences delamination-dominant initial failure. The edge effect has a great influence on the fracture mode of layup J-like specimens, whereas it is very weak for layup I-like ones. The stacking sequence also influences the carrying capacity; a maximum fracture load of layup J is apparently lower than that of layup I, by about 23%.