Transverse fatigue behavior analysis of symmetric and asymmetric glass fiber-reinforced laminates

This study examined the effect of interchanging the position of (0 degrees/90 degrees) and (+/- 45 degrees) angle ply around the midplane of an eight-layer symmetric [(0 degrees/90 degrees)/ (+/- 45 degrees)2/(0 degrees/90 degrees)]s and asymmetric woven glass fiber reinforced composite laminate having [(0 degrees/90 degrees)/(+/- 45 degrees)2/(0 degrees/90 degrees)//(+/- 45 degrees)/(0 degrees/90 degrees)2/(+/- 45 degrees)] and (+/- 45 degrees)/ (0 degrees/90 degrees)(2)/(+/- 45 degrees)//(0 degrees/90 degrees)/(+/- 45 degrees)(2)/(0 degrees/90 degrees) stacking sequence by means of flexure and fatigue test. The flexural and fatigue behavior of glass fiber- reinforced polymer (GFRP) laminates was analyzed as well. The GFRP laminates in varying stacking sequence having a volume fraction of 55 +/- 0.9% were subjected to fatigue and damage analysis under stress levels ranging from 90% to 50% of their ultimate flexural strength at f = 1 Hz, R = 0.1. Flexure and fatigue testing was done in accordance with ASTM D790/D790-17. The experiment results showed that the symmetric laminate with (0 degrees/90 degrees) ply at the compression and tension sides exhibited greater flexural strength (458.09 MPa) and fatigue lives as compared to the asymmetric A (352.70 MPa) and asymmetric B (272.89 MPa) laminates with (0 degrees/90 degrees) and (+/- 45 degrees) ply at the compression sides respectively. Microscopy and transmission light photography techniques were used to detect the damage behavior and capture the debond zone images. The correlation between the load-deflection curve, Wohler-curve, hysteresis loops, dynamic stiffness and debond zones was also examined with regard to different stacked laminates.