Effect of Ply Stacking and Fiber Volume Fraction on ILSS of Woven GFRP Laminates

This paper evaluates the effect of the ply stacking sequence and fiber volume fraction on the interlaminar shear strength of glass fiber reinforced polymer (GFRP) laminates. Eight- and 6-ply laminates had two different ply stacking sequences, making them asymmetric and symmetric laminates, while fiber content was higher in case of 8-ply laminates. GFRP laminates were fabricated by hand layup technique followed by press molding. Fiber volume fractions were calculated 56% and 45% for 8- and 6-ply laminates, respectively. Samples were prepared according to the ASTM-D-2344 standard. Tests were performed on the computer-controlled universal testing machine (UTM) with 50 KN load cell at a crosshead speed of 1 mm/min. Results show that the interlaminar shear stress is higher for symmetric laminates compared with asymmetric laminates. It was also found out that an increase in fiber volume fraction decreases ILSS, thus depicting it is a matrix-dominated property. Weibull distribution analysis of the samples was performed in order to examine the static stability of FRP laminates. Laminates with high ILSS had less scattering from the mean value.