Influence of Experimental Loading Rate and Fabrication on the Synthetic Fiber Reinforced Polymeric Skin of an Advanced Composite

Influence of loading rate and fabrication methodology of synthetic fiber reinforced polymeric skin of advanced composite is studied experimentally with different loadings at 0°, 90°, and 45° direction to the weft (longitudinal) or 1- direction at several loading rates for the ultimate tensile strength, Poisson’s ratio, and modulus of rigidity. Hand lay-up and vacuum-assisted resin transfer methodology (VARTM) were used for fabrication. The skins of sandwich composite with multidirectional fiber and epoxy resins were fabricated by feeding resin along the 1-direction. The tensile modulus along 1-, at warp, and at 45° to 1-direction were determined. There were 275 and 550 threads along the weft warp directions, respectively. The laminate samples were tested for loading rates of 1.9, 2.4, and 4.8 mm per minute in all three directions. The tensile modulus of elasticity in weft as well as warp directions were more for VARTM-fabricated specimens than for those fabricated through the hand lay-up method for a loading rate of 1.9 mm/min. However, in the case of studies on VARTM-casted specimens, the effect of different loading rates revealed that the stiffnesses slightly increased for higher cross-head speeds of the universal testing machine, applying tensile loads along weft directions. The maximum standard deviation (relative) of 4.82% was noted for tensile stiffness along the weft direction. The variation in results for tensile modulus and different loading rates along the warp direction was insignificant. Similarly, the variation in major Poisson’s ratios for various loading rates was insignificant for specimens fabricated by VARTM.