The relationship between the thickness and flexural strength of unidirectional carbon fiber reinforced polymers manufactured through VARI

Abstract

The three-point bending tests at constant loading rates and constant span to thickness ratio were carried out to investigate the behavior and effect of thickness on unidirectional carbon fiber reinforced polymers (UD-CFRPs). The specimens were manufactured in different thicknesses through the vacuum assisted resin infusion (VARI) technique. Experiments were conducted at strain rate of 0.01 s−1 with constant span-to-thickness ratio of 40:1 according to ASTM D7264/D7264M-15 test standard. It was observed from the results that the thicker the laminate, the higher the peak force, and less strain the structure can withstand. The failure stress and strain curves revealed that the less thick the specimen is, the higher the stress and strain the specimen will endure. Failure modes and microstructures of specimens were observed to analyze and explain the underlying mechanism of reinforcing effect. It was observed that the specimens failed due to individual layer delamination and was found to be the main mechanism for avoiding catastrophic failure and interfacial damage of the sandwich specimen.