Abstract
With the aim of finding new materials having high stiffness to density ratio, carbon fiber composite materials have gained popularity as alternatives to traditional high-stiffness and high-density materials. This work investigates the dependency on strain rate of some mechanical properties of unidirectional carbon fiber reinforced epoxy, CFRE. The composite laminates were fabricated at fiber orientations of 0° (dubbed type 1) while others at 90° (dubbed type 2). Statistical analysis (using Minitab® software) has been applied to determine the statistical significance (modulus at confidence interval varying from 5% to 10%) of the effect of strain rate on composite material response and strength. Both type 1 and type 2 composite laminates were tested at several levels of flexural strain rates varying from 1.8*10−5 s−1 to 7.8*10−3 s−1. For type 1 and type 2 laminates, the flexural fracture stress values were found to increase around 4.5% and 8.6%, respectively, for the studied range of strain rates. It was also found that the flexural modulus of elasticity increased for both 0° and 90° increase in order of 5% and 10%, respectively, for type 1 and type 2 laminates over the strain rate range. This was evidenced by the increase in the variance of the experimentally collected flexural strength values with increasing operating strain rate.
