The effects of the single filament and the fiber tow test methods on mechanical properties of carbon fibers

The strength of the reinforcing fibers is the main factor affecting the strength of the composites، therefore، accurate method for measuring the strength is needed. There are two methods for determining the strength of the reinforcing fibers (e. g. carbon fiber). They are the methods of single filament and the fiber tow test (fibers impregnated with resin). The main goal of this research is to find the correct procedure of testing carbon fibers with two different methods of single filament and fiber tow test، so comparing the mechanical properties of two types of PAN based carbon fibers given by those methods. The fibers used in this research were two types of carbon fibers and their mechanical properties like tensile strength، tensile modulus، breaking strain and fracture energy were studied in both test methods. The results show that although the single filament test method is quite difficult but compared with the fiber tow test method gives higher values for tensile strength and fracture energy whereas lower value for tensile modulus and breaking strain.