A study on mechanical properties of carbon fiber reinforced plastics by three-point bending testing and transverse static response

CFRP composite materials are used increasingly in various fields such as space and aviation industry, architectural structures, shipbuilding materials, sporting goods, and interior and structural materials of automobiles due to the excellence of mechanical characteristics as well as light weight, heat resistance, and control characteristics. Stacking plates of CFRP composite materials, which are used increasingly because of these unique characteristics, have the properties of uneven quality and anisotropic nature unlike general metallurgical materials as they are stacking plates of composite materials in the combination of different types of materials. Hence, specimens of stacking plates of CFRP composite materials were manufactured by changing orientation angles in three kinds of quasi-isotropic plies such as (0°/45°/90°/−45°)6S, (03°/453°/903°/−453°)2S, and (06°/456°/906°/−456°)S and also in three kinds of cross plies such as (0°/90°/0°/90°)6S, (03°/903°/03°/903°)2S, and (06°/906°/06°/906°)S. In this study, it was possible to obtain the following results by carrying out three-point bending testing and transverse bending test in order to find out mechanical characteristics according to orientation angles by stacking in six different types with the changes of stacking composition methods of CFRP composite materials. As interface number increases, the maximum load was increased and specimens stacked in quasi-isotropic plies had large operations in its maximum load rather than cross plies. Therefore, it was found that it is correct to stack in quasi-isotropic plies when composing stacking of CFRP composite materials.