Prediction of mechanical properties of 3-D braided composite using CAD system

The geometrical and mechanical properties of three-dimensionally braided glass/epoxy composite were investigated using the CAD system. The three-dimensional (3-D) yarn path was described using third order spline curves referring to our previous work about the circular braided preform. The CAD system for the flat plate-shaped composite was developed by modifying that for the circular preform. The 3-D braided glass/epoxy composite was manufactured using the resin transfer molding (RTM) process and the tensile modulus in the axial as well as transverse directions were measured. The tensile modulus of the composite was predicted using the developed CAD system adopting the volume averaging method. The prediction exhibited good agreement with the experimental results. The effects of pitch length and the number of layers on the mechanical properties of braided composite were successfully estimated using the CAD system.