Effects of compaction force and heating temperature of prepreg on composite mechanical properties during fiber placement process

The orthogonal experiment of three factors-four levels and a single factor experiment were conducted to evaluate the effect of compaction force, heating temperature of prepreg, and tool temperature on the mechanical properties of the laminar composite fabricated by fiber placement. The testing results of the mechanical properties and the microstructure images obtained through SEM and light microscope show that the effect of compaction force and heating temperature on interlaminar shear-strength (ILSS) is significant, while the effect of the tool temperature on ILSS is not obvious. The comprehensive mechanical properties of laminar composite are the best at 600 N level of the compaction force, 30℃ of the heating temperature, and 18℃ of the tool temperature. The microstructure results show that the distribution of resin in the cured composite becomes more and more uniform, and the thickness of interlaminar resin-rich area decreases with the increase of compaction force and heating temperature, and accordingly the strong ILSS. When the heating temperature is over 40℃, the distribution of resin in the cured composite material becomes non-uniform because of the action of compaction force, the thickness of interlaminar resin-rich area increases gradually, which results in the decrease of ILSS.