纤维铺放压紧力及预浸带加热温度对复合材料力学性能的影响

采用三因素四水平正交实验与单因素实验相结合, 通过力学性能测试及SEM和光学显微镜微观形貌观察研究了复合材料铺放过程中压紧力、 预浸带加热温度及芯模温度对复合材料力学性能的影响。实验结果表明: 压紧力与加热温度对层间剪切强度(ILSS)影响很大, 而芯模温度影响较小; 当压紧力为600 N、 预浸带加热温度为30℃、 芯模温度为18℃时, 复合材料综合力学性能达到最佳。微观形貌观察结果表明: 随着压紧力和预浸带加热温度升高, 纤维与树脂接触充分, 树脂与纤维分布均匀性较好, 层间富树脂区的厚度较小, ILSS逐渐增加; 但当预浸温度上升到40℃以后, 压紧力作用导致树脂与纤维的分布均匀性变差, 层间富树脂区的厚度较大, 从而导致ILSS下降。

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.