碳-芳纶混杂正交三向复合材料疲劳性能实验研究

采用三维机织工艺结合树脂传递模塑(RTM)技术制备了两种碳-芳纶混杂正交三向复合材料,即z向纱均采用芳纶纤维,经纬纱分别为炭纤维和经纬纱间隔排列炭纤维和芳纶纤维的混杂正交三向复合材料,以恒定应力幅值、应力比和频率,开展了复合材料经向拉伸疲劳性能试验,通过与炭纤维复合材料的对比,分析了碳-芳纶混杂方式对复合材料拉伸疲劳性能(疲劳寿命、疲劳破坏特征和疲劳后强度/刚度)的影响。当z向纱选用芳纶纤维,面内经纬纱为炭纤维的混杂复合材料经向拉伸疲劳寿命表现出正混杂效应;当进一步混入芳纶纤维,面内经纬纱为炭纤维和芳纶纤维间隔排列正交三向复合材料疲劳寿命表现为负混杂效应,对疲劳刚度损失有一定的抑制作用。可见,炭纤维正交三向复合材料中引入芳纶纤维,对其复合材料拉伸疲劳性能有重要影响,通过设计纤维混杂方式和混杂比例可进一步提高复合材料疲劳性能。

Experimental study on the tensile fatigue properties of carbon-aramid hybrid 3D orthogonal composites

Two kinds of carbon-aramid hybrid 3D orthogonal composites were prepared by using 3D weaving and RTM process. They are hybrid 3D orthogonal composites with aramid fiber as z direction yarn or carbon fiber as warp and weft (HZK),and the other ones with carbon-aramid fiber as warp and weft interval arrangement (HCK).The fatigue testing in the warp direction was con-ducted by applying an alternating tensile stress with constant stress amplitude,stress ratio and frequency. Compared with carbon fi-ber 3D orthogonal composites ( NHC) ,the tensile fatigue behavior ( fatigue life,damage feature and fatigue strength and stiffness) were analyzed experimentally.The results show that the fatigue life of HZK hybrid composites has the positive hybrid effect,while that of the HCK hybrid composites is negative.The HCK hybrid composites have certain inhibition effect on the fatigue stiffness loss. Therefore,the hybridization of carbon-aramid has an impact on the fatigue of carbon fiber composites.Moreover, the hybrid mode and hybrid ratio of carbon and aramid fiber can be tailored to further improve the fatigue properties of the composites.