自动铺丝用预浸窄带的质量分析及其影响因素

Quality analysis of prepreg tow for automated fiber placement and its influencing factors

近年来随着自动铺丝技术的快速发展和应用,对预浸窄带的需求量增加,但国内研究人员对有关预浸窄带质量的评价体系和分析方法尚未形成统一共识。本文采用多种方法对预浸窄带的质量进行了全面分析。通过图像法及称重法分析发现,国产窄带的宽度均匀性、接头处纤维平齐度、边缘断丝情况等分切质量均控制较好。研究了间歇式热压工艺和连续式辊压工艺对窄带接头质量的影响,通过拉剪强度和剥离强度分析发现,压接工艺温度和时间是影响其力学的关键因素,对比而言辊压工艺制得的接头性能较热压工艺具有更好的稳定性。同时,接头性能也受测试环境影响,其中环境湿度的作用大于温度。随着室温储存时间延长,窄带接头的力学性能先上升后下降,通过差热分析和红外光谱分析发现,这与界面处树脂的化学反应和固化程度增长密切相关。最后,对接头反复过辊后的疲劳损伤分析表明,接头处的拉剪强度随过辊温度、张力及圈数增加而下降.

In recent years, with the rapid development and application of automated fiber placement(AFP), the demand for prepreg tow has increased considerably. However, no consensus has been achieved on the evaluation system including the analysis method of the quality of prepreg tows in domestic. In this paper, the quality of prepreg slitting tows had been comprehensively analyzed by systematic methods. It was found that the slitting qualities of the domestic prepreg tows, including the width uniformity, the paralleling degree of fibers at the joint and the fiber fracture at the edge were all well controlled by using image and weight analysis. Effect of preparation methods,namely discontinuous hot-press process and continuous rolling process, on the quality of tow joint was investigated through the tensile-shear strength and peeling force testing. The results show that the process temperature and the time of duration are the key factors. In contrast, the joints made by continuous rolling process have more stable mechanical properties than those prepared by hot-press process. Meanwhile, the joint performance is impacted by the environmental conditions, wherein the humidity has more significant influence than the test temperature. With the prolongation of storage at room temperature, the mechanical properties of the joints first increased and then decreased. The DSC and IR characterization indicates that the property changes relate closely to chemical reactions and increasing curing degree of the resin matrix at the interface. The fatigue performance of the joint was tested by repeated roller passing and subsequent damage analysis. It reveals that the tensile-shear strengths of the fatigued joints decrease with increasing roller temperature, higher tension and more turns.