干燥温度对CFRP力学性能的影响及作用机理

采用 2 种环境温度( 70、85 ℃)对碳纤维增强树脂基复合材料( CFRP)层合板进行干燥处理,并对 CFRP 层合板分别进行拉伸、压缩和剪切实验,研究了中温干燥条件对 CFRP 层合板力学性能的影响,通过扫描电子显微镜和红外光谱,分析了中温干燥环境对 CFRP 层板的影响机理;通过最小二乘法拟合方法,提出了干燥环境下 CFRP 层合板力学性能的预测公式。研究结果表明:与未经干燥的试样相比,经中温干燥环境处理的 CFRP 层板的 90°拉伸强度增加 24. 99%,± 45°剪切强度下降 12. 92%;中温干燥环境对 CFRP 层合板力学性能的影响是由后固化作用和复合材料内部的热应力共同决定的,在中温干燥环境下,CFRP 层合板未发生化学结构变化,CFRP 层合板中的环氧基发生了进一步交联,环氧基树脂被后固化增强;拟合建立的不同干燥条件下的力学性能预测公式与实验结果基本一致。

Effect of Dried Temperatures on Mechanical Properties and Mechanism of CFRP

Carbon fiber reinforced plastics (CFRP) was dried under two different temperatures (70、85 ℃). Tensile, compressive and shear tests were carried out to study the effects of middle temperature dried conditions on the mechanical behaviors of CFRP laminates. The effect of middle temperature dried environments on CFRP laminates was analyzed by scanning electron microscopy and infrared spectroscopy. A formula which could predict the mechanical properties of CFRP laminates in dried environments was proposed by least square method. The results showed that compared with the un-dried samples,the 90° tensile strength of the CFRP laminates treated by the middle temperature dried environments increased by 24. 99%,and the ± 45°shear strength of treated CFRP laminates decreased by 12. 92%. The effect of middle temperature dried environments on the mechanical properties of CFRP laminates was determined by both the post curing and the thermal stress in the composite. In the middle temperature dried environments,there was no chemical structure change in the CFRP laminates. The epoxy groups in the CFRP laminates were further crosslinked,the epoxy resin was post-curing strengthened. The formula of mechanical behavior prediction in different dried conditions was basically consistent with the experimental results.