考虑时间和温度影响的复合材料开孔层板压缩失效分析

摘要

鉴于复合材料性能的时间-温度相关性, 对固化后的树脂基体(5228A)进行了动力学分析(Dynamic Mechanical Analysis, DMA), 得到了试验窗口中不同温度下的储能模量曲线片段, 利用封闭平移(Closed Form Shifting, CFS)方法对其进行扩展, 建立了主曲线并得到了曲线片段对应的平移因子.根据加速试验方法(Accelerated Testing Methodology, ATM), 分别以两种铺层的准各向同性开孔层板(CCF300/5228A)为研究对象, 建立了匀应变率(Constant Strain Rate, CSR)压缩强度主曲线.借助微距拍摄和超声波C扫描, 对其渐进损伤过程和不同温度下的破坏形貌进行了观测.结果表明:即使温度低于玻璃态转变温度, 树脂基体动态力学性能也会随时间的增加而降低;单层较厚的开孔层板压缩强度对时间和温度更加敏感, 而单层较薄的开孔层板则具有更好的损伤容限性能;温度升高、 加载速率降低时, 开孔层板压缩最终破坏主导因素从分层损伤趋于纤维屈曲.%Taking time-temperature dependent properties of composites into consideration, storage modulus segments of cured 5228A resin was obtained within a certain experimental window by dynamic mechanical analysis (DMA) under different temperatures.Master curve was constructed by closed form shifting (CFS), which corresponding shift factors resulted from.Constant strain rate (CSR) compression master curves were established based on accelerated testing methodology (ATM), studying quasi-isotropic open-hole CCF300/5228A laminates of two kinds of layup.By means of macro photography and C-scan, the damage processes and failure modes were investigated under different temperatures.The results show that dynamic mechanical properties of resin decrease with the increasing time even though with temperature range below the glass transition temperature;strength of thicker-ply laminates is more sensitive to time and temperature changes, while thinner-ply ones possess better damage tolerance property;the dominant factor of final failure tends to be micro-bulking of fiber instead of delamination as temperature rises and loading rate decreases.