含低速冲击损伤复合材料层合板剩余压缩强度及疲劳性能试验研究
Experiment research on residual compressive strength and fatigue performance of composite laminates with low velocity impact damage
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摘要: 对T300/QY8911复合材料层板进行了低速冲击、 冲击后压缩以及冲击后疲劳试验研究。通过对冲击后的层板进行目视检测和超声C扫描获得了层板受低速冲击后的若干损伤特征; 在压-压疲劳试验中, 测量了损伤的扩展情况。讨论了冲击能量与损伤面积以及冲击后剩余压缩强度的关系, 分析了含冲击损伤层合板在压缩载荷及压-压疲劳载荷下的主要破坏机制。结果表明, 低速冲击损伤对该类层板的强度和疲劳性能影响很大, 在3.75 J/mm的冲击能量下, 层板剩余压缩强度下降了65%; 在压-压疲劳载荷作用下, 其损伤扩展大致可分为两个阶段, 占整个疲劳寿命约60%的前一阶段损伤扩展较为缓慢; 而疲劳寿命的后半阶段损伤则开始加速扩展, 并导致材料破坏。Abstract: Residual compressive strength and compression-compression fatigue tests of T300/QY8911 laminates with low velocity impact damage were studied. The damage characteristic of impacted laminates was measured by visual check and ultrasonic C-scan. Damage propagation in compression-compression fatigue test was measured in detail. The relationship between damage area, compressive strength after impact (CAI) and impact energy was discussed. The major damage mechanism of damaged composites under compressive or compression-compression fatigue load was also analyzed. The results show that low velocity impact damage has a great effect on the compressive strength and fatigue performance of laminates, residual compressive strength reduces by 65% when the laminates is impacted by energy of 3.75 J/mm. The damage propagation under compression-compression fatigue load can divide in two stages, on the first 60% of fatigue life, damage grows slowly; and on the rest of fatigue life, damage has a rapid growth.