This work examines the experimental and analytical investigation of impact on the carbon/epoxy laminates of various stacking sequence. The impact tests were carried out by using gas gun equipped with high-speed camera. Projectile velocities selected were 80 m/s and 30 m/s where 80 m/s was above ballistic limit velocity and 30 m/s was below ballistic limit velocity. The impact process was recorded with high-speed camera which facilitated to identify different energy absorbing mechanisms. High-speed images were also used to measure pre-impact and post-impact velocities of the projectile accompanied by photo diode and aluminum foil method. Total energy absorbed by the laminates, which is the difference between pre-impact and post-impact kinetic energy of the projectile, was calculated for the laminates with different stacking sequences. Damage extent in the laminates of different stacking sequences were also assessed by C-Scan of the laminates. Then effect of stacking sequences on damage extent and energy absorbing capacity was established. An analytical model was proposed to predict the residual velocity of the projectile at above ballistic limit velocity, which was based on the total energy absorbed by different energy absorption mechanisms. The analytical model was validated with experimental results for different stacking sequences. Additionally, effect of fiber orientation on damage shape at below ballistic limit velocity was also studied.

中文翻译：

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不同堆叠顺序碳纤维增强复合材料的冲击损伤评估

这项工作检查了对各种堆叠顺序的碳/环氧树脂层压板影响的实验和分析研究。冲击试验采用装有高速摄像机的气枪进行。选择的弹丸速度为 80 m/s 和 30 m/s，其中 80 m/s 高于弹道极限速度，30 m/s 低于弹道极限速度。撞击过程是用高速摄像机记录的，这有助于识别不同的能量吸收机制。高速图像还用于测量伴随光电二极管和铝箔方法的弹丸的预撞击和撞击后速度。对于不同堆叠顺序的层压板，计算了层压板吸收的总能量，即弹丸的冲击前和冲击后动能之差。不同堆叠顺序的层压板的损坏程度也通过层压板的 C-Scan 评估。然后建立了堆叠顺序对损伤程度和能量吸收能力的影响。提出了一种基于不同能量吸收机制吸收的总能量来预测弹丸在弹道极限速度以上的剩余速度的分析模型。分析模型通过不同堆叠序列的实验结果进行了验证。此外，还研究了纤维取向对低于弹道极限速度时损伤形状的影响。提出了一种基于不同能量吸收机制吸收的总能量来预测弹丸在弹道极限速度以上的剩余速度的分析模型。分析模型通过不同堆叠序列的实验结果进行了验证。此外，还研究了纤维取向对低于弹道极限速度时损伤形状的影响。提出了一种基于不同能量吸收机制吸收的总能量来预测弹丸在弹道极限速度以上的剩余速度的分析模型。分析模型通过不同堆叠序列的实验结果进行了验证。此外，还研究了纤维取向对低于弹道极限速度时损伤形状的影响。