Abstract

Sandwich composites with polymeric open-celled foams or honeycomb structures as core materials have been used widely in low-weight naval, aerospace and structural applications in the past. One major drawback of such foams is skin-core debonding. To overcome this, core materials with the same matrix as the skin are studied in this paper. Sandwich composites with fibre composite skins and a hollow glass particle-filled syntactic foam core are fabricated and tested under ballistic impact loading. Both the constituents have an epoxy matrix and are fabricated using a co-curing method which improves the skin-core debonding considerably. Parameters such as ballistic limit and energy absorbed by the samples are obtained for different core volume fractions and varying skin thicknesses. The effect of skin layup sequence has also been studied. It is found that samples with thicker back skins have better impact-resistant properties. The external and internal damage in the samples subject to different impact velocities is studied by visual means and CT scans. An energy-based analytical model is used to predict the ballistic limit of the samples, and to study the individual energy-absorption modes. The evolution of the contribution of the modes with time as well as the velocity profile of the projectile as it penetrates the composites are also obtained from the model. The experiments and the model show comparable ballistic limit results.

摘要

过去，以聚合物开孔泡沫或蜂窝结构作为芯材的夹层复合材料已广泛用于轻质海军、航空航天和结构应用。这种泡沫的一个主要缺点是皮芯脱粘。为了克服这个问题，本文研究了与表皮具有相同基质的芯材。在弹道冲击载荷下制造和测试具有纤维复合材料表皮和中空玻璃颗粒填充复合泡沫芯的​​夹层复合材料。这两种成分都具有环氧树脂基体，并使用共固化方法制造，可显着改善皮芯剥离。对于不同的核心体积分数和不同的蒙皮厚度，获得了诸如弹道极限和样品吸收的能量等参数。还研究了皮肤铺层顺序的影响。发现具有较厚背皮的样品具有更好的抗冲击性能。通过视觉手段和CT扫描研究了样品在不同冲击速度下的外部和内部损伤。基于能量的分析模型用于预测样品的弹道极限，并研究单个能量吸收模式。模型的贡献随时间的演变以及弹丸穿透复合材料时的速度分布也从模型中获得。实验和模型显示出可比较的弹道极限结果。基于能量的分析模型用于预测样品的弹道极限，并研究单个能量吸收模式。模型的贡献随时间的演变以及弹丸穿透复合材料时的速度分布也从模型中获得。实验和模型显示出可比较的弹道极限结果。基于能量的分析模型用于预测样品的弹道极限，并研究单个能量吸收模式。模型的贡献随时间的演变以及弹丸穿透复合材料时的速度分布也从模型中获得。实验和模型显示出可比较的弹道极限结果。