Composite sandwich structures are highly proven materials that provide high strength to weight ratio. However research works are still being carried out in the area of impact characteristics of sandwich composites. Th...Composite sandwich structures are highly proven materials that provide high strength to weight ratio. However research works are still being carried out in the area of impact characteristics of sandwich composites. This paper provides a better understanding on the effect of core density and core thickness of sandwich panels subject to low velocity drop test. Specific energy absorption capacity of sandwich panels is obtained and factors affecting the same are explored with facings made of woven glass fiber laminates and polyurethane foam core with three different densities of 70 Kg/m3, 100 Kg/m3, 200 Kg/m3.展开更多
多孔夹芯结构因优异的比强度、比刚度而广泛应用于爆炸冲击防护领域,然而目前与爆炸相关的研究主要集中在小当量爆炸加载下夹芯结构的失效机制,实际大当量加载场景下的吸能特征研究较为少见。为更好指导工程应用,设计了三种夹芯材料(泡...多孔夹芯结构因优异的比强度、比刚度而广泛应用于爆炸冲击防护领域,然而目前与爆炸相关的研究主要集中在小当量爆炸加载下夹芯结构的失效机制,实际大当量加载场景下的吸能特征研究较为少见。为更好指导工程应用,设计了三种夹芯材料(泡沫铝、边长3 mm及边长10 mm的蜂窝铝)在不同夹芯构型(单层夹芯、两层夹芯)及不同面板/夹层板/背板厚度下的十种夹芯结构,并对上述夹芯结构开展了0.5 kg TNT和1 kg TNT当量爆炸加载实验,分析了不同当量下夹芯结构的整体变形特征,探讨了夹芯材料、夹芯构型等因素对吸能防护的影响。实验结果表明:爆炸加载下,泡沫夹芯结构及蜂窝夹芯结构均可通过芯体材料的大幅压缩变形吸收转换能量,但整体而言蜂窝结构的变形均匀化更好;芯体吸能效率的发挥一方面与自身的比压缩强度相关,另一方面也与表层面/背板的强度及刚度相关,在实际应用时需优化匹配芯体的压缩强度与面/背板的强度及刚度,保证芯体材料可获得最大程度的压缩,发挥其吸能优势;实验中发现双层夹芯结构在吸能防护性能上优于等面密度的单层夹芯结构,即在等面密度的情形下,通过对内部芯体的合理结构优化是提升结构整体吸能防护效果的有效途径。该研究可以为实际应用中的防护结构设计提供更多参考数据。展开更多
Effects of face-sheet thickness and core thickness of sandwich panels, and shape of projectiles on the penetration resistance of sandwich panels were discussed, while typical pen- etration failure modes were presented...Effects of face-sheet thickness and core thickness of sandwich panels, and shape of projectiles on the penetration resistance of sandwich panels were discussed, while typical pen- etration failure modes were presented. It was shown that the anti-penetration performance of sandwich panels was enhanced with the increase of face-sheet or core thickness; The penetration resistance of sandwich panels was shown to be strongest to blunt-shaped projectile impacts, weaker to hemispherical-nose-shaped projectile impacts, and weakest to conical-shaped projectile impacts. The corresponding numerical simulation was carried out using the finite element code LS-DYNA V970. Numerical results showed that the penetration time decreased with the increase of projectile impact velocity.展开更多
文摘Composite sandwich structures are highly proven materials that provide high strength to weight ratio. However research works are still being carried out in the area of impact characteristics of sandwich composites. This paper provides a better understanding on the effect of core density and core thickness of sandwich panels subject to low velocity drop test. Specific energy absorption capacity of sandwich panels is obtained and factors affecting the same are explored with facings made of woven glass fiber laminates and polyurethane foam core with three different densities of 70 Kg/m3, 100 Kg/m3, 200 Kg/m3.
文摘多孔夹芯结构因优异的比强度、比刚度而广泛应用于爆炸冲击防护领域,然而目前与爆炸相关的研究主要集中在小当量爆炸加载下夹芯结构的失效机制,实际大当量加载场景下的吸能特征研究较为少见。为更好指导工程应用,设计了三种夹芯材料(泡沫铝、边长3 mm及边长10 mm的蜂窝铝)在不同夹芯构型(单层夹芯、两层夹芯)及不同面板/夹层板/背板厚度下的十种夹芯结构,并对上述夹芯结构开展了0.5 kg TNT和1 kg TNT当量爆炸加载实验,分析了不同当量下夹芯结构的整体变形特征,探讨了夹芯材料、夹芯构型等因素对吸能防护的影响。实验结果表明:爆炸加载下,泡沫夹芯结构及蜂窝夹芯结构均可通过芯体材料的大幅压缩变形吸收转换能量,但整体而言蜂窝结构的变形均匀化更好;芯体吸能效率的发挥一方面与自身的比压缩强度相关,另一方面也与表层面/背板的强度及刚度相关,在实际应用时需优化匹配芯体的压缩强度与面/背板的强度及刚度,保证芯体材料可获得最大程度的压缩,发挥其吸能优势;实验中发现双层夹芯结构在吸能防护性能上优于等面密度的单层夹芯结构,即在等面密度的情形下,通过对内部芯体的合理结构优化是提升结构整体吸能防护效果的有效途径。该研究可以为实际应用中的防护结构设计提供更多参考数据。
基金Project supported by the National Natural Science Foundation of China(Nos.11172196,11572214 and 11402216)the Top Young Academic Leaders of Higher Learning Institutions of Shanxi and the opening foundation for State Key Laboratory of Explosion Science and Technology and the State Key Laboratory of Traction Power(No.2014TPL T09)
文摘Effects of face-sheet thickness and core thickness of sandwich panels, and shape of projectiles on the penetration resistance of sandwich panels were discussed, while typical pen- etration failure modes were presented. It was shown that the anti-penetration performance of sandwich panels was enhanced with the increase of face-sheet or core thickness; The penetration resistance of sandwich panels was shown to be strongest to blunt-shaped projectile impacts, weaker to hemispherical-nose-shaped projectile impacts, and weakest to conical-shaped projectile impacts. The corresponding numerical simulation was carried out using the finite element code LS-DYNA V970. Numerical results showed that the penetration time decreased with the increase of projectile impact velocity.
