热膨胀工艺制备不同厚度泡沫夹芯复合材料的低速冲击性能

Low-velocity impact properties of foam sandwich composites with different thicknesses prepared via thermal expansion molding process

热膨胀工艺能够一体化成型各种泡沫夹芯复合材料。选择初始厚度为1 mm的可膨胀环氧泡沫预浸胶,通过控制模具型腔尺寸以控制不同成型压力制备4种不同厚度的泡沫夹芯板。以10 J和42 J冲击能量研究热膨胀工艺和芯材厚度对泡沫夹芯复合材料低速冲击性能的影响。通过ABAQUS有限元分析、超声C扫描对比试验数据分析了不同试样的损伤模式。通过冲击后压缩试验分析了不同试样的损伤容限。结果发现更高膨胀倍率的泡沫芯子,产生更低的膨胀力,泡沫夹芯板的抗冲击强度降低,但结构具有更优异的吸能效果。高能量和低强度的泡沫芯子都会导致蒙皮更高的损伤程度。试样在10 J能量冲击后的压缩强度衰减率为8.2%,而42 J能量冲击后的压缩强度衰减率达到38.2%。成型压力和芯子的厚度对泡沫夹芯板的损伤容限影响很小。研究确定了热膨胀工艺成型泡沫夹芯复合材料具有高的结构和抗冲击性能可设计性。

Thermal expansion molding process is expected to be integrated to form various foam sandwich composites.The expandable epoxy foam prepreg with an initial thickness of 1 mm was selected,and four kinds of foam sandwich panels with different thicknesses were prepared by controlling the mold cavity size and different molding pressures.The impact energies of 10 J and 42 J were used to study the effects of thermal expansion process and core thickness on the low-velocity impact properties of foam sandwich composites.The damage patterns of different specimens were investigated by ABAQUS finite element analysis,ultrasonic C-scan and the test data.Compression after impact tests were conducted to investigate the damage tolerance of different specimens.The results show that the foam core with higher expansion rate produces lower expansion force,and the impact strength of the foam sandwich board is reduced,but the structure has better energy absorption effect.Both high impact energy and low strength foam cores lead to higher damage degree of the skin.The compression strength decay rate of the sample at10 J impact energy is 8.2%,and the compression strength decay rate of the sample at 42 J impact energy is 38.2%.The forming pressure and the thickness of the core have little effect on the damage tolerance of the foam sandwich plate.The high designability of structural and impact resistance properties of foam sandwich composites formed by thermal expansion process was determined.