Z-pin增强泡沫夹层结构面压缩性能研究

Through-Thickness Compression Properties of Z-Pin Reinforced Foam Core Sandwich

Z-pin增强泡沫夹层结构作为一种新兴的复合材料夹层结构形式,能够克服传统蜂窝夹层结构的诸多缺陷。采用预浸碳纤维增强Rohacell夹芯,进行Z-pin角度为15°和25°,夹芯厚度分别为12.7mm和8mm两种Z-pin增强泡沫夹层结构的面内压缩性能试验,并与相同批次和尺寸的未增强件进行对比,考察其对传统泡沫夹层结构的增强作用。试验发现X状Z-pin增强能够大幅度提高夹层结构的压缩强度与刚度。同时,增强材料表现出与传统泡沫夹层结构不同的压缩变形与破坏模式。证实Z-pin的弹性屈曲控制着结构的压缩强度,夹芯厚度和Z-pin角度影响Z-pin屈曲的计算长度,从而成为材料压缩强度的控制因数。在此基础上,考虑面板对Z-pin的有限转动约束,通过引进约束修正系数改进现有的压缩强度预测模型,预测值与试验结果更加接近。

As a novel sandwich structures, Z-pin reinforced foam core sandwich can overcome the limitations of traditional honeycomb core sandwich. A series experiments were carried out to investigate the responses of Z-pinned foam core sandwich under compressive loading, including inclination angles of 15° and 25°with foam core thickness of 12.7mm and 8mm, and each group of them had a contrasted one. Experimental results showed Z-pinned foam core could reinforce the compression modulus and strength of sandwich markedly, and had a deformation and failure map which was different from unreinforced one under compression. The thickness of foam core and inclination angle of pin were dominated factors of compression strength, by influencing the effective length of Z-pin buckling. Considered the actual restriction of face sheets, the existing compression strength model was ameliorated by employing restriction correction coefficient, made the prediction results approach and agree better with the measured results.