具有Kevlar短纤维界面增韧的碳纤维/铝蜂窝夹芯板冲击后压缩性能

Compression after impact properties of carbon-fiber/aluminum-honeycomb sandwich panels with short-Kevlar-fiber toughening

碳纤维夹芯板受到冲击载荷后易发生分层损伤,在工程应用中严重影响结构安全。首先对碳纤维/铝蜂窝夹芯板界面进行Kevlar短纤维增韧设计;其次对比研究了Kevlar短纤维界面增韧及未增韧夹芯板的低速冲击行为和冲击后压缩行为,将其冲击后剩余压缩强度、能量吸收及破坏模式进行对比;最后运用数字图像相关技术(DIC)获取增韧及未增韧试件在冲击后压缩过程中的应变云图。结果表明:低速冲击过程中,Kevlar短纤维增韧可以有效提高碳纤维/铝蜂窝夹芯板的冲击损伤阻抗,增韧试件的临界损伤阈值载荷明显高于未增韧试件;相比于未增韧试件,4种冲击能量下增韧试件的冲击后剩余压缩强度(CAI)值分别提高了2.68%、9.24%、4.65%、11.13%,能量吸收分别提高了69.09%、52.88%、55.03%、101.70%;对碳纤维/铝蜂窝夹芯板冲击后压缩过程中的DIC观测,进一步验证了芳纶短纤维对界面的增韧效果,并揭示了增韧界面对结构的增强机制。

Delamination between face sheets and core is one of the most common damage mode of carbon-fiber sandwich panels under impact loading,which seriously affects structural safety.Firstly,short-Kevlar-fibers were used for toughening the interface of carbon-fiber/aluminum-honeycomb sandwich panel.Secondly,low velocity impact and compression after impact tests were conducted for plain and toughened specimens.The residual compression strength,energy absorption and failure mode were compared.Finally,the strains of plain and toughened specimens during compression after impact test were obtained by digital image correlation(DIC).The results show that short-Kevlar-fiber toughening is capable to effectively increase the impact damage resistance of carbonfiber/aluminum-honeycomb sandwich panel,and the damage threshold load of toughened specimens is significantly higher than that of plain specimens.Compared with the plain specimens,the residual compression strength values after impact of toughened specimens are increased by 2.68%,9.24%,4.65%and 11.13%,respectively,under four different impact energies.Meanwhile the energy absorption values of toughened specimens are increased by 69.09%,52.88%,55.03%and 101.70%,respectively.Furthermore,DIC observations were used to investigate the toughening effects of short-Kevlar-fibers and the strengthening mechanism.