To investigate the ballistic performance and damage characteristics of quasi threedimensional（3D） needle-punched Cf/SiC composites prepared by chemical vapor infiltration（CVI）,penetration experiments were conducte...To investigate the ballistic performance and damage characteristics of quasi threedimensional（3D） needle-punched Cf/SiC composites prepared by chemical vapor infiltration（CVI）,penetration experiments were conducted by using 7.62 mm armor piercing incendiary（API）.Macro and micro fracture morphologies were then observed on recycled targets.The results show that the protection coefficient of 3D Cf/SiC composites is 2.54.High porosity and many micro thermal stress cracks may directly lead to the lower ballistic performance.Flat fracture morphology was observed on the crater surface.The low dynamic fracture strength along layer direction may be attributed to the voids and microcracks caused by residual thermal stress.The damage characteristics of Cf/Si C composites include matrix cracking,fiber bundle cracking,interfacial debonding,fiber fracture,and fiber bundle pull-out.And interfacial debonding and fiber fracture may play major roles in energy absorption.展开更多
The use of carbon nanotubes in composite hard armor is discussed in this study.The processing techniques to make various armor composite panels consisting of Kevlar■29 woven fabric in an epoxy matrix and the subseque...The use of carbon nanotubes in composite hard armor is discussed in this study.The processing techniques to make various armor composite panels consisting of Kevlar■29 woven fabric in an epoxy matrix and the subsequent V50 test results for both 44 caliber soft-point rounds and 30 caliber FSP(fragment simulated projectile)threats are presented.A 6.5%improvement in the V50 test results was found for a combination of 1.65 wt%loading of carbon nanotubes and 1.65 wt%loading of milled fibers.The failure mechanism of carbon nanotubes during the ballistic event is discussed through scanning electron microscope images of the panels after the failure.Raman Spectroscopy was also utilized to evaluate the residual strain in the Kevlar■29 fibers post shoot.The Raman Spectroscopy shows a Raman shift of 25 cm^(−1) for the Kevlar■29 fiber utilized in the composite panel that had an enhancement in the V50 performance by using milled fiber and multi-walled carbon nanotubes.Evaluating both scenarios where an improvement was made and other panels without any improvement allows for understanding of how loading levels and synergistic effects between carbon nanotubes and milled fibers can further enhance ballistic performance.展开更多
基金Funded by the National Natural Science Foundation of China(No.51271036)
文摘To investigate the ballistic performance and damage characteristics of quasi threedimensional（3D） needle-punched Cf/SiC composites prepared by chemical vapor infiltration（CVI）,penetration experiments were conducted by using 7.62 mm armor piercing incendiary（API）.Macro and micro fracture morphologies were then observed on recycled targets.The results show that the protection coefficient of 3D Cf/SiC composites is 2.54.High porosity and many micro thermal stress cracks may directly lead to the lower ballistic performance.Flat fracture morphology was observed on the crater surface.The low dynamic fracture strength along layer direction may be attributed to the voids and microcracks caused by residual thermal stress.The damage characteristics of Cf/Si C composites include matrix cracking,fiber bundle cracking,interfacial debonding,fiber fracture,and fiber bundle pull-out.And interfacial debonding and fiber fracture may play major roles in energy absorption.
基金supported by Florida Space Grant Consortium(FSGC)under grant number NASA NNX10AM01H.
文摘The use of carbon nanotubes in composite hard armor is discussed in this study.The processing techniques to make various armor composite panels consisting of Kevlar■29 woven fabric in an epoxy matrix and the subsequent V50 test results for both 44 caliber soft-point rounds and 30 caliber FSP(fragment simulated projectile)threats are presented.A 6.5%improvement in the V50 test results was found for a combination of 1.65 wt%loading of carbon nanotubes and 1.65 wt%loading of milled fibers.The failure mechanism of carbon nanotubes during the ballistic event is discussed through scanning electron microscope images of the panels after the failure.Raman Spectroscopy was also utilized to evaluate the residual strain in the Kevlar■29 fibers post shoot.The Raman Spectroscopy shows a Raman shift of 25 cm^(−1) for the Kevlar■29 fiber utilized in the composite panel that had an enhancement in the V50 performance by using milled fiber and multi-walled carbon nanotubes.Evaluating both scenarios where an improvement was made and other panels without any improvement allows for understanding of how loading levels and synergistic effects between carbon nanotubes and milled fibers can further enhance ballistic performance.
