TY - JOUR
T1 - Carbon-nanofiber-reinforced syntactic foams
T2 - Compressive properties and strain rate sensitivity
AU - Poveda, Ronald L.
AU - Gupta, Nikhil
N1 - Funding Information:
This work is also supported by the Office of Naval Research through Grant N00014-10-1-0988 and National Science Foundation GK-12 Fellows grant 0741714. The authors thank 3M, MN for providing glass microballoons and relevant technical information. The authors thank Dr. Dung D. Luong, Gleb Dorogokupets, Sriniket Achar, and Andres Donoso for help in material fabrication, specimen preparation, and testing. Drs. Deepam Maurya and Shashank Priya are thanked for providing TEM observations.
PY - 2014/1
Y1 - 2014/1
N2 - The current study is focused on exploring the possibility of reinforcing syntactic foams with carbon nanofibers (CNFs). Syntactic foams are hollow, particle-filled composites that are widely used in marine structures and are now finding applications in other modes of transportation due to their high stiffness-to-weight ratio. The compressive properties of syntactic foams reinforced with CNFs are characterized over the strain rate range of 10 -4 to 3, 000 s-1, which covers seven orders of magnitude. The results show that despite lower density with respect to neat epoxy, CNF/syntactic foams can have up to 7.3% and 15.5% higher quasi-static compressive strength and modulus, respectively, for the compositions that were characterized in the current study. In addition, these properties can be tailored over a wide range by means of hollow particle wall thickness and volume fraction, and CNF volume fraction. The compressive strength of CNF/syntactic foams is also shown to generally increase by up to a factor of 3.41 with increasing strain rate when quasi-static and high-strain-rate testing data are compared. Extensive microscopy of the CNF/syntactic foams is conducted to understand the failure and energy absorption mechanisms. Crack bridging by CNFs is observed in the specimens, which can delay final failure and increase the energy absorption capacity of the specimens. Deformation of CNFs is also noticed in the material microstructure. The deformation and failure mechanisms of nanofibers are related to the test strain rate and the structure of CNFs.
AB - The current study is focused on exploring the possibility of reinforcing syntactic foams with carbon nanofibers (CNFs). Syntactic foams are hollow, particle-filled composites that are widely used in marine structures and are now finding applications in other modes of transportation due to their high stiffness-to-weight ratio. The compressive properties of syntactic foams reinforced with CNFs are characterized over the strain rate range of 10 -4 to 3, 000 s-1, which covers seven orders of magnitude. The results show that despite lower density with respect to neat epoxy, CNF/syntactic foams can have up to 7.3% and 15.5% higher quasi-static compressive strength and modulus, respectively, for the compositions that were characterized in the current study. In addition, these properties can be tailored over a wide range by means of hollow particle wall thickness and volume fraction, and CNF volume fraction. The compressive strength of CNF/syntactic foams is also shown to generally increase by up to a factor of 3.41 with increasing strain rate when quasi-static and high-strain-rate testing data are compared. Extensive microscopy of the CNF/syntactic foams is conducted to understand the failure and energy absorption mechanisms. Crack bridging by CNFs is observed in the specimens, which can delay final failure and increase the energy absorption capacity of the specimens. Deformation of CNFs is also noticed in the material microstructure. The deformation and failure mechanisms of nanofibers are related to the test strain rate and the structure of CNFs.
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U2 - 10.1007/s11837-013-0791-0
DO - 10.1007/s11837-013-0791-0
M3 - Article
AN - SCOPUS:84893685754
SN - 1047-4838
VL - 66
SP - 66
EP - 77
JO - JOM
JF - JOM
IS - 1
ER -