Polymer nanocomposites are seeing more frequent use in armor applications. The role of the microstructure on the performance of these materials under dynamic tensile loading is of particular interest. In the present study, plate impact experiments were conducted in order to observe the dynamic response of a neat epoxy (EPON 828) and an epoxy/carbon nanotube composite. The objective was to examine the effect of nano-scale particle inclusions on the spall strength of the composite. The material response was resolved with the combined use of shock pins and a multi-channel photonic Doppler velocimeter. The addition of raw carbon nanotubes (CNT) to epoxy resulted in a composite material with lower spall strengths compared to strengths measured for neat epoxy at elevated shock stresses. Tensile strain rate was found to have the greatest effect on spall strength. Recovered composite fragments were imaged with a scanning electron microscope. Instances of nanotube pull-out were identified on internal fracture surfaces. The low spall strengths of the epoxy/CNT composite were attributed to an increase in the density of potential nucleation sites for spallation caused by presence of the nanotubes in the matrix.

20th Biennial American Physical Society Conference on Shock Compression of Condensed Matter, SCCM 2017
Department of Mechanical and Aerospace Engineering

Pepper, J.E. (Jonathan E.), Huneault, J. (Justin), Rahmat, M. (Meysam), & Petel, O. (2018). Spall strength measurements in EPON 828 epoxy and an epoxy/carbon nanotube composite. In AIP Conference Proceedings. doi:10.1063/1.5044833