Session: 04-24-01: Advancing Composite Materials through Integrated Multiscale Modeling and Experimental Techniques

Paper Number: 150788

150788 - Energy Absorption and Compressive Mechanical Response of Nanoarchitected Composites at High Strain-Rates 

Nanoarchitected materials with extremely low densities can possess high stiffness, strength, supersonic impact resilience and inelastic energy absorption comparable to that of Kevlar composites (200-400 m/s particle velocity) [1, 2]. Modern transportation, infrastructure, personnel protection, and other instances where resilience against dynamic impact is critical drive the demand for lightweight engineering structural materials with superior energy dissipation capabilities. To create such lightweight, energy-absorbent composites, we developed a 3D laser interference lithography process (LIL) with a metasurface mask that is capable of producing nano-architected sheets, or nanolattices (35μm-thick,2.5 x 2.5cm² wide, 500nm resolution, i.e. internal feature size) made of negative tone epoxy-based photosensitive resist (SU-8) [3]. These sheets are then cleaved into 4x4mm tiles and impregnated into an acetone-diluted epoxy matrix to create 4x4x4mm composite samples with a volume fraction of nanoarchitected layers varying between ~5% and 22%. Two different configurations of nanoarchitected composites were fabricated and tested: (1) interpenetrated (epoxy interdigitated into nanolattice) and (2) layered (discrete layers of dense epoxy and porous nanolattices). We conducted indentation experiments on all samples with a 1mm-diameter flat punch at a quasi-static strain rate of 10^-3s^-1, which reveal that the interpenetrated nanocomposite samples exhibit 68% more energy absorption and undergo 51% more unrecovered deformation than the neat constituent epoxy. In contrast, layered composites performed similarly to a volumetric rule of mixtures combination of constituent materials. In-situ compression experiments on a Split-Hopkinson Pressure Bar (SHPB) at the strain rates of ~4x10³ s^-1 revealed that the interpenetrated composites had the energy absorption capacity ~46% higher than that of the neat epoxy while layered composites exhibited consistent early catastrophic failure with up to 66% lower energy absorption capacity. The stress-strain data, combined with in-situ deformation images convey that the interpenetrated composite configurations underwent a transition in deformation mode – from polymer yielding to microcracking and a concomitant rise in energy absorption capacity up to 86% higher than that of layered nanocomposites configurations, and up to 13.9% higher than that of carbon-based composites reported in literature [4-11]. These improvements in energy absorption are achieved through the addition of regions with high densities of architected material interfaces. We present tortuous (local) failure under the influence of defects as a phenomenological model that can explain enhanced load tolerance enabled by the addition of nano-architected layers, which distribute damage and suppress crack propagation. We compare these results with those of similar materials tested under compression in SHPB showing interpenetrated nanoarchitected composites are capable of energy absorption capacities higher than reported CNT/epoxy or graphene oxide/epoxy composites without benefiting from the material strength and stiffness imparted by the carbon fillers.

 

References

 

1.         Lucas R. Meza, S.D., Julia R. Greer, Strong, lightweight, and recoverable three-dimensional ceramic nanolattices. Science, 2014.

2.         Carlos M. Portela, B.W.E., David Veysset, Yuchen Sun, Keith A. Nelson, Dennis M. Kochmann and Julia R. Greer, Supersonic impact resilience of nanoarchitected carbon. Nature Materials, 2021.

3.         Matias Kagias, S.L., Andrew C. Friedman, Tianzhe Zheng, David Veysset, Andrei Faraon, Julia R. Greer, Metasurface-enabled Holographic Lithography for Impact-absorbing Nano-architected Sheets. Advanced Materials, 2023.

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5.         Ankur Chaurasia , R.S.M.A.P., Polymer-based nanocomposites for impact loading: A review. Mechanics of Advanced Materials and Structures, 2021.

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resin. Journal of Composite Materials 2014.

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8.         Suneev Anil Bansal, A.P.S., and Suresh Kumar, High Strain Rate Behavior of Epoxy Graphene Oxide Nanocomposites. International Journal of Applied Mechanics, 2018. 10(7).

9.         T. Gómez-del Río, J.R., R.A. Pearson, Compressive properties of nano-particle modified epoxy resin at different strain rates. Composites: Part B, 2013.

10.       Veera M. Boddu, M.W.B., Jignesh S. Patel, Ashok Kumar, P. Raju Mantena, Tezeswi Tadepalli, Brahmananda Pramanik, Energy dissipation and high-strain rate dynamic response of E-glass fiber composites with anchored carbon nanotubes. Composites Part B, 2016. 88: p. 44-54.

11.       Ying-Gang Miao, H.-Y.L., Tao Suo, Yiu-Wing Mai, Fa-Qin Xie, Yu-Long Li, Effects of strain rate on mechanical properties of nanosilica/epoxy. Composites Part B, 2016. 96: p. 119-124.

Presenting Author: Kevin Nakahara California Institute of Technology

Presenting Author Biography: I am currently attending Caltech to pursue a PhD in Mechanical Engineering, concentrating in mechanical design, architected materials, composites, and nanomechanics. At heart, I love solving hard problems and that has led me to gain strong experience working in both fundamental and product driven investigations.

Authors:

Kevin Nakahara California Institute of Technology
Barry Lawlor California Institute of Technology
Matias Kagias Lund Univeristy
Julia Greer California Institute of Technology