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Fabrication, Mechanical Characterization, and Modeling of 3D Architected Materials upon Static and Dynamic Loading


Portela G., Carlos Mauricio (2019) Fabrication, Mechanical Characterization, and Modeling of 3D Architected Materials upon Static and Dynamic Loading. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/75S6-SB32.


Architected materials have been ubiquitous in nature, enabling unique properties that are unachievable by monolithic, homogeneous materials. Inspired by natural processes, man-made three-dimensional (3D) architected materials have been reported to enable novel mechanical properties such as high stiffness- and strength-to-density ratios, extreme resilience, or high energy absorption. Furthermore, advanced fabrication techniques have enabled architected materials with feature sizes at the nanometer-scale, which exploit material size effects to approach theoretical bounds. However, most architected materials have relied on symmetry, periodicity, and lack of defects to achieve the desired mechanical response, resulting in sub-optimal mechanical response under the presence of inevitable defects. Additionally, most of these nano- and micro-architected materials have only been studied in the static regime, leaving the dynamic parameter space unexplored.

In this work, we address these issues by: (i) proposing numerical and theoretical tools that predict the behavior of architected materials with non-ideal geometries, (ii) presenting a pathway for scalable fabrication of tunable nano-architected materials, and (iii) exploring the response of nano- and micro-architected materials under three types of dynamic loading. We first explore lattice architectures with features at the micro- and millimeter scales and provide an extension to the classical stiffness scaling laws, enabled by reduced-order numerical models and experiments at both scales. After discussing the effect of nodes (i.e., junctions) on the mechanical response of lattice architectures, we propose alternative node-less geometries that eliminate the stress concentrations associated with nodes to provide extreme resilience. Using natural processes such as spinodal decomposition, we present pathways to fabricate a version of these materials with samples sizes on the order of cubic centimeters while achieving feature sizes on the order of tens of nanometers. In the dynamic regime, we design, fabricate, and test micro-architected materials with tunable vibrational band gaps through the use of architectural reconfiguration and local resonance. Lastly, we present methods to fabricate carbon-based materials at the nano- and centimeter scales and test them under supersonic impact and blast conditions, respectively. Our work provides explorations into pathways that could enable the use of nano- and micro-architected materials for applications that go beyond small-volume, quasi-static mechanical regimes.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Architected materials; nanomechanics; scaling laws; nanolattices; self-assembly; elastic wave propagation; phononic band gaps; architected composites; supersonic impact
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Mechanical Engineering
Awards:Centennial Prize for the Best Thesis in Mechanical and Civil Engineering, 2019.
Thesis Availability:Withheld
Research Advisor(s):
  • Greer, Julia R. (advisor)
  • Kochmann, Dennis M. (co-advisor)
Thesis Committee:
  • Ravichandran, Guruswami (chair)
  • Daraio, Chiara
  • Greer, Julia R.
  • Kochmann, Dennis M.
Defense Date:16 May 2019
Non-Caltech Author (AT)
Funding AgencyGrant Number
Office of Naval Research (ONR)N00014-16-1-2431
Record Number:CaltechTHESIS:06052019-161606954
Persistent URL:
Related URLs:
URLURL TypeDescription adapted for Chapter 2. adapted for Chapter 3. adapted for Chapter 4. related to Chapter 1. related to Chapter 7. related to Chapter 3.
Portela G., Carlos Mauricio0000-0002-2649-4235
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:11690
Deposited By: Carlos Portela Galindo
Deposited On:07 Jun 2019 01:39
Last Modified:17 Jun 2019 23:04

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