Nix Award and Lecture Symposium: Nanomechanics and Mechanomaterials: Nix Award III
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS: Nanomechanical Materials Behavior Committee
Program Organizers: Wendelin Wright, Bucknell University; Gang Feng, Villanova University

Wednesday 2:00 PM
March 2, 2022
Room: 259A
Location: Anaheim Convention Center

Session Chair: Gang Feng, Villanova University; Wendelin Wright, Bucknell University; Erica Lilleodden, Helmholtz-Zentrum Geesthacht

2:00 PM  Invited
2022 William D Nix Award Lecture: Mechano-materials: Engineering Mechanical Properties of Materials with Internal Interfaces and Lightweight Structures: Huajian Gao1; 1Nanyang Technological University
    While conventional mechanics of materials offers passive access to mechanical properties of materials in existing forms, a paradigm shift is emerging towards proactive design of material properties/functionalities by leveraging the force-geometry-property relationships. Such an emerging field can be coined as “mechano-materials”. In this talk, we discuss a couple of examples of mechano-materials research. The first example is concerned with a nature-inspired design of fatigue resistant metals with internal interfaces. We report a history-independent and stable cyclic response in bulk copper samples with microstructures mimicking the highly oriented nanoscale twin boundaries in conch shells. We demonstrate that this unusual cyclic behaviour is governed by an unusual type of dislocations called correlated ‘necklace’ dislocations (CNDs). The second example has to do with the design, fabrication and mechanics of 3D nanolattices with octet- and iso-truss topologies, achieving unprecedent mechanical properties such as specific strength, superior fracture strains and insensitivity to fabrication-induced defects.

3:00 PM  Invited
Release with Ease – Bioinspired Designs for Placing Micro-objects: Eduard Arzt1; Xuan Zhang1; Yue Wang1; René Hensel1; 1INM – Leibniz Institute for New Materials and Saarland University
    In small dimensions, objects tend to tenaciously stick to each other. This poses a severe challenge for the handling of micro-components by adhesive polymeric microstructures. Inspired by biological evolution, such surface microstructures have become an innovative and sustainable strategy for robotic gripping and handling. Following successful model experiments, theory and numerical simulation, reliable and robust gripping of objects is now on the path to commercialization. However, as the components to be handled are shrinking in size, their weight will be too small to allow detachment by conventional mechanisms. Our group has proposed various designs that will allow the controlled release and placement of micro-objects. Inspired by a biological example, a metamaterial involving a programmable snap-action was developed. With an unprecedented switching ratio (between high and low adhesion) exceeding 50, such microstructure concepts may enable an energy-efficient solution to handling problems under extreme conditions.

3:30 PM Break Coffee Break

4:00 PM  Invited
Modeling Programmable Drug Delivery in Bioelectronics with Electrochemical Actuation: Yonggang Huang1; 1Northwestern University
    Drug delivery systems featuring electrochemical actuation represent an emerging class of biomedical technology with programmable volume/flowrate capabilities for localized delivery. For programmable delivery, the available flowrate control and delivery time models fail to consider key variables of the drug delivery system––microfluidic resistance and membrane stiffness. Here we establish an analytical model that accounts for the missing variables and provides a scalable understanding of each variable influence in the physics of delivery process (i.e., maximum flowrate, delivery time). This analytical model accounts for the key parameters––initial environmental pressure, initial volume, microfluidic resistance, flexible membrane, current, and temperature––to control the delivery and bypasses numerical simulations allowing faster system optimization for different in vivo experiments. We show that the delivery process is controlled by three nondimensional parameters, and the volume/flowrate results from the proposed analytical model agree with the numerical results and experiments.

4:30 PM  Invited
Materials by Design: Three-dimensional (3D) Nano-architected Meta-materials: Julia Greer1; 1California Institute of Technology
     Creation of simultaneously strong and lightweight materials can be achieved by incorporating architecture into material design. Dominant properties of such meta-materials are driven by multi-scale nature: from characteristic microstructure (atoms) to individual constituents (nanometers) to structural components (microns) to overall macro-architectures. To harness beneficial properties of 3D nano-architected meta-materials, it is critical to assess their properties at each relevant scale while capturing over­all structural complexity. In this Nix III symposium, my talk will focus on design, synthesis, and characterization of nano-architected materials created via additive manufacturing (AM) techniques and on their mechanical response as a function of architecture, constituent materials, and microstructure. These “meta-materials” exhibit superior and tunable properties, i.e. impact resilience, recoverability, failure suppression, anisotropic stiffness at ex­tre­me­ly low densities, and lend themselves to novel functionalities. We strive to uncover synergy between atomic-level microstructure and nano-sized external dimensionality, where competing material- and structure-induced size effects drive overall response.