Mechanical and Civil Engineering Seminar

Title: "No Small Measure: Using Nanostructure to Create Materials with Superior Toughness"

Abstract: Nanomaterials leverage size-dependent effects to achieve extraordinary mechanical properties, including high strength, flaw resistance and enhanced ductility. Natural systems like shell and bone have intricate nanoscale architectures that effectively dissipate energy and impede cracks, and while the effect of architecture has long been explored, the role of size on toughness is not well understood. This talk examines how different ordered and stochastic nanoarchitected materials can be used to enhance toughness, and how fracture size-effects can alter the emergent ductility of materials at small length scales. Topics include: 1) polymeric nano-Bouligand architectures with twisted nanofibers that dissipate energy through nanoscale-enhanced ductility, 2) nanocellular polymeric foams that defy traditional toughness scaling laws, 3) shell-inspired spinodal architectures with structural gradients that slow crack growth, 4) layered architectures that exploit size-enhanced ductility for exceptional toughness, and 5) interpenetrating lattices that have toughness 6x higher than their bulk constituents. This work reframes ductility and toughness as architecture- and size-dependent properties, revealing how nanoengineering can break classic trade-offs between strength, density, and toughness.

Bio: Lucas Meza is an Assistant Professor in Mechanical Engineering at the University of Washington. His research investigates new ways of engineering material properties at the micro- and nanoscale. He did his postdoc at the University of Cambridge, where he studied the micromechanical behavior of 3D woven fiber composites. He obtained his PhD in 2016 in mechanical engineering from the California Institute of Technology (Caltech) for his work on ultralight, hierarchical metamaterials composed of nanoscale ceramics. His work is supported in large part by the National Science Foundation.