Lecture of L. Valdevit : Hierarchical architected materials as a platform for novel multifunctional systems

L. Valdevit, Mechanical and Aerospace Engineering Department
University of California, Irvine CA 92697

Abstract
Periodic cellular materials are desirable for applications requiring high specific stiffness and strength. If the architecture is open-celled, a number of multifunctional attributes can be added, with potential for multi-objective optimization. Although conventional industrial technologies limit the achievable unit cell complexity, recent progress in
advanced manufacturing is enabling fabrication of hierarchical cellular materials of nearly any topology with wide dimensional bandwidth (i.e., the ratio of the dimension of the largest to the smallest feature in the architecture).
Hierarchical unit cell designs with wide dimensional bandwidth are showing particular promise, often revealing unique mechanical behavior. Furthermore, if the smallest feature in the architecture is at the sub-micron scale, unique size effects in plasticity can further
improve the mechanical response.
In this presentation, I will discuss novel ultra-light micro-architected nickel hollow-truss lattices with unprecedented combinations of density, stiffness, strength and damping characteristics. Results of extensive experimental investigations (both at the nano and macro-scale) will be presented, alongside numerical models and optimal design tools.
Some preliminary work on ceramic and hybrid architected materials manufactured by 3D printing will also be discussed. Collectively, all these investigations indicate that a strong synergism among advanced manufacturing, materials science, multi-scale experimental
and computational mechanics and sophisticated optimization tools is required to reach the full potential of hierarchical architected materials.