Jordan R. Raney

Postdoctoral Fellow

John A. Paulson School of Engineering & Applied Sciences

Wyss Institute for Biologically Inspired Engineering

Harvard University

Mechanics by design: 3D printing architected engineering materials and expanding design space

The internal structural features of material systems used in engineering applications greatly affect their macroscopic mechanical properties. For example, natural structural materials such as wood possess highly heterogeneous mesoscale architectures, with hierarchical structure, spatially-varying fiber alignment, non-uniform density, and graded porosity. These features are the result of localized structural and compositional optimization, producing maximal bulk mechanical properties that greatly exceed those of the constituent materials. In contrast, due to the limitations of current manufacturing processes, synthetic engineering materials typically lack optimized, carefully-defined mesoscale features. As a result, they lack the level of performance (as defined by metrics such as strength, toughness, mass efficiency, etc.) that is ultimately possible. Additive manufacturing techniques have begun to enable more nuanced control of the internal structure of engineering materials, but many challenges remain. Perhaps most significantly this includes notable process-intrinsic limits to the palette of printable materials. Here, direct write 3D printing is applied to the construction of architected engineering materials with the goal of enabling a new degree of control over mechanical properties in high-quality materials relevant to engineering applications. Two example systems will be discussed: (i) beam-based soft architectures that make use of bistability to controllably store and release elastic strain energy; and (ii) bioinspired fiber composites with fiber alignment that can be locally, heterogeneously assigned to achieve excellent mass efficiency and control of strain and failure localization.

Biography:

Jordan R. Raney is a Postdoctoral Fellow in the John A. Paulson School of Engineering and Applied Sciences and the Wyss Institute for Biologically Inspired Engineering at Harvard University. His research focuses on the mechanics and fabrication of novel material architectures, including hierarchical, heterogeneous, fibrous, and soft systems. He received his Ph.D. in materials science at the California Institute of Technology, where he was the recipient of a National Defense Science & Engineering Graduate Fellowship and the Demetriades-Tsafka-Kokkalis Prize in Nanotechnology for his dissertation.