Rod Lakes

Rod Lakes
Wisconsin Distinguished Professor
Department of Engineering Physics and Department of Materials Science
541 Engineering Research Building
Mechanics of Materials Group For Rod Lakes' main web page press go

Statement on Research by Roderic Lakes, professor of engineering

1 Overview
    We have pioneered the conceptualization, synthesis of a variety of novel materials with extreme and unusual / anomalous properties.
    In our laboratory we have developed the first negative Poisson's ratio 3D materials (Science 1987). This gave rise to considerable publicity including coverage in the New York Times, the Chicago Tribune and many others. Research by others in this area following this article continues to the present time. International conferences are held on the topic, now called auxetic materials.
    We have developed the first materials with extreme thermal expansion tunable from large positive, through zero, to large negative. This has stimulated much research by others including several multi university DARPA projects.
    We are also the first to use the concept of negative stiffness to attain arbitrarily large material damping and stiffness in designed composites with phase transforming inclusions or lumped elements (Nature 2001, Science 2007, Phys. Rev. Lett. 2001). Materials can be much stiffer than diamond over a range of temperature. This has stimulated much research by others including several multi university DARPA projects.
    We designed and created materials with structural hierarchy (Nature 1993} that exhibit extremely high ratios of compressive strength to weight. This has stimulated much research by others particularly since the advent of 3D printing.
    We designed and created viscoelastic materials that greatly exceeded the performance of the best polymer damping layers.
In the laboratory we can characterize viscoelastic response of composites over eleven decades (a factor 10^11) in frequency and time with no appeal to time temperature superposition.
    We conceptualized and created the first chiral elastic materials. These and related materials are nonclassical. They exhibit behavior such as squeeze twist coupling which cannot occur in a classically elastic solid.

2 Experimental aspects
    Research activity is interdisciplinary in nature and includes the following areas. Holographic and optical methods; viscoelasticity; characterization of materials such as fibrous composites, cellular solids, biomaterials, dissipative piezoelectric solids, and human tissue including bone, tendon, and ligament; evaluation of structure-property relationships in various materials; experimental mechanics as a tool for materials characterization; methods include ultrasonics, resonant ultrasound spectroscopy, holographic interferometry, and viscoelastic spectroscopy; development of materials with novel microstructures and novel properties; holographic optical elements.

3 Unifying theme
    The theme which links the areas of research is the quest for understanding the link between structure and physical properties of materials. Novel experimental methods, when appropriate, are used for the characterization of materials. With sufficient understanding of structure-property relations is has been possible to create new classes of materials with extreme or unusual physical properties. Both composite theory and materials science are involved in the process.