Research

3D Printed Architected Metamaterials

Architected metamaterials can manipulate and control stress wave propagation through spatial variations of the geometry and composition.  Such design strategies lead to tailored materials and structures that are multifunctional and can satisfy conflicting design requirements, such as high stiffness and strength properties while also mitigating vibrations, attenuating sound, and absorbing impacts. Why does this matter? One of the “grand challenges” for material and structure design is to satisfy multiple and oftentimes conflicting design requirements. Energy infrastructure, especially in remote and extreme environments e.g. offshore wind turbines and advanced nuclear ...
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Design of Metamaterials: Topologically Insulating Mechanical Metamaterials

Topological insulators are a unique class of electronic materials that exhibit protected edge states that are insulating in the bulk, and immune to back-scattering and defects. Discrete models, such as mass-spring systems, provide a means to translate these properties, based on the quantum hall spin effect, to the mechanical domain. We are developing methods to engineer mechanical metamaterials that support topologically-protected and defect-immune edge states (vibrational modes), directly from the mass-spring model of a topological insulator. These metamaterials have potential applications as programmable waveguides, damage-tolerant materials, and elastic ...
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Nonlinear Ultrasound for Radiation Damage Detection

Nuclear generation currently accounts for roughly 20% of the US baseload power generation.  Yet, many US nuclear plants are entering their first period of life extension and older plants are currently undergoing assessment of technical basis to operate beyond 60 years. Critical structural components, such as the reactor pressure vessel (RPV), will be exposed to higher levels of neutron radiation than they were originally intended to withstand. Why does this matter? Neutron radiation in these types of steel components causes a cascade ...
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