Woodruff School of Mechanical Engineering

Faculty Candidate Seminar


Architected elastic meta-structures for low frequency and broadband energy absorption


Dr. Kathryn Matlack


Department of Mechanical and Process Engineering, ETH Zurich


Thursday, March 3, 2016 at 11:00:00 AM


MRDC Building, Room 4211


Dr. Michael Leamy


Architected materials have the ability to manipulate and control stress wave propagation, which is essential for enhanced vibration mitigation, sound attenuation, and impact absorption properties. Recent research has relied on two mechanisms for engineering band gaps to forbid certain frequencies from propagating through a material: (1) phononic crystals rely on their structural periodicity to form Bragg band gaps at wavelengths on the order of their unit cell size; (2) acoustic metamaterials exploit local resonances to form narrow band gaps at low frequencies. However, existing materials find limited use in engineering applications because they cannot achieve both broadband and low frequency control of elastic or acoustic waves without requiring impractical sizes and masses. Here, I introduce a new class of materials, labeled elastic meta-structures, that supports the formation of wide band gaps at low frequencies, by exploiting resonating elements to broaden and lower Bragg gaps, while simultaneously reducing the mass of the system. We use analytical and finite element modeling to simulate wave propagation through these structures and inform the designs. We demonstrate these principles experimentally using novel 3D printing methods to fabricate functional composite meta-structures on multiple length scales. This research informs the design of tailored materials that can effectively control elastic wave propagation, resulting in increased efficiency of critical components in energy infrastructure, robust and lightweight sound absorbers for buildings, and protection of MEMS devices from harmful impacts.


Dr. Kathryn Matlack is a postdoctoral researcher at ETH Zurich in the Department of Mechanical and Process Engineering. She was awarded the ETH Postdoctoral Fellowship for her research on elastic metamaterials for vibration absorption and wave guiding applications. She received her B.S. in mechanical engineering from MIT, and her Ph.D. in mechanical engineering from the Georgia Institute of Technology where she was an NSF Graduate Research Fellow. She was awarded the Sigma Xi Best Ph.D. Thesis for her research on developing a nonlinear ultrasonic technique to monitor radiation damage in nuclear reactor structural material.


Refreshments will be served.