Caleb Widstrand Earns Best Master’s Thesis

Caleb Widstrand completed and defended his Master’s of Science thesis, “Wave Propagation in Periodic, Configurable Kerfed Metamaterials,” in 2021 under the direction of his advisor Professor Stefano Gonella. And now, Widstrand’s thesis has been chosen as the best Master’s Thesis within the Department of Civil, Environmental, and Geo- Engineering (CEGE).

The Department of Civil, Environmental, and Geo- Engineering produces a broad range of cutting-edge research that addresses critical challenges in designing and protecting our infrastructure, environment, and water resources. One of the key areas of research centers around the engineering and design of resilient structures using next-generation materials with new physiochemical properties that make them more adaptive and resistant to environmental hazards.

Widstrand’s topic, “Wave Propagation in Periodic, Configurable Kerfed Metamaterials,” is interdisciplinary and blends the fields of innovative new materials with architecture and design. The CEGE graduate committee deemed Widstrand’s highly innovative work to be a great example of how civil engineering research in CEGE is addressing current and future needs of society.

Widstrand explored the dynamical functionalities of kerfed metamaterials. Kerfing is a perforation process (sometimes performed via laser) that introduces an intricate pattern of cuts in thin materials so that the elastic deformation properties of the material change when subjected to an applied force. Kerfing can be performed on a variety of materials, from composites, such as medium-density fiberboard, to metals, like aluminum or steel. Large kerfed panels are are used in architectural applications to create free-form structures for building facades. Kerfed panels can also address functional requirements, for example, mitigating the impact of severe weather.

Widstrand combined numerical simulations and laboratory experiments to evaluate the methodological challenges of producing kerfed materials and the dynamic structural properties gained by kerfing materials. In his thesis, Widstrand demonstrated that kerfed materials only propagate waves and vibrations of specific frequencies. Thus, kerfed materials can be designed to withstand a defined range of dynamical loads. Widstrand demonstrated how new construction methods and materials can integrate aesthetic architectural design with structural aspects of improved resistance to dynamic loadings, for example, allowing structures to withstand forces exerted by severe rain or wind conditions.

His work led to publication in Extreme Mechanics Letters (doi: 10.1016/j.eml.2022.101693), “Bandgap tuning in kerfed metastrips under extreme deformation,” by Caleb Widstrand, Negar Kalantar, and Stefano Gonella.

Widstrand’s thesis will be forwarded to the college where it will compete against other theses progressing to the University for the Midwestern Association of Graduate Schools (MAGS) Distinguished Master of Science Thesis Award. Widstrand is now working on his Ph.D. with Stefano Gonella, so we can expect to see more good work on this topic soon.