Tyler Engstrom

PhD, Penn State, 2015.
Area of Study: Physics

BS, South Dakota School of Mines and Technology, 2005.
Area of Study: Metallurgical Engineering

Assistant Professor, University of Northern Colorado
Department of Physics and Astronomy (2021-Present)

Product Development Scientist, MiTeGen
(2020-2021)

Visiting Assistant Professor, Hobart and William Smith Colleges
(2019 & 2016)

Postdoctoral Researcher, Syracuse University
(2016-2018)

Areas of Interest

I am a soft matter and biological physicist with professional experiences spanning theoretical, computational, and experimental projects in both industry and academia. A major theme of my recent work is mechanical instabilities in soft and/or slender structures. These structures might be made of living tissues. For example, the folds of your brain and the crypts and villi in your intestines were created when two adjacent tissue layers grew at different rates, setting up a wrinkling instability. The foveal pit in the macula region of your eye – my current fascination – appears to form by a related mechanism. In studying these biomechanical phenomena, I collaborate with (and learn a lot from) biologists at UNC and elsewhere. For another example of this work, consider thin elastic filaments like carbon nanotubes or the microtubules in your cells, that can vibrate and twist and buckle. The mathematics describing all this is remarkably like the mathematics of quantum mechanics in one dimension, and so I am interested in trying to learn new things about classical elastic systems from analogous quantum mechanical systems, and vice versa. In addition to mechanical instabilities, I also have a general interest in cell, tissue, and solid mechanics. 

Building and testing new models of eye morphogenesis

This project is an interdisciplinary, experimental/theoretical/computational study of choroid fissure closure and foveal pit formation in the developing vertebrate eye, encompassing 3 subprojects. Supported by Engstrom and James’ NIH grant that runs from Aug 2024 – July 2027. Roughly a dozen UNC undergrads will be involved over this period.

Predicting crease patterns by analogy with line charge crystallization

This project investigates patterns formed by surface creases in compressed hyperelastic materials. We are using Engstrom & Schwarz’s prior creasing model in combination with a basin-hopping algorithm to look for ground state crease patterns. Several UNC undergraduates are involved.

Prestress-generated odd elasticity

Using results from 20th Century elasticity theory, we obtain a recipe for dynamically stable, prestress-induced odd elasticity. The recipe is then used to derive a minimal lattice model – a 2D triangular lattice with a mixture of positive and negative stiffness bonds under biaxial prestress – that functions as an odd elastic waveguide. Behavior of this waveguide is explored through numerical simulations.

Shear jamming of popcorn

In biological contexts, proliferation can drive a system from a solid to a fluid, or in other words, unjams the system. Here we will investigate the jamming transition in the context of a nonliving granular system that also features proliferation: popping popcorn and other cereals. This will involve experiments with a custom built annular shear cell that sits on top of a heated surface.

Soft Matter Physics

I am a soft matter and biological physicist with professional experiences spanning theoretical, computational, and experimental projects in both industry and academia. One of my current projects is an NIH-funded collaboration between my lab and that of Andrea James (UNC Bio); we are developing and testing several new models of eye morphogenesis with the goal of better understanding certain developmental diseases of the eye. Another current project, funded by RCSA, has to do with a new branch of continuum elasticity theory known as “odd elasticity.” Specifically, my work focuses on the connection between prestress-generated and activity-generated odd elasticity, and the application of the former to waveguides. In addition to these projects, I also have a general interest in cell, tissue, and solid mechanics.

• Demands on early-career faculty, T. A. Engstrom, Phys. Today 78, 9 (2025)
• Dynamics of certain Euler-Bernoulli rods and rings from a minimal coupling quantum isomorphism, T. A. Engstrom, Phys. Rev. E 107, 065005 (2023)
• High-resolution single-particle cryo-EM of samples vitrified in boiling nitrogen, T. A. Engstrom, J. A. Clinger, K. A. Spoth, O. B. Clarke, D. S. Closs, R. Jayne, B. A. Apker, and R. E. Thorne, IUCrJ 8, 1-11 (2021)
• The quantum character of buckling instabilities in thin rods, T. A. Engstrom, Am. J. Phys. 88, 845 (2020)
• Loops versus lines and the compression stiffening of cells, M. C. Gandikota, K. Pogoda, A. van Oosten, T. A. Engstrom, A. E. Patteson, P. A. Janmey, & J. M. Schwarz, Soft Matter 16, 4389 (2020)
• Compression stiffening in biological tissues: On the possibility of classic elasticity origins, T. A. Engstrom, K. Pogoda, K. Cruz, P. A. Janmey, & J. M. Schwarz, Phys. Rev. E 99, 052413 (2019)
• Cerebellar folding is initiated by mechanical constraints on a fluid-like layer without a cellular pre-pattern, A. K. Lawton, T. A. Engstrom, D. Rohrbach, M. Omura, D. H. Turnbull, J. Mamou, Teng Zhang, J. M. Schwarz, & A. L. Joyner, eLife 8, e45019 (2019)
• Buckling without bending: a new paradigm in morphogenesis, T. A. Engstrom, Teng Zhang, A. K. Lawton, A. L. Joyner, & J. M. Schwarz, Phys. Rev. X 8, 041053 (2018)
• Surface creasing of soft elastic continua as a Kosterlitz-Thouless transition, T. A. Engstrom & J. M. Schwarz, Europhys. Lett. 118, 56005 (2017)
• Crystal chemistry of three-component white dwarfs and neutron star crusts: phase stability, phase stratification and physical properties, T. A. Engstrom, N. C. Yoder, & V. H. Crespi, Astrophys. J. 818:183 (2016)
• Microphysics of neutron star outer envelopes in the periodized, magnetic Thomas-Fermi model, T. A. Engstrom, V. H. Crespi, B. J. Owen, J. Brannick, & Xiaozhe Hu, arXiv:1409.3299 (2015)
• A computer-controlled classroom model of an atomic force microscope, T. A. Engstrom, M. M. Johnson, P. C. Eklund, & T. J. Russin, Phys. Teach. 53 (2015)
• Probing phase coherence in solid helium using torsional oscillators of different path lengths, D. Y. Kim, J. T. West, T. A. Engstrom, N. Mulders, & M. H. W. Chan, Phys. Rev. B 85, 024533 (2012)
• Effects of friction stir welding on mechanical properties of the cast aluminum alloys A319 and A356, M. L. Santella, T. A. Engstrom, D. Storjohann, & T.-Y. Pan, Scr. Mater. 53, 2 (2005)