Samuel Wallace
Ph.D. Candidate, Dept. of Mathematics, Rutgers University
Tuesday, December 16, 2025, 3:00-4:00 PM ET (1:00-2:00 PM MT)
In person at: Gaithersburg Bldg. 101 LR D* with VTC to Boulder 1-4072
Abstract: Press down on a sheet of paper doubled over itself and everyone knows what happens - curvature concentrates onto a collection of line segments across the sheet and the sheet lies just about flat, isometrically deformed away from the curved region. A fundamental modeling question is if equations describing elasticity can show this stress-concentration phenomenon - one which occurs in a variety of physical systems involving thin sheets. A further question is if one can determine the pattern of folds in a given compression setup from the equations of elasticity, in an appropriately reduced model only making reference to the potential line segments that might form. Such a model would encapsulate material properties, experimental setup parameters, and would hopefully be remarkably simple to recognize and visualize.
In this talk I will give some theoretical results and present some open questions involved in this project. The tools of calculus of variations and PDE theory will be gently exposited to show how one can transform energy principles for bulk elasticity into mechanics for line segments. Some ideas for applications beyond basic science research will also be discussed. Joint work with Ian Tobasco (U Mich).
Bio: Samuel Wallace is a 6th-year Mathematics PhD student at Rutgers University working with Ian Tobasco. His work has been primarily focused on mathematical material science during graduate school, in particular solid mechanics. Sam completed an NSF internship at Army COE in summer 2021 doing theoretical and numerical work on sound wave interferometry. In his free time he enjoys board games and movies with friends, and reading novels.
Host: Leroy Jia
Note: This talk will be recorded to provide access to NIST staff and associates who could not be present to the time of the seminar. The recording will be made available in the Math channel on NISTube, which is accessible only on the NIST internal network. This recording could be released to the public through a Freedom of Information Act (FOIA) request. Do not discuss or visually present any sensitive (CUI/PII/BII) material. Ensure that no inappropriate material or any minors are contained within the background of any recording. (To facilitate this, we request that cameras of attendees are muted except when asking questions.)
*Safety Precaution: The hallway leading from the Courtyard to the exit closest to B-111 and B-113 will be used by contractors to move debris, machinery, and other supplies, as well as will be heavily trafficked by the contractors throughout the process. Be aware of the safety precautions posted during this time.
Note: Visitors from outside NIST must contact Meliza Lane at least 24 hours in advance.
