Wednesday, January 28, 2026 Lunch and networking at 12:00, seminar starting at 12:30 Engineering Collaborative Research and Education (ECoRE) Building, Room 504
Sean Collier Assistant Research Professor Applied Research Laboratory at Penn State
Surprisingly little documentation exists for a bell so commonplace to the American ideology of Freedom—its sound silenced by the infamous crack well before any of us were born. While true that computational tools exist to predict such a sonance, the Liberty Bell poses a particularly challenging task due to the specific nature of “bell bronze” and lack of recorded dimensions. Hence, modal analysis may be used to estimate the natural frequencies of the bell, so to tune the numerical model for acoustic prediction. To that end, this talk discusses the modal analysis of a Liberty Bell replica located at Penn State Berhend. In particular, we explore the planning, practical conversations had, testing, and post processing of the replica. Methodologies will be emphasized, exploring expansion techniques to increase spatial fidelity and frequency-domain filtering to limit errors caused by the long ringdown. Results describe the vibration characteristics of the replica, comparison to classical results of Rossing and Perrin, and the story of how three enthusiastic acousticians worked to recreate the historic chime.