Student Name: Sayantan Ghosh

Advisor: Dr. Keegan Moore

Milestone: MS Thesis Proposal

Degree Program: Aerospace Engineering

Title: A Physics-Enforced Dual-Phase Framework for Dynamics Identification in Forced Nonlinear Systems

Abstract: System identification is critical to many engineering applications, especially those involving vibrating structures. The Energy-based Dual-phase Dynamics Identification (EDDI) method is a data-driven technique that discovers equations of motion from measured responses in compliance with physical balance laws. This work expands the original EDDI method to the identification of nonlinear single-degree-of-freedom (SDOF) oscillators under external forcing. The major innovation presented here is the reformulation of EDDI to incorporate external forces into the identification process. The method is deployed in two phases to systematically extract mathematical models for the damping and stiffness of the structure. At its core, EDDI leverages conservation of energy and Newton’s second law to express the measured data in a form that allows identification of the underlying dynamics. Phase I estimates the energy dissipated by damping using conservation of energy, and then uses that estimate to identify a mathematical model for the damping. Phase II applies Newton’s second law to isolate the conservative force directly, which is then used to identify a mathematical model for the stiffness of the structure. The method is first demonstrated using a numerically simulated Duffing oscillator with known parameters to test the effectiveness of the proposed method. It is then applied to experimentally measured responses of a nonlinear oscillator with unknown stiffness and damping parameters, excited by a nonlinear external force through a magnetic stinger and a modal shaker. EDDI requires only the measured response, the external force, and the mass of the oscillator, and no prior information about the system dynamics is necessary 

Date and time: 2026-11-11, 9am-11am

Location: Weber 200 Conferce Room

Committee:
Dr. Keegan Moore (advisor), School of Aerospace Engineering
Dr. Graeme Kennedy, Associate Professor ,School of Aerospace Engineering
Dr. Alper Erturk, Professor, School of Mechanical Engineering
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