MPC Research Reports
Report Details

Title:	Local Resonances in Rail Structures
Authors:	Yuning Wu and Xuan Zhu
University:	University of Utah
Publication Date:	Oct 2024
Report #:	MPC-24-571
Project #:	MPC-672

Abstract

Zero-group velocity (ZGV) modes in rails are studied through simulation and experiments. Local resonances associated with ZGV modes appear as distinct, sharp peaks in the frequency amplitude spectrum, whose resonant frequencies can serve as indicators of the local structural integrity condition of the rail itself, assuming that one can excite, detect, and identify wave mode type with confidence. To better understand these interesting modes, semi-analytical finite element (SAFE) analysis is implemented to compute dispersion curves of a standard rail cross-sectional shape and to identify potential ZGV points and backward waves. Experimental rail dynamic data are collected from a 25-meter free rail sample with multiple excitation-sensor configurations to understand the detectability and excitability of specific resonances associated with ZGV and cutoff frequency points in rails. Spatial sampling of wave disturbance is performed to calculate the dispersion relations experimentally via two-dimensional Fourier transforms (2D-FFTs). The excellent agreement between simulation and experimental results confirms the existence of ZGV modes and cutoff frequency resonances in rails and verifies the feasibility of using impulse-based dynamic tests and piezoelectric devices for the promotion of ZGV modes.

How to Cite

Wu, Yuning, and Xuan Zhu. Local Resonances in Rail Structures, MPC-24-571. North Dakota State University - Upper Great Plains Transportation Institute, Fargo: Mountain-Plains Consortium, 2024.