Research Article An Experimental Test Bed for Developing High-Rate Structural Health Monitoring Methods Bryan Joyce , 1 Jacob Dodson, 2 Simon Laflamme, 3 and Jonathan Hong 4 1 Energy Technologies and Materials Division, University of Dayton Research Institute, Eglin AFB, FL 32542, USA 2 Air Force Research Laboratory (AFRL/RWMF), Eglin AFB, FL 32542, USA 3 Department of Civil, Construction, and Environmental Engineering, Iowa State University, Ames, IA 50011, USA 4 Applied Research Associates, Emerald Coast Division, Niceville, FL 32578, USA Correspondence should be addressed to Bryan Joyce; bryan.joyce@udri.udayton.edu Received 28 February 2018; Revised 20 April 2018; Accepted 2 May 2018; Published 3 June 2018 Academic Editor: Daniele Baraldi Copyright © 2018 Bryan Joyce et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Complex, high-rate dynamic structures, such as hypersonic air vehicles, space structures, and weapon systems, require structural health monitoring (SHM) methods that can detect and characterize damage or a change in the system’s confguration on the order of microseconds. While high-rate SHM methods are an area of current research, there are no benchmark experiments for validating these algorithms. Tis paper outlines the design of an experimental test bed with user-selectable parameters that can change rapidly during the system’s response to external forces. Te test bed consists of a cantilever beam with electronically detachable added masses and roller constrains that move along the beam. Both controllable system changes can simulate system damage. Experimental results from the test bed are shown in both fxed and changing confgurations. A sliding mode observer with a recursive least squares parameter estimator is demonstrated that can track the system’s states and changes in its frst natural frequency. 1. Introduction Researchers have studied a variety of techniques and appli- cations for structural health monitoring (SHM) [1–4]. Much of this interest has focused on civil structures with low frequency dynamics and use SHM techniques that collect and process data on the order of several seconds or longer. Many of these classic methods are too slow to accommodate the need for real-time SHM in the growing number of advanced structures in high-rate, dynamically harsh environments, such as hypervelocity air vehicles, space structures, high- speed turbomachinery, and weapon systems. Tese structures can experience high-speed impacts (>4 km/s) that result in damage propagating through the structures in microseconds [5, 6]. Tese high-rate dynamic systems present a number of challenges to contemporary SHM and damage prognosis algorithms including the need for rapid damage detection, robustness to sensor noise, uncertainties in external forces, unknown changes in system parameters, and unmodeled dynamics [7, 8]. A number of authors have begun to study the problem of damage detection for high-rate, time-varying systems. Dodson et al. studied SHM at the microsecond timescales using strain energy and wave propagation methods [9]. Kettle, Anton, and collaborators have studied extending electromechanical impedance techniques to the megahertz frequency range for use in real-time damage detection [10–12]. Hong et al. utilized a data-driven, variable input space observer for damage detection [8, 13]. Dodson et al. previously studied recursive least squares and extended Kalman flter methods for estimating model parameters in simulations of time-varying systems [14, 15]. Tese works show promise for developing techniques for damage detec- tion in high-rate systems, but sufcient data pertaining to these rapidly changing systems is limited. Such data is needed for developing high-rate SHM techniques and gaining Hindawi Shock and Vibration Volume 2018, Article ID 3827463, 10 pages https://doi.org/10.1155/2018/3827463