An Experimental Test Bed for Developing High-Rate Structural Health Monitoring Methods

Bryan Joyce,Jonathan Hong,Simon Laflamme,Jacob Dodson

doi:10.1155/2018/3827463

Abstract

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 configuration 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. This 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. The 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 fixed and changing configurations. A sliding mode observer with a recursive least squares parameter estimator is demonstrated that can track the system’s states and changes in its first natural frequency.

Highlights

Researchers have studied a variety of techniques and applications for structural health monitoring (SHM) [1,2,3,4]
These structures can experience high-speed impacts (>4 km/s) that result in damage propagating through the structures in microseconds [5, 6]. These 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]
This paper focuses on modeling the experimental test bed started by Abramczyk et al [17, 18] in different parameter configurations and developing a sliding mode observer (SMO) to demonstrate a model-based state estimator for tracking system changes

Summary

Introduction

Researchers have studied a variety of techniques and applications for structural health monitoring (SHM) [1,2,3,4]. 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, highspeed turbomachinery, and weapon systems. Dodson et al previously studied recursive least squares and extended Kalman filter methods for estimating model parameters in simulations of time-varying systems [14, 15] These works show promise for developing techniques for damage detection in high-rate systems, but sufficient data pertaining to these rapidly changing systems is limited. The SMO is applied to data captured either while the tip mass detaches or while the rollers move along the beam to demonstrate the ability to detect and track simulated damage to this system

Experimental Setup

Analytical and Numerical Models

Model-Based State and Parameter Estimation

Modal Testing in Fixed Configurations

Conclusions and Future Work

Disclosure