Effects of Applied Load on Guided Waves Based Structural Health Monitoring of CFRP Composites
Carbon fiber reinforced polymer (CFRP) materials are desirable for many high performance applications, but pose challenges due to their complicated damage mechanics. Implementing a structural health monitoring (SHM) strategy for CFRP composite structures is one approach to assess the structure in real-time. Application of SHM requires not only the ability to localize, classify, and quantify damage in a structure, but also to compensate for changing environmental, operational, and state conditions. This work will focus on one such problem, specifically compensating for effects of applied load on guided waves based SHM systems mounted on composite coupons. Ultrasonic signals are propagated through the material using piezoelectric elements, and by analyzing signal changes from the SHM system when experiencing effects from applied load the goal is to predict loading on a structure using data from the on-board SHM system. Signal features extracted from the ultrasonic sensor signals, including amplitude, time of flight, power spectral density, and energy, are used to distinguish effects from applied load. Using combinations of these signal features and the theoretical effects on the guided wave signal due to applied load from acoustoelastic theory, statistical models are formed which estimate the tensile load applied to CFRP test coupons.
Author: Colleen L. Rosania, Natasha C. Bradley, Mulugeta A. Haile, and Fu-Kuo Chang
Conference: SAMPE Seattle 2017