Efficient Acquisition of Baseline Signals in Ultrasonic Guided Wave Structural Health Monitoring (SHM)

摘要

Temperature compensation methods - Optimal Baseline Selection (OBS) and Optimal Stretch Method (OSM) - have been succesfully used to suppress temperature effects in ultrasonic guided wave signals. However, the methods require a set of baseline signals recorded on an undamaged structure at a range of temperatures before SHM can be realised. This is difficult to achieve on structures exposed to real environmental conditions when there is limited control or knowledge of temperature variations. Therefore, a novel algorithm has been designed that continuously builds a set of baseline signals well separated in the temperature domain without having any information on the structure operating conditions. The performance when differentiating between damage and temperature effects in the signals based on sensor array images and baseline set growth parameters have been tested with data from SHM experiments. This makes the acquisition of baseline signals an evolutionary process which can be incorporated into SHM.