Location Specific Temperature Compensation of Guided Wave Signals in Structural Health Monitoring
Location Specific Temperature Compensation of Guided Wave Signals in Structural Health Monitoring
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DOI：
10.1109/tuffc.2019.2940451
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发表时间：
2020-01-01
影响因子：
3.6
通讯作者：
Cawley, Peter
中科院分区：
文献类型：
--
作者：
Mariani, Stefano;Heinlein, Sebastian;Cawley, Peter
在导波结构健康监测中，通常通过识别通过基线减法获得的高残差来检测缺陷，其中从“当前”信号中减去较早的测量。不幸的是，变化的环境和操作条件（EOC），如温度，也会产生信号变化，因此，潜在的高残差。虽然已经开发的大多数温度补偿方法的目标是由变化的温度引起的改变的波速，但是没有解决许多其他影响，例如衰减的变化、由换能器激发的不同模式的相对振幅以及换能器频率响应。温度补偿程序的开发，其目标是纠正任何空间相关的信号变化，这是一个系统的温度函数。在每个结构位置处，计算对信号随温度变化进行建模的校准函数，并将其用于校正测量结果，使得在不存在缺陷的情况下，残差减小到接近零。这种新的方法被应用到一组导波信号收集在一个导波管道监测系统的盲试使用T（0，1）模式，产生的残差从温度解耦，并减少了至少50相比，使用标准的方法获得的位置远离结构特征，并通过超过90的功能，如管道端部。因此，该方法有望大大提高小缺陷的可检测性，特别是在现有的管道特征。
In guided wave structural health monitoring, defects are typically detected by identifying high residuals obtained through the baseline subtraction method, where an earlier measurement is subtracted from the "current" signal. Unfortunately, varying environmental and operational conditions (EOCs), such as temperature, also produce signal changes and hence, potentially, high residuals. While the majority of the temperature compensation methods that have been developed target the changed wave speed induced by varying temperature, a number of other effects are not addressed, such as the changes in attenuation, the relative amplitudes of different modes excited by the transducer, and the transducer frequency response. A temperature compensation procedure is developed, whose goal is to correct any spatially dependent signal change that is a systematic function of temperature. At each structural position, a calibration function that models the signal variation with temperature is computed and is used to correct the measurements, so that in the absence of a defect the residual is reduced to close to zero. This new method was applied to a set of guided wave signals collected in a blind trial of a guided wave pipe monitoring system using the T(0, 1) mode, yielding residuals de-coupled from temperature and reduced by at least 50 as compared with those obtained using the standard approach at positions away from structural features, and by more than 90 at features such as the pipe end. The method, therefore, promises a substantial improvement in the detectability of small defects, particularly at the existing pipe features.