Investigation of cross-sensitivities of the potential drop method for structural health monitoring of civil structures

Abstract Currently, structural health monitoring (SHM) systems are not in widespread use for monitoring civil structures because of low defect sensitivity and high cross-sensitivities of most SHM techniques available. The potential drop method (PDM), commonly used in material testing, is a possible method for SHM of large metallic civil structures combining high defect sensitivity and high area monitoring capability. The current state of the art lacks experimental evidence of the applicability to large specimens under the demanding operating conditions of SHM. Here, we investigated the PDM as an SHM system experimentally by analyzing the cross-sensitivity to temperature changes and performed a temperature compensation. We present an optimized method for suppressing the unwanted influence of mechanical loads and increasing the defect sensitivity. The temperature influence was separated from the defect-induced impedance change and effectively suppressed by compensation. Thus, cross-sensitivity does not limit PDM in SHM for large metallic civil structures with temperature compensation. PDM is a promising technique for SHM which could facilitate the widespread use of SHM of conductive civil structures.