A temperature compensation approach using dynamic time warping for electro-mechanical admittance-based concrete structural damage identification

Ambient temperature effect on electro-mechanical admittance (EMA) signals always imposes a threat to the accurate identification of concrete damages when using surface-mounted piezoelectric lead zirconate titanate transducers. To reduce adverse temperature effect on the EMA signals, this paper proposed a dynamic-time-warping-based temperature compensation approach for concrete structural damage identification, making use of the similarity between two series via accumulating Euclidean distance under admissible temporal alignments. Validating experiments were conducted on a lab-scaled concrete cube with artificial cracks, and practical application on a full-scaled assembled tunnel structure undergone bolt-loosened defects. The approach was sufficiently verified through comparing with the traditional effective frequency shift method for restoration of the conductance signatures altered by temperature. Experimental results demonstrated that the approach possessed superior performance both for pure temperature compensation and temperature-compensated damage identification to the traditional one, which is promising for practical extension to the in situ concrete infrastructural health monitoring.